Evaluation Board User Guide
Contents
1. 0 Page 7 of 8 Figure 7 Bottom Layer Copper GAIN gt ANALOG H3 DEVICES HI ACTIVE m 39 2 EVAL 55M23757 REV1 1 Spec No P 030386 Figure 8 Top Silkscreen tie tu Cx ii EL aa b Figure 9 Bottom Silkscreen 09393 007 09393 008 09393 009 ORDERING INFORMATION BILL OF MATERIALS Table 4 Qiy _ Reference Designator Supplier Part No C3 C4 C5 C6 C7 B1 B2 R1 R2 R3 H1 H4 H5 J1 to J3 H2 H3 Qi NNN NO IC SSM2375 Capacitor 22 nF 25 V 10 X7R 0805 Capacitor ceramic 0 1 uF 50 V Y5V 0603 Capacitor ceramic 10 uF 10 V X5R 0805 Capacitor 47 uF 25 V electrolytic Capacitor ceramic 510 pF 50 V 296 0603 Wire short Resistor 0 0 O 1 8 W 0805 Resistor 47 kO 1 10 W 196 0603 Connector header 2 position 0 100 single gold Connector header 4 position 0 100 single gold Connector header 3 position 0 100 single gold Analog Devices SSM2375CBZ Panasonic ECJ 2YB1E224K Panasonic ECJ 1VF1H104Z Murata GRM21BR61A106KE19L Nichicon UFW1E470MDD Murata GRM1885C1H511JA01D N A Panasonic PO 0OATR ND Panasonic ERJ 3EKF4702V Tyco 826629 2 Tyco 826629 3 Tyco 826629 4 ESD Caution ESD electrostatic discharge sensitive device Charged devices and circuit boards can discharge without detection Although this product features patented or proprietary protection Alas circuitry damage may occur on devices subjecte2. B2 terminals to make a direct connection from device output to the H5 speaker header Connect the load to the audio output connector H5 Connect the audio input to the board in either differential mode or single ended mode depending on the application Connect the power supply with the proper polarity and voltage Rev 0 Page 5 of 8 WHAT TO TEST Electromagnetic interference EMI connect wires for the speakers making sure they are the same length as the wires required for the actual application environment then complete the EMI test Signal to noise ratio Output noise make sure to use an A weighted filter to filter the output before reading the measurement meter Maximum output power Distortion Efficiency EVALUATION BOARD SCHEMATIC AND ARTWORK 00 E6E60 ad eX LHOH V ecS809 LZdlN 708 cd 4do1g dOdON ZO oX LYCH O SH 0 LnO 4do1g 99 dOdON WecSs809lZdi iaous Id uno 0 01009 X tYadH I eNom OOQ ad GZEZINSS LN jnr 0 EJ ad CX LHOH WHqvsH WuMod LH ad ALV eX LHOH er T L T Ano 10d dV GD vO dodou TH zeou otoubnodu3 oes UNTY anzz cX LHOH HP e HAT LOW ed ad jnec 0 ld VX lLYCH jnec 0 cH IO Figure 3 Schematic of the SSM2375 Evaluation Board Rev 0 Page 6 of 8 Figure 6 Third Layer Copper VDD Plane 09393 005 09393 004 09393 006 Rev
3. small enough to reject unnecessary extremely low frequency signals For music signals the cutoff frequency is typically between 20 Hz and 30 Hz The value of the input capacitor is calculated by C l 2nRm f where Rmi 80 kQ R1 or R2 fcis the desired cutoff frequency Output Ferrite Beads B1 and B2 The output beads B1 and B2 are necessary components for filtering out the EMI caused at the switching output nodes when the length of the speaker wire is greater than 10 cm The penalty for using ferrite beads for EMI filtering is slightly worse noise and distortion performance at the system level due to the nonlinearity of the beads Ensure that these beads have enough current conducting capability while providing sufficient EMI attenuation The current rating needed for an 8 Q load is approximately 420 mA and impedance at 100 MHz should be 2120 Q In addition the lower the dc resistance DCR of these beads the better for minimizing their power consumption Table 2 describes the recommended beads Rev 0 Page 3 of 8 Output Shunting Capacitors Output Inductors There are two output shunting capacitors C6 and C7 that work If inductors are preferred for EMI filtering at the output nodes with the ferrite beads B1 and B2 Use small size 0603 or 0402 choose components with an inductance of less than 2 2 uH multilayer ceramic capacitors made of X7R or COG NPO The higher the inductance the lower the EMI is at the out
4. ANALOG DEVICES Evaluation Board User Guide UG 196 One Technology Way P O Box 9106 Norwood MA 02062 9106 U S A Tel 781 329 4700 Fax 781 461 3113 www analog com Evaluation Board for SSM2375 Filterless Class D Audio Amplifier PACKAGE CONTENTS EVAL SSM2375Z evaluation board OTHER SUPPORTING DOCUMENTATION SSM2375 data sheet GENERAL DESCRIPTION The SSM2375 is a fully integrated high efficiency Class D audio amplifier It is designed to maximize performance for mobile phone applications The application circuit requires a minimum of external components and operates from a single 2 5 V to 5 5 V supply It is capable of delivering 3 W of continuous output power with less than 1 THD N driving a 3 O load from a 5 0 V supply Spread spectrum pulse density modulation PDM is used to provide lower EMI radiated emissions compared with other Class D architectures The inherent randomized nature of spread spectrum PDM eliminates clock intermodulation beating effect of several amplifiers in close proximity The SSM2375 includes an optional modulation select pin that 09393 001 Figure 1 SSM2375 Evaluation Board Top View PLEASE SEE THE LAST PAGE FOR AN IMPORTANT WARNING AND LEGAL TERMS AND CONDITIONS enables a low EMI mode which significantly reduces the radiated emissions at the Class D outputs particularly above 100 MHz With this option selected the SSM2375 can pass FCC Class B radiated emissions testin
