SSL3250A Photo flash dual LED driver
Contents
1. 0 1 3 5 7 Indicator current using 12C mode Fig 10 Indicator LED currents in I2C mode gt Register value 014aaa368 22 5 20 0 17 5 lj IND mA 12 5 10 0 7 5 No o 5o 165 50 25 Indicator current using direct control mode Fig 11 Indicator LED currents in Direct enable mode gt Register value kQ 014aaa369 8 4 Protection circuits There are several protection circuits integrated in the device These protection circuits protect the device and the application against defects The SSL3250A has four protection circuits that will inhibit switching of the converter programming the status register 03h and pulling LOW the interrupt line The interrupt line which can be connected to external logic signaling an error condition The external logic can read the status register to determine which fault caused the interrupt and decide on the proper action to take When not using the 12C mode the status register cannot be read out but the interrupt line still is functional to signal a fault condition NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 12 of 26 NXP Semiconductors SS L3250A 8 4 1 8 4 2 8 4 3 SSL3250A 5 Photo flash dual LED driver The four protection circuits and their bits in the status register are as follows e Overvoltage protectio2. ars T SSL3250A Photo flash dual LED driver Rev 05 16 December 2009 Product data sheet 1 General description 2 Features The SSL3250A is a photo flash LED driver designed for battery operated mobile devices such as mobile phones and PDAs The boost converter delivers high performance and drives a single or dual high brightness LED at up to 500 mA with over 85 efficiency The driver can be programmed to operate in Flash Torch or Indicator Video on mode The small silicon size and the high internal switching frequency of 1 2 MHz minimize the SSL3250A footprint making it very suitable for mobile phones where space is limited and only requiring four external components Driving a high power flash LED within its safe operating limits was a concern when the SSL3250A was designed so a time out function can be programmed via the I C interface which will prevent overstressing the LED Due to the specific requirements of a mobile phone the flash current can be rapidly lowered during RF transmit by using optional external setting resistors High power single or dual LED output driving up to 500 mA flash current Separate indicator LED output of 2 5 mA to 20 mA Output voltage of up to 9 5 V Wide input voltage range of 2 7 V to 5 5 V High efficiency over 85 at optimum output current Switching frequency of 1 2 MHz Flash Torch and Indicator mode supported Internally timed fla
3. C Tamb ambient temperature 40 485 C Tstg storage temperature 40 150 C Vesp electrostatic discharge class 2 voltage human body model 2 2000 V all pins machine model al 150 V all pins charged device BI 500 V model all pins 1 Tolerant to the specified maximum voltage while operating Do not apply voltages externally this may cause permanent damage to the device 2 Equivalent to discharging a 200 pF capacitor through a 0 75 uH coil and a 10 Q resistor 3 Equivalent to discharging the device charged with gt 10 MO resistor through a 1 Q measurement resistor NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 19 of 26 NXP Semiconductors SS L3250A Photo flash dual LED driver 11 Thermal characteristics Table8 Thermal characteristics Symbol Parameter Conditions Typ Unit Rth a thermal resistance from junction to ambient based on modeling on a four layer 63 K W board in free air and five thermal vias under the ICU 1 The junction to ambient thermal resistance is dependent on the board layout PCB material application and environmental conditions 12 Characteristics Table 9 Characteristics Vj 3 0V to 5 5 V Tamb 40 C to 85 C unless otherwise specified Symbol Parameter Conditions Min Typ Max Unit General voltage levels VI input voltage on pin VIN 3 0 5 5 V ViexingviN extended input voltage on pin VIN
4. 0009099999099 ooo pin 1 indicator direction of unreeling 002aae613 Fig 1 SSL3250AHN C1 528 with package rotated 90 clockwise with pin 1 in quadrant 2 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 2 of 26 NXP Semiconductors SSL3250A 6 Block diagram Photo flash dual LED driver VBaT t INTERNAL SUPPLY 12C INTERFACE AND CONTROL Fig 2 Block diagram 4 7 uF PGND LINEAR CURRENT SINK CURRENT FEEDBACK UP CONVERTER LN 3 2 2 uH 1 Ceramic SSL3250A 4 7 uF I Ceramic PGND One or two LEDs 014aaa286 SSL3250A 5 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 3 of 26 NXP Semiconductors SSL3250A 7 Pinning information Photo flash dual LED driver 7 1 Pinning m terminal 1 s E z index area to Q E 3 a a z o a z a IND 014aaa363 Transparent top view Fig 3 Pin configuration terminal 1 index area is die pad GND 7 2 Pin description Table3 Pin description Symbol Pin Type Description R TR analog IO setting resistor for torch current R FL analog lO setting resistor for flash current SCL EN2 Serial Clock Line SCL in I2C mode Enable 2 in Direct enable mode SDA EN1 4 O Serial Data Line SDL in I2C mode Enable 1 in D
5. 2l 2 75 5 5 V Vi UVLO undervoltage lockout input voltage V falling 2 55 2 65 2 8 V Vhys UvLo undervoltage lockout hysteresis Vi rising 50 100 150 mV voltage General current levels Isa shutdown current Shut down mode ACT 0 1 uA lieak LX leakage current on pin LX ACT 20 0 5 uA limriiM ux peak current limiter current on inductor peak current limiter 2 2 2 4 A pin LX Output voltages on external resistor pins VR IND voltage on pin R IND independent of load B 1 17 1 22 1 27 V Vn TR voltage on pin R TR independent of load Bl 1 17 1 22 1 227 V Vn FL voltage on pin R FL independent of load B 1 17 1 22 1 27 V Allowed input voltages on external resistor pins Vn IND voltage on pin R IND B 1 4 Vi V Vn TR voltage on pin R TR BI 4 4 z Vi V Vn FL voltage on pin R FL B 1 4 Vi V External resistors Rex R ip external resistance on pin R IND IF SEL 1 resistors used DE 25 165 kQ Rext R_TR external resistance on pin R_TR IF_SEL 1 resistors used is 25 200 kQ Rext R_FL external resistance on pin R_FL IF SEL 1 or 0 resistors used E 50 357 kQ SSL3250A_5 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 20 of 26 NXP Semiconductors SSL3250A Table 9 Characteristics continued Vj 3 0V to 5 5 V Tamb 40 C to 85 C unless otherwise specified Photo flash dual LED driver Symbol Parameter Conditions High power LED parameters Vo outpu
6. Rectifier diode 22000055 18 PCB layout 2 2 2 0 cece eee 18 Limiting values eee eee eee 19 Thermal characteristics 20 Characteristics lsllslsus 20 founded by 13 14 15 16 16 1 16 2 16 3 16 4 17 18 Package outline 00 e eee e eee 23 Abbreviations lr 24 Revision history sese 24 Legal information 25 Data sheet statuS 25 Definitions x yu RIPE Re rFRWe 25 Disclaimers 0 000 cece eee 25 Trademarks size dee ede ee ee 25 Contact information 25 Contenis cu s RR A EMEN EE 26 Please be aware that important notices concerning this document and the product s described herein have been included in section Legal information NXP B V 2009 All rights reserved For more information please visit http www nxp com For sales office addresses please send an email to salesaddresses nxp com Date of release 16 December 2009 Document identifier SSL3250A 5
7. as the first byte after the start condition in the I C bus protocol Figure 14 MSB LSB pep pe paro oe s n 014aaa288 Fig 14 1 C slave address There is one address byte required since 7 bit addresses are used The last bit of the address byte is the read write bit and should always be set according to the required operation This 7 bit IC address is 0110000b 30h The 7 bit address plus the R W bit create an 8 bit write address of 60h and a read address of 61h The second byte sent to the SSL3250A is the subaddress of a specific register Data After the subduers have been sent the data byte s are sent The definition of the data byte s is given in Figure 12 After each data byte an acknowledge is given and the subduers is automatically incremented to the next subduers A description of the data that can be programmed in the registers is given in the register map in Section 8 7 3 Register map Table 6 Description of registers Legend default register value Address Register Bit Symbol Access Value Description 00h Current control 7to3 MAIN LEVEL R W 00000 OFF default 00001 Torch mode see Section 8 3 3 SSL3250A 5 00010 Torch mode see Section 8 3 3 01010 Torch mode see Section 8 3 3 01011 Torch mode see Section 8 3 3 01100 Flash mode armed see Section 8 3 4 01101 Flash mode armed see Section 8 3 4 11110 Flash mode armed see Section 8 3 4 11111 Flash mode armed see Section 8 3
8. standard refer to the document UM10204 I C bus specification and user manual version 0 3 June 2007 which can be downloaded from the NXP web site www nxp com The following describes the protocols used by the SSL3250A for the read and write sequences The read sequence may use a repeated start condition during the sequence to avoid that the bus is released during the communication The sequences can be used to read or write only one data byte or to read or write a sequence of data bytes Figure 12 shows a write sequence for a single byte write Figure 13 show the read sequence for a single byte E Slave address Sub address n eee s From master to slave S START condition P STOP condition A Acknowledge N Not Acknowledged From slave to master 014aaa292 Fig 12 Single byte I C write sequence E Slave address Sub address n sp eee 7 ISI S START condition From master to slave P STOP condition A Acknowledge N Not Acknowledged From slave to master Sr Start repeat 014aaa290 Fig 13 Single byte I C read sequence NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 15 of 26 NXP Semiconductors SS L3250A 8 7 1 8 7 2 8 7 3 Photo flash dual LED driver Addressing Each SSL3250A in an I C bus system is activated by sending a valid address to the device The address always has to be sent
9. 009 18 of 26 NXP Semiconductors SS L3250A Photo flash dual LED driver If the SSL3250A is used in Direct enable mode and external resistors are used place the external resistors near the SSL3250A to minimize disturbance on the output current Connect the other end of the resistors to a clean ground that is ground that is not carrying any large currents It is preferable to connect all resistor grounds to one trace and connect that trace to the GND pin of the SSL3250A The preferred minimum trace width for the high current width is 15 mil per Ampere 10 Limiting values SSL3250A 5 Table 7 Limiting values In accordance with the Absolute Maximum Rating System IEC 60134 Voltages referenced to GND Symbol Parameter Conditions Min Max Unit Vi input voltage 0 5 45 5 V VACT voltage on pin ACT 0 5 Vi V Vspa voltage on pin SDA 0 5 Vi V Vent voltage on pin EN1 0 5 Vi V Vsci voltage on pin SCL 0 5 Vi V VEN2 voltage on pin EN2 0 5 Vi V VstrB voltage on pin STRB 0 5 Vi V Vir_seL Voltage on pin IF SEL 0 5 Vi V Vint voltage on pin INT 0 5 Vi V Vi IND voltage on pin IND 0 5 Vi V ViED voltage on pin LED 0 5 voli V Vo output voltage 0 5 4208 V Vix voltage on pin LX 0 5 201 V VR IND voltage on pin R IND 0 5 Vi V Vn TR voltage on pin R TR 0 5 Vi V Vn FL voltage on pin R FL 0 5 Vi V VPGND voltage on pin PGND 0 5 40 5 V Prot total power dissipation Tamb 85 C 1 0 Ww Tj junction temperature 40 150
10. 1 of 26 NXP Semiconductors SS L3250A Photo flash dual LED driver Table 9 Characteristics continued Vj 3 0V to 5 5 V Tamb 40 C to 85 C unless otherwise specified Symbol Parameter Conditions Min Typ Max Unit 12C interface Vit LOW level input voltage 0 5 V Vin HIGH level input voltage 1 2 VIN V VoL LOW level output voltage Isink 3 mA 0 0 4 V scL SCL clock frequency 0 400 kHz Digital levels EN1 EN2 STRB ACT Vit LOW level input voltage digital 0 s 0 5 V Vin HIGH level input voltage digital 1 2 V Digital levels IF SEL pin Vit LOW level input voltage IF_SEL pin 0 0 5V V Vin HIGH level input voltage IF_SEL pin 0 5Vi Vi V Digital levels INT VoL LOW level output voltage Isink 3 mA 0 0 4 V li HIGH level input current 0 0 5 uA Temperature Tamb ambient temperature 40 25 85 C Totp overtemperature protection trip temperature rising 150 C Totp hys overtemperature protection trip temperature falling 20 C hysteresis 1 All typical values are measured at Tamb 25 C and V 3 6 V 2 When operating in an extended input voltage range the device will be fully functional but has a reduced performance specification on certain parameters An extended input voltage range is entered when the input voltage is dropping below 3 0 V assuming the device is not in undervoltage lockout mode 3 When no external resistor is connected the device will apply a de