5. IDED AS IS AND ADI MAKES NO WARRANTIES OR REPRESENTATIONS OF ANY KIND WITH RESPECT TO IT ADI SPECIFICALLY DISCLAIMS ANY REPRESENTATIONS ENDORSEMENTS GUARANTEES OR WARRANTIES EXPRESS OR IMPLIED RELATED TO THE EVALUATION BOARD INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTY OF MERCHANTABILITY TITLE FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS IN NO EVENT WILL ADI AND ITS LICENSORS BE LIABLE FOR ANY INCIDENTAL SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES RESULTING FROM CUSTOMER S POSSESSION OR USE OF THE EVALUATION BOARD INCLUDING BUT NOT LIMITED TO LOST PROFITS DELAY COSTS LABOR COSTS OR LOSS OF GOODWILL ADI S TOTAL LIABILITY FROM ANY AND ALL CAUSES SHALL BE LIMITED TO THE AMOUNT OF ONE HUNDRED US DOLLARS 100 00 EXPORT Customer agrees that it will not directly or indirectly export the Evaluation Board to another country and that it will comply with all applicable United States federal laws and regulations relating to exports GOVERNING LAW This Agreement shall be governed by and construed in accordance with the substantive laws of the Commonwealth of Massachusetts excluding conflict of law rules Any legal action regarding this Agreement will be heard in the state or federal courts having jurisdiction in Suffolk County Massachusetts and Customer hereby submits to the personal jurisdiction and venue of such courts The United Nations Convention on Contracts for the International Sale of Goods shall not
6. able 3 for recommendations For optimal THD and SNR performance as specified in the SSM2375 data sheet remove the entire EMI filter short across the ferrite bead terminals and open the capacitor terminals POWER SUPPLY CONFIGURATION The 2 pin header H1 is used to power the board Care must be taken to connect the dc power with correct polarity and voltage Reverse polarity or overvoltage may damage the board perma nently The maximum supply current is approximately 0 33 A when driving an 8 O load and when the input voltage is 5 V Do not allow VDD to exceed 5 5 V COMPONENT SELECTION Selecting the proper components is the key to achieving the performance required at the cost budgeted Input Gain Resistor Selection R1 and R2 If the desired gain must be adjusted beyond the available gain settings see the Gain Configuration section a series resistor can be placed in the input signal path This creates a voltage divider with the 80 kO input resistance on each input pin allowing an arbitrary reduction of the input signal Note that input signal attenuation directly reduces SNR performance therefore large values compared to the built in input resistance should be avoided These components are populated with 0 Q values on the evaluation board Input Coupling Capacitor Selection C1 and C2 The input coupling capacitors C1 and C2 should be large enough to couple the low frequency signal components in the incoming signal but
7. apply to this Agreement and is expressly disclaimed ANALOG DEVICES Rev 0 Page 8 of 8 2011 Analog Devices Inc All rights reserved Trademarks and registered trademarks are the property of their respective owners UG09393 0 4 11 0 www analog com
8. cing a jumper across two pins of H3 the amplifiers gain pin can be connected to GND or VDD Three jumper settings are used between the center pin and the left pin HI between the center pin and the right pin LO and no jumper open Placing a jumper on J3 removes the 47 KQ resistor R3 between the gain pin and H3 Gain settings between 0 dB and 12 dB are available see Table 1 for configuration details Table 1 Gain Configuration Gain LN NN Configuration 0 dB Short gain pin to GND 3 dB Gain pin unconnected 6 dB Short gain pin to VDD 9 dB Gain pin through 47 kO to GND 12 dB Gain pin through 47 kO to VDD OUTPUT CONFIGURATION The output connector H4 is located on the right side of the board see Figure 1 H4 can drive a loudspeaker whose impedance should be no less than 3 Q Because the S M2375 does not typically require any external LC output filters due to a low noise modulation scheme no output filter is installed on the evaluation board In this case thick wire connects the empty pads of B1 and B2 and the capacitor pads are left unpopulated If the speaker length exceeds 10 cm place Ferrite Bead B1 and Ferrite Bead B2 in the output paths and use Capacitors C6 and C7 to couple the output terminals to ground as shown in the schematic in Figure 3 Some recommended ferrite beads are listed in Table 2 Some users may want to use inductors for applications with specific EMI vs audio performance con straints see T