11. 4 21 100 IND LEVEL R W 000 OFF default 001 indicator ON 2 5 mA 011 indicator ON 5 mA 111 indicator ON 17 5 mA NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 16 of 26 NXP Semiconductors SS L3250A Photo flash dual LED driver Table 6 Description of registers continued Legend default register value Address Register Oth Timer control 02h Flash strobe 03h Status Bit Symbol Access Value Description 7to5 Reserved s 4 TO DEF R W 0 select time out limit default 1 select timed operation 3to0 TO R W 0000 820 ms default 0001 765 ms 1110 56 ms 1111 1ms 7to1 Reserved E 0 FLASH STRB R W 0 1 enable flash 7t04 Reserved 3 OStrig R 0 LED not shorted to GND 1 LED shorted to GND 2 OTPtrig R 0 temperature lt maximum temperature 1 temperature gt maximum temperature protection triggered 1 TOtrig R 0 flash time time out 1 flash time gt time out protection triggered 0 OVPtrig R 0 Vo lt Vovp 1 Vo gt Vovp protection triggered 9 Application design in information SSL3250A_5 9 1 9 2 Input capacitor For good input voltage decoupling a low ESR ceramic capacitor is highly recommended A 4 7 uF X5R X7R 6 3 V is the minimum recommended value Since the input capacitor is supplying the input ripple current a larger capacitor will improve transient behavior of the regulator and EMI behavior of the power supply Tak
12. ASH STRB bit in Flash Strobe register 02h The duration of the flash can be determined by a timer STRB triggering or by a time out The flash timing is given by Equation 3 and in Section 8 4 2 Iigp T x 35 mA 15 mA x Register 3 R _FL When using the Direct enable mode the flash current can be defined by an external resistor connected to the R_FL pin The current in the main LED is defined using Equation 4 When not using the current set resistor the flash current will be set to a default level of 500 mA The default current is equal to connecting an external current set resistor of 50 KQ Entering Flash mode in Direct enable mode can be done using the EN1 and EN2 pins The LED will stay on in Flash mode for as long as the enable pins are set to Flash mode but is limited to 820 ms maximum by the time out timer 50 kQ Ijgp Sa x 500 mA 4 RR FL When no external current set resistor is used the R_FL pin can be left unconnected but is preferably connected to VIN Never connect the R_FL pin to GND as this will cause unnecessary reference currents to flow to GND Figure 7 illustrates the Flash mode current setting equation for I C while Figure 8 illustrates the Flash mode current setting equation for the Direct enable mode A 600 ILED mA No 500 Resistor 375 66 7 250 100 215 125 200 110 LL L r pe 55 o n ooa 0 12 16 20 24 28 32 Register Flash
13. EL Interface mode Relevant controls 0 12C mode SDA SCL STRB ACT R FL INT 1 Direct enable mode EN1 EN2 ACT INT R TR R FL R IND INT NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 5 of 26 NXP Semiconductors SS L3250A 8 2 1 Photo flash dual LED driver Using the direct enable control When the Direct enable mode is used the device can be switched to the various operational modes using the ACT EN1 and EN2 control signals The definition of these control signals is given in Table 5 The current in the main LED in Torch mode and Flash mode and the LED current in the indicator LED can be independently controlled by the external current setting resistors R IND R TR and R FL When no external current setting resistors are used the pins should preferably be connected to VIN and the default current levels for each LED Table 5 Enable definition ACT EN2 EN1 Operational mode LED active 0 X X Shut down mode 1 0 0 Standby mode 1 0 1 Indicator mode indicator LED 1 1 0 Torch mode main LED 1 1 1 Flash mode main LED The relation between the ACT and EN1 EN2 signals is given in Figure 4 All modes can be entered from the Standby mode Entering Torch mode or Indicator mode before entering Flash mode is not required Main LED current LED current Shut down o M tstart soft Indicator wa a e S EN2 ee O e a S ACT Fig 4 Functi
14. current level In 12C mode the indicator LED current can be set between 2 5 mA and 17 5 mA The internal 3 bit register sets the actual indicator LED according to the formula in Equation 6 The external resistor R IND is ignored I np Register x 2 5 mA 6 When using the Direct enable mode the indicator current can be determined by an external resistor R_IND The indicator current is defined using Equation 7 It can be set between 2 5 mA and 20 mA When not using the resistor the indicator current will be set to a default level of 10 mA This current is similar to connecting an external resistor of 50 kQ Entering Flash mode in Direct enable mode can be done using the EN1 and EN2 pins The LED will stay on in Flash mode for as long as the enable pins are set 50 kQ Rr IND Ij IND x 10 mA 7 If there is no resistor connected to the R IND pin it can either be left unconnected or connected to VIN Never connect the R IND pin to GND since it will cause unnecessary reference currents to flow to GND Figure 10 illustrates the Indicator mode current setting equation for 12C while Figure 11 illustrates the Indicator mode current setting equation for the Direct enable mode NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 11 of 26 NXP Semiconductors SSL3250A SSL3250A 5 Photo flash dual LED driver lj iND mA 17 5 12 5 7 5 2 5 A
15. current using I2C mode Value kQ 014aaa366 Fig 7 Flash mode LED current in IC mode NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 9 of 26 NXP Semiconductors SS L3250A 8 3 5 8 3 6 SSL3250A 5 Photo flash dual LED driver 600 ILED mA 500 400 300 200 100 70 0 gt 357 125 50 Resistor Flash current using direct control mode Value kQ 014aaa367 Fig 8 Flash mode LED current in Direct enable mode Timed Flash mode The timed operation of the Flash mode can only be used in the I C interface mode When the flash is used in Timed mode bit 4 TO_DEF 1 in Timer control register 01h the internal timer will switch off the main LED after the preprogrammed maximum time in the timer control register has expired The timer starts when the Flash mode is activated either by the software strobe FLASH_STRB bit in register 02h or by a LOW to HIGH transition of the hardware strobe STRB pin signal In timed mode strobing of the flash is edge sensitive therefore the flash time is independent of the level of the software or hardware strobe signal The flash time is set according to Equation 5 llash 620 ms Register x 54 6 ms 5 Once the Flash time has expired no interrupt will be generated nor will it be flagged in the status register A new flash period can be started immediately after the p
16. ersedes SSL3250A_4 SSL3250A 3 SSL3250A 2 SSL3250A 1 SSL3250A 5 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 24 of 26 NXP Semiconductors SSL3250A 16 Legal information Photo flash dual LED driver 16 1 Data sheet status Document status 1 Product statusi3 Definition Objective short data sheet Development Preliminary short data sheet Qualification Product short data sheet Production This document contains data from the objective specification for product development This document contains data from the preliminary specification This document contains the product specification 1 Please consult the most recently issued document before initiating or completing a design 2 The term short data sheet is explained in section Definitions 3 The product status of device s described in this document may have changed since this document was published and may differ in case of multiple devices The latest product status information is available on the Internet at URL http www nxp com 16 2 Definitions Draft The document is a draft version only The content is still under internal review and subject to formal approval which may result in modifications or additions NXP Semiconductors does not give any representations or warranties as to the accuracy or completeness of information included herein and shall have no liability
17. es there are two power states One state is when the internal NMOS switch is on and one when the NMOS switch is off During each state there will be a current loop made by the power components that are conducting Arrange the input capacitor rectifier diode and output capacitor in such a way around the SSL3250A that during each of the two states the current loop is conducting in the same direction This prevents phase reversal of the magnetic field and reduces radiated EMI The current loop area should be kept small by placing the power components as close as possible to the SSL3250A Use ground planes to keep loop areas to a minimum Priority should be given to positioning the output capacitor and the rectifier diode as close as possible to the LX and PGND nodes of the SSL3250A Since large currents will flow from the input capacitor to the inductor and not into the VIN pin of the SSL3250A it is wise to locate the input capacitor near the inductor The VIN pin should be star connected to the positive pad of the input capacitor It is recommended to place an extra 100 nF capacitor from VIN to GND directly next to the SSL3250A PGND and GND of the SSL3250A should be directly connected to each other preferably by using the die pad area under the SSL3250A Place the ground connection of the output capacitor as close as possible to the PGND pin of the SSL3250A NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2
18. fault current setting See Section 8 3 for details Corresponding pins should then be connected to high 1 4 V 4 Higher resistor values than the maximum are considered as no resistor is connected and therefore result in the default current setting 5 Lower resistor values than the minimum will result in large currents being drawn from the device resulting in bad operation 6 To accommodate two LEDs with a spread in Vr between 2 7 V and 4 3 V each 7 Only valid in Boost mode typically in a dual LED configuration When in linear mode used in specific cases of single LED applications excess voltage will fall over the LED pin SSL3250A 5 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 22 of 26 NXP Semiconductors SS L3250A Photo flash dual LED driver 13 Package outline HVQFN16 plastic thermal enhanced very thin quad flat package no leads 16 terminals body 3 x 3 x 0 85 mm SOT758 3 terminal 1 index area Ei E A i Y c t A1 Y detail X 4 4 __ gt 6 j 12e j Boh v P CJA B wc LU 5 8 9 e E Eh e2 12e 12 term
19. for the consequences of use of such information Short data sheet A short data sheet is an extract from a full data sheet with the same product type number s and title A short data sheet is intended for quick reference only and should not be relied upon to contain detailed and full information For detailed and full information see the relevant full data sheet which is available on request via the local NXP Semiconductors sales office In case of any inconsistency or conflict with the short data sheet the full data sheet shall prevail 16 3 Disclaimers General Information in this document is believed to be accurate and reliable However NXP Semiconductors does not give any representations or warranties expressed or implied as to the accuracy or completeness of such information and shall have no liability for the consequences of use of such information Right to make changes NXP Semiconductors reserves the right to make changes to information published in this document including without limitation specifications and product descriptions at any time and without notice This document supersedes and replaces all information supplied prior to the publication hereof Suitability for use NXP Semiconductors products are not designed authorized or warranted to be suitable for use in medical military aircraft space or life support equipment nor in applications where failure or malfunction of an NXP Semiconductors product ca
20. h A time out timer limits the maximum ON time of the flash In both control modes the flash time out time is set to a fixed level of 820 ms When the flash strobe signal is set to LOW in I2C control mode bit 0 in register 02h is set to 0 When the EN1 signal is set to LOW before the time out timer has expired in Direct enable mode the time out timer is reset When a time out situation is encountered the TOtrig flag bit 1 is set in the status register See also Section 8 3 5 Overtemperature protection If the chip temperature exceeds its limit Toy see Table 9 switching of the converter is inhibited until the temperature drops below its limit minus a small hysteresis When an overtemperature situation is encountered the OTtrig flag bit 2 is set in the status register NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 13 of 26 NXP Semiconductors SS L3250A Photo flash dual LED driver 8 4 4 Short circuit protection 8 8 SSL3250A 5 4 5 4 6 8 5 8 6 8 7 To prevent device and battery overloading the converter is short circuit protected In case the LED pin is shorted to GND due to an application failure the switching of the converter is inhibited Typical response times between detection of the LED pin shorted to GND and inhibit switching of the converter is less than 1 ms The short circuit protection is functional at any time during Torch mode and al
21. inal 1 index area Dp 0 2 5 5 mm 1 1 scale DIMENSIONS mm are the original dimensions UNIT ae Ai A4 b c D Dy Dn E E4 En e e1 e2 L v w y y1 0 05 0 7 0 30 3 1 2 85 1 6 3 1 2 85 1 6 0 5 mm 99 ooo oe baa 29 265 14 29 265 14 05 15 15 os 1 005 0 05 0 1 OUTLINE REFERENCES EUROPEAN VERSION IEC JEDEC JEITA PROJECTION ISSUE DATE SOT758 3 MO 220 E 08 02 08 Fig 15 Package outline SOT758 3 HVQFN16 SSL3250A_5 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 23 of 26 NXP Semiconductors SSL3250A 14 Abbreviations Photo flash dual LED driver Table 10 Abbreviations Abbreviation EMI ESR IC IO LED MOSFET NMOS PDA PWM RF Description ElectroMagnetic Interference Equivalent Series Resistance Integrated Circuit Input Output Light Emitting Diode Metal Oxide Semiconductor Field Effect Transistor N type Metal Oxide Semiconductor Personal Digital Assistants Pulse Width Modulation Radio Frequency 15 Revision history Table 11 Revision history Document ID SSL3250A_5 Modifications SSL3250A 4 SSL3250A 3 SSL3250A 2 SSL3250A 1 Release date 20091216 Data sheet status Change notice Product data sheet Equation 1 modified 20091104 20090630 20090421 20090205 Product data sheet Product data sheet 7 Product data sheet Product data sheet Sup
22. ing options sssaaa nanan 2 Marking i iussisse ia eee nh 2 Block diagram Rete se 3 Pinning information Ll 4 PINNING aus using iba ad Ea es 4 Pin description 2200 0005 4 Functional description 5 Introduction 20000e cee ee eee 5 Interface modes 200005 5 Using the direct enable control 6 Using the 12C control 000 6 Operational modes lilius 7 Shut down mode luusuuus 7 Standby mode 20 000 ulus 7 Torch mode 200 cee eee eee 7 Flash mode sese cR Rena 9 Timed Flash mode 2 2 55 10 Flash mode during RF transmit 10 Indicator LED 200 0055 11 Protection circuits 05 12 Overvoltage protection 13 Untimed Flash mode 13 Overtemperature protection 13 Short circuit protection 14 Interrupt line llle 14 Undervoltage lockout 14 SOIL Bo g sr eS ee eee 14 Peak currentlimit 5 14 I C bus protocol 0 0 00 ee 14 Addressing 20 e eee eee ee eee 16 Dalat C keg ee E eee wie 16 Register map 00e cece eee 16 Application design in information 17 Input capacitor 000 0 0 17 Output capacitor 0005 17 Ind ctor omes ERRARE eden 18
23. ing the capacitor DC bias and the temperature derating specifications into account a 10 uF X5R X7R is preferred Although it is increasing the component count a smaller capacitor of 100 nF X5R X7R placed in parallel to the input capacitor will also improve EMI behavior When the circuit is used in other than battery powered applications and the input capacitor is located relatively far from the DC buffer capacitors it is recommended to add a 150 uF tantalum or a 470 uF electrolytic capacitor in parallel near the input capacitor Output capacitor The output capacitor supplies the current to the main LED while the inductor is being charged and it also ensures loop stability The minimum capacitance for stable loop operation would be 2 2 uF but taking the capacitor DC bias and the temperature derating specifications into account a low ESR ceramic capacitor of 4 7 uF X5R X7R is highly recommended A higher value of capacitance will improve output current ripple while NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 17 of 26 NXP Semiconductors SS L3250A SSL3250A 5 9 3 9 4 9 5 Photo flash dual LED driver maintaining loop stability The SSL3250A overvoltage limit on Vo is 10 3 V typ The rated voltage of the output capacitor should be at least 16 V For solution size reasons lower value ceramic capacitors could be placed in parallel Inductor The device has been desig
24. irect enable mode R_IND 5 analog lO setting resistor for indicator current IND 6 analog indicator LED current sink VO 7 analog O output voltage GND 8 ground ground LED 9 analog feedback of the main LED current IF_SEL 10 interface select choose between direct enable control or 12C INT 11 O interrupt output open collector PGND 12 ground power ground LX 13 analog inductor connection VIN 14 input input voltage ACT 15 l activate STRB 16 l strobe signal to enable flash in 12C mode die pad analog exposed die pad connect to GND SSL3250A 5 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 4 of 26 NXP Semiconductors SS L3250A Photo flash dual LED driver 8 Functional description SSL3250A 5 8 1 8 2 Introduction The SSL3250A is an asynchronous boost converter intended to drive either a single high power flash LED or two high power flash LEDs in series The main LED current is controlled by the output voltage of the boost converter and the integrated linear current sink The SSL3250A has two interface modes and five operational modes The control interface is selected by the interface select pin IF SEL Depending on the interface mode selected the device can either be controlled by an I C interface or by external enable lines Both interface modes control the five operational modes These operational modes are Shut down mode Standby mode Indicator mode T
25. l modes Shut down mode The device is in Shut down mode when the activate pin ACT is LOW In Shut down mode the internal circuitry of the device is turned off to guarantee a low shut down current The N channel MOSFET NMOS is set to high impedance To limit the LED current to a minimum leakage the current sink circuitry for both the main LED and the indicator LED are switched to high impedance After making the pin ACT HIGH the device will start up and is ready to receive commands through the selected interface Standby mode In Standby mode the internal circuitry of the device remains on but the converter is not switching The NMOS is set to high impedance To limit the LED current to a minimum leakage the current sink circuitry for both the main LED and the indicator LED are switched to high impedance In this mode the device is able to respond to I2C communication Torch mode The Torch mode allows the main LED to be switched on without timing limitations at a lower LED current setting The Torch mode current in the main LED can be set between 50 mA and 200 mA in both the 12C and Direct enable control mode In IC mode the LED current is defined by entering a value between a minimum of 1 and a maximum of 11 in the current control register In 12C mode the external R TR resistor is ignored If an external R FL resistor is connected this resistor will also scale down the set torch current See Section 8 3 6 The current in the mai
26. n Time out protection Overtemperature protection Output short protection When a protection is triggered switching of the IC is inhibited without a soft ramp down of the current in the main LED and also the indicator LED will be switched off To recover from this fault condition in 12C mode write 00h to the current control register 00h to clear the status register release the INT line After clearing the status register the current control register can be reloaded and the flash can be retriggered Reloading the other registers is not necessary as they will not lose their value when an interrupt is generated In Direct enable mode the status register is cleared and the INT line is released by making both the EN1 and EN2 pins IO Overvoltage protection If the output voltage Vo exceeds its limit Vovp see Table 9 switching of the converter is inhibited The output voltage will exceed Voy limit when no LEDs are connected between pins VO and LED In some cases an overvoltage protection may occur when the LED pin is shorted to GND during the period a Flash is generated The converter is trying to compensate for the loss of feedback current by increasing Vo When an overvoltage is encountered the OVPtrig flag bit 0 is set in the status register Untimed Flash mode To avoid overloading of the main LED during a flash in Direct enable mode or I C control mode in untimed Flash mode bit 4 TO DEF 0 in Timer control register 01
27. n LED using I2C mode is defined using Equation 1 When not using the resistor R FL assume a value of 50 kQ in the equation Entering Torch mode is done by writing the required current setting in the current control register The LED will light to the set torch current Switching off the Torch mode can be done by writing Oh into the current control register or by entering Flash mode see Section 8 3 4 fe SG LED Rp x 35 mA 15 mA x Register 1 _FL When using the Direct enable mode the torch current is defined by an external resistor connected to the R_TR pin The LED current is defined using Equation 2 When not using the current set resistor the torch current will be set to a default level of 125 mA The NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 7 of 26 NXP Semiconductors SS L3250A SSL3250A 5 Photo flash dual LED driver default current is equal to connecting an external current set resistor of 50 kO Entering Torch mode in Direct enable mode can be done using the EN1 and EN2 pins The LED will stay on in Torch mode for as long as the enable pins are set to Torch mode 50 kQ liED R x 125 mA 2 TR When not using an external resistor the R TR pin can be left unconnected but it is preferably connected to VIN Never connect the R_TR pin to GND since it will cause unnecessary reference currents to flow to GND Figure 5 illustrates the Torch mode current
28. n reasonably be expected to result in personal injury death or severe property or environmental 17 Contact information damage NXP Semiconductors accepts no liability for inclusion and or use of NXP Semiconductors products in such equipment or applications and therefore such inclusion and or use is at the customer s own risk Applications Applications that are described herein for any of these products are for illustrative purposes only NXP Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing or modification Limiting values Stress above one or more limiting values as defined in the Absolute Maximum Ratings System of IEC 60134 may cause permanent damage to the device Limiting values are stress ratings only and operation of the device at these or any other conditions above those given in the Characteristics sections of this document is not implied Exposure to limiting values for extended periods may affect device reliability Terms and conditions of sale NXP Semiconductors products are sold subject to the general terms and conditions of commercial sale as published at http www nxp com profile terms including those pertaining to warranty intellectual property rights infringement and limitation of liability unless explicitly otherwise agreed to in writing by NXP Semiconductors In case of any inconsistency or conflict between information in
29. ned to operate well with inductance values between 1 5 uH and 3 3 uH in order to optimize for solution size In a typical high current dual flash LED application a 2 2 uH inductance is recommended The inductors saturation current should be greater than or equal to the inductor peak current limiter current which is typical 2 2 A During normal operation it is recommended to keep the inductor peak current below this value The copper losses and magnetic hysteresis losses in the inductor also contribute to the total system losses Rectifier diode Selecting a Schottky diode with low forward voltage drop improves efficiency Although the average current through the diode is equal to the load current and independent on duty cycle for a boost converter topology it is recommended to select a diode with an average current rating that is significantly higher The peak current rating of the diode should be greater than the peak current through the inductor PCB layout It is essential to have a good circuit layout to maximize efficiency and minimize EMI disturbance Because the circuit topology uses an inductor it is often appointed as a main source for EMI disturbance But any loop of wire carrying a current is essentially an electromagnet with a field strength that is proportional to the current Therefore careful circuit layout is important keeping loop areas small and minimizing magnetic flux Due to the way an asynchronous boost converter operat
30. onal description of the SSL3250A Standby Indicator 1 Torch Flash Torch Indicator 014aaa294 8 2 2 Using the I C control SSL3250A 5 Using the 12C mode enables additional features and settings as described in the 12C register set see Table 6 The 12C mode has the same operational modes as described in Section 8 2 1 Figure 4 The Flash mode is entered in two steps 1 Set the correct current and timing values in the current control and timing registers This arms the device for the required flash operation NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 6 of 26 NXP Semiconductors SS L3250A 8 3 8 3 1 8 3 2 8 3 3 SSL3250A 5 Photo flash dual LED driver 2 Trigger the Flash mode either by the hardware STRB pin or by the FLASH STRB bit in the Flash strobe register 02h When the external strobe pin is not used it should be connected to GND to prevent false strobing of the main LED The external current setting resistor R_FL can still be used in Flash mode but is not required When the external current setting resistor R FL is not used the pin should preferably be connected to VIN this way a default resistor value of approximately 50 kO is assumed The current setting resistors for the indicator LED R IND and for the Torch mode R TR have no function in IC mode and the pins should preferably be connected to VIN Operationa
31. orch mode Flash mode The first mode is entered by putting a LOW level on the activate pin ACT This pin is common for both interface modes The operational modes Torch and Flash apply to the same main LED current source and the Indicator mode applies to a separate indicator LED current source Only when the 12C interface mode is enabled the operational modes Indicator Flash and or Torch can be used in parallel In normal operation the regulated converter uses Pulse Width Modulation PWM so the switching frequency is constant in all modes In applications where the required main LED voltage is lower than the applied input voltage the converter switches to linear mode The excess voltage difference between the required LED voltage and the input voltage is now compensated by increasing the voltage over the current sink and therefore on the LED pin Apart from the main LED s a separate indicator LED can be driven from the SSL3250A This indicator LED is driven by a linear current sink circuit that operates independently from the switch mode converter for the main LED s Interface modes The device is equipped I2C mode and Direct enable mode interfaces Which interface mode is used is defined by the level of the IF SEL pin at the start up of the device Vacr LOW to HIGH The state of the IF SEL pin should be kept static after powering up the device Table 4 shows the interface possibilities Table 4 Interface modes IF_S
32. pt on the INT line nor is it flagged in the status register 03h Soft start To avoid battery overloading when entering the Torch mode or the Flash mode the device is equipped with a soft start circuit This circuit limits the rate of rise of the LED current to 4 5 mA us until the required LED current has been reached When the device ends Flash mode or Torch mode the LED current decreases with a controlled slope of 9 mA us Whenever a protection is activated the LED current decreases without the controlled slope and drops immediately to zero Peak current limit To avoid saturation of the inductor the device is equipped with a peak current limit function This circuit limits the peak inductor currents to 2 2 A No protection is activated I C bus protocol The I C interface is a 2 wire serial interface developed by NXP Semiconductors to communicate between different ICs or modules The two wires are an SDA wire and an SCL wire Both lines must be connected to a positive supply via a pull up resistor when NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 14 of 26 NXP Semiconductors SS L3250A SSL3250A 5 Photo flash dual LED driver connected to the output stages of a device Data transfer may only be initiated when the bus is not busy The SSL3250A I C bus characteristic is according to the 400 kbit s Fast mode I C from the I C bus specification Remark For more details on the I2C
33. revious timed flash period has expired Flash mode during RF transmit Although the driver is not equipped with a separate TXMASK pin the device can operate like that to lower the current in the main LED in Flash mode during an RF transmission in a mobile phone application An external switch can be connected to the resistor controlling the nominal current value for the Flash mode By lowering the current in the main LED the inductor current and therefore the current drawn from the battery will be lowered Reducing the inductor current has to be fast because the inductor current is reduced within 50 us after changing the nominal current level to a lower setting At the end of the transmission period the main LED current can be increased again to the nominal current level A soft start circuit will increase the inductor current with a limited slope as defined by the soft start settings See Section 8 5 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 10 of 26 NXP Semiconductors SS L3250A 8 3 7 SSL3250A 5 Photo flash dual LED driver Average inductor t lt 50 us current TxMask S ff LE JL i Flash 014aaa296 Fig9 The inductor current during TxMask Indicator LED The indicator LED is connected between the Vpgar and the dedicated indicator LED current input pin Internally a linear current sink controls the indicator LED current to reach the required
34. setting equation for IC while Figure 6 illustrates the Torch mode current setting equation for the Direct enable mode 200 ILED mA 150 100 50 0 0 1 3 5 7 9 11 Register Torch current using 12C mode value 014aaa364 Fig 5 Torch mode LED current in IC mode 250 200 ILED mA 150 125 100 50 0 125 50 31 3 Register Torch current using direct control mode value kQ 014aaa365 Fig 6 Torch mode LED current in Direct enable mode NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 8 of 26 NXP Semiconductors SS L3250A Photo flash dual LED driver 8 3 4 Flash mode SSL3250A 5 The Flash mode allows the main LED to be used at high LED current setting The Flash mode current can be set up to 500 mA in both the I2C and Direct enable mode In I2C mode the current is defined by entering a value between a minimum of 12 and a maximum of 31 in the current control register The external resistor R_FL can be used to scale down the set current This can be used in the application to enable TxMasking as described in Section 8 3 6 The current in the main LED is defined using Equation 3 When not using the R_FL resistor assume a resistor value of 50 kQ in the equation Entering Flash mode can be done either by using the STRB pin or the FL
35. sh operation up to 820 ms I2C bus programmable up to 400 kHz Strobe signal to avoid I C latency for flash Discrete enable signals for stand alone operation Optional resistor configurable output currents Fast response to accommodate external TxMasking functionality Soft start in Torch and Flash modes to avoid battery overloading Integrated protection circuits for enhanced system reliability Internal time out function OverTemperature Protection OTP UnderVoltage LockOut UVLO OverVoltage Protection OVP Output current protection Interrupt signaling to system controller W Low device shut down current less than 1 pA WB SOT758 3 thermally enhanced 16 terminal HVQFN package founded by Philips NXP Semiconductors SSL3250A Photo flash dual LED driver 3 Applications W White LED driver for battery powered portable devices W Photo flash LED driver for mobile phones and digital cameras 4 Ordering information 4 1 5 Marking Table 1 Ordering information Type number Package Name Description Version HVQFN16 plastic thermal enhanced very thin quad flat package SOT758 3 no leads 16 terminals body 3 x 3 x 0 85 mm SSL3250AHN C1 Ordering options Table 2 Ordering options Type number Orderable part number Pin 1 indicator location for tape and reel SSL3250AHN C1 SSL3250AHN C1 528 Pin 1 in quadrant 2 See Figure 1 SSL3250A 5 e o
36. so during the soft start phase of the flash period The short circuit protection may also be triggered when either the inductor or the diode is not connected Also a shorted diode may trigger the output short protection if two LEDs are connected in series between VO and LED pins Therefore little or no current will flow through the LEDs or into the LED pin and Vi gp will stay almost at GND level When an overvoltage is encountered the OS PROT flag bit 3 is set in the status register Remark If Vgar is HIGH and only one White LED is connected between VO and LED pins the Schottky diode may be irreversibly damaged when the LED pin is shorted This is inherent to the asynchronous boost converter topology Interrupt line The interrupt pin INT is an active LOW open drain output allowing for multiple devices to be connected as a wired OR using the same interrupt line to the external control logic On the interrupt line only one pull up resistor is needed in the complete system Undervoltage lockout As a result of a low battery voltage the input voltage can drop too low to guarantee normal operation When the input voltage has dropped below the undervoltage lockout level the device switches to an undervoltage lockout state stopping all operations of the device Start up is only possible by crossing the start up level again Recovering from this error results in the loss of all register settings This protection does not generate an interru
37. t voltage on pin VO ILED LED current IF_SEL 0 current control register 08h STRB 0 IF_SEL 0 current control register 30h STRB 0 IF_SEL 0 current control register COh STRB 1 IF_SEL 0 current control register F8h STRB 1 default flash current IF_SEL 1 EN1 1 EN2 1 R FL HIGH default torch current IF SEL 1 EN1 0 EN2 1 R TR HIGH lleak LED leakage current on pin LED ACT 0 Shut down mode ViED voltage on pin LED Boost mode lj gp 0 5 A Follower mode Vovp overvoltage protection voltage Indicator LED parameters Min Typ Max Unit 40 50 60 mA 106 125 144 mA 356 395 435 mA 450 500 550 mA 450 500 550 mA 106 125 144 mA 300 E mV 350 mV 9 8 10 5 11 0 V lj IND current on pin IND IF SEL 0 I2C 2 5 17 5 mA IF SEL 1 direct enable 2 5 x 20 mA default indicator current 10 mA IF SEL 1 EN1 1 EN2 0 R IND HIGH Ali IND current variation on pin IND 15 lleak I_IND leakage current on pin IND ACT 0 Shut down mode 1 uA Power MOSFET Rpson drain source on state resistance NFET 200 425 mW Timing fsw switching frequency 1 08 1 2 1 32 MHz max maximum duty cycle 82 96 tstart soft soft start time ACT 0 to ACT 1 160 400 us response time tro ace accuracy of time out time the absolute value can be 10 10 set with IC SSL3250A 5 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 2
38. this document and such terms and conditions the latter will prevail No offer to sell or license Nothing in this document may be interpreted or construed as an offer to sell products that is open for acceptance or the grant conveyance or implication of any license under any copyrights patents or other industrial or intellectual property rights Export control This document as well as the item s described herein may be subject to export control regulations Export might require a prior authorization from national authorities 16 4 Trademarks Notice All referenced brands product names service names and trademarks are the property of their respective owners I C bus logo is a trademark of NXP B V For more information please visit http www nxp com For sales office addresses please send an email to salesaddresses nxp com SSL3250A 5 NXP B V 2009 All rights reserved Product data sheet Rev 05 16 December 2009 25 of 26 NXP Semiconductors SSL3250A 18 Contents Photo flash dual LED driver oO NN po e L 8 2 8 2 1 8 2 2 8 3 8 3 1 8 3 2 8 3 3 8 3 4 8 3 5 8 3 6 8 3 7 8 4 8 4 1 8 4 2 8 4 3 8 4 4 8 4 5 8 4 6 8 5 8 6 8 7 8 7 1 8 7 2 8 7 3 9 1 9 2 9 3 9 4 9 5 10 11 12 General description use 1 Features 2 x RR 1 Applications sor rr nen 2 Ordering information see 2 Order
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