9. d to high energy ESD Therefore proper ESD precautions should be taken to avoid performance degradation or loss of functionality Legal Terms and Conditions By using the evaluation board discussed herein together with any tools components documentation or support materials the Evaluation Board you are agreeing to be bound by the terms and conditions set forth below Agreement unless you have purchased the Evaluation Board in which case the Analog Devices Standard Terms and Conditions of Sale shall govern Do not use the Evaluation Board until you have read and agreed to the Agreement Your use of the Evaluation Board shall signify your acceptance of the Agreement This Agreement is made by and between you Customer and Analog Devices Inc ADI with its principal place of business at One Technology Way Norwood MA 02062 USA Subject to the terms and conditions of the Agreement ADI hereby grants to Customer a free limited personal temporary non exclusive non sublicensable non transferable license to use the Evaluation Board FOR EVALUATION PURPOSES ONLY Customer understands and agrees that the Evaluation Board is provided for the sole and exclusive purpose referenced above and agrees not to use the Evaluation Board for any other purpose Furthermore the license granted is expressly made subject to the following additional limitations Customer shall not i rent lease display sell transfer assign sublicense or dis
10. g with a 50 cm unshielded speaker cable without any external filtering The device also includes a flexible gain select pin that only requires one series resistor to select among 0 dB 3 dB 6 dB 9 dB or 12 dB The benefit of this is to improve gain matching between multiple SSM2375 devices within a single application as compared to using external resistors to set gain This user guide describes how to configure and use the SSM2375 evaluation board It is recommended that this user guide be read in conjunc tion with the SSM2375 data sheet which provides specifications internal block diagrams and application guidance for the amplifier IC EVALUATION BOARD OVERVIEW The SSM2375 evaluation board carries a complete application circuit for driving a loudspeaker Figure 1 shows the top view of the evaluation board and Figure 2 shows the bottom view 09393 002 Figure 2 SSM2375 Evaluation Board Bottom View Rev 0 Page 1 of 8 TABLE OF CONTENTS Package Contents Other Supporting Documentation General Description Evaluation Board Overview Revision History sonete Setting Up the Evaluation Board Input Configuration Shutdown Mode Gain Configuration REVISION HISTORY 4 11 Revision 0 Initial Version Rev 0 Page 2 of 8 l OutPut COnN Anra O Mese E PE AA A 1 Power Su
11. pply Configuratio ete de t D ertet M M M 1 Component Selectl D ossi esi RERO EOD E o NT l Gerne Star teea enS acd eaten eran pad Pp cde 2 hri MI anvaaitaicneucinivicnvvauaiiannndnaviaenueues 3 Evaluation Board Schematic and Artwork PEE A EA EAT 3 Orderino Mior maoene acrem editos aac aa DON op Vsus ua en er ere 3 Bill Of Materials ec eun GORDON MED E eee 3 SETTING UP THE EVALUATION BOARD INPUT CONFIGURATION A 4 pin header H2 on the middle left side of the board feeds the audio signal into the board see Figure 1 If the input audio signal is differential IN and IN three pins of H2 are used for IN IN and signal ground For a single ended audio input only two pins of H2 are used One is for the signal ground and the other is for either IN or IN If IN is used place a jumper between Pin 3 and Pin 4 of H2 shorting IN to ground If IN is used place the jumper between Pin 1 and Pin 2 of H2 connecting IN to ground SHUTDOWN MODE The 2 pin header J1 is used to turn on and off the SSM2375 amplifier Placing a jumper across Pin 1 and Pin 2 of H1 puts the SSM2375 in normal operation Removing the jumper shuts down the SSM2375 so that only a minimum current about 20 nA is drawn from the power supply GAIN CONFIGURATION Two headers H3 and J3 control the SSM2375 analog gain By pla
12. put materials Note that the capacitors can be used in pairs a however cost and power consumption are higher Using 0 47 uH capacitor with small capacitance up to 100 pF plus a capacitor to 2 2 uH inductors is recommended and the current rating and with a larger capacitance less than 1 nF This configuration saturation current should exceed 600 mA for an 8 Q load provides thorough EMI reduction for the entire frequency Table 3 shows the recommended inductors spectrum If the bill of materials must be minimized a single capacitor of approximately 470 pF can be used with acceptable performance in many cases Table 2 Recommended Output Beads Part No Manufacturer Z G WwkimA OR Size mm BLM18PG121SN1D Murata 120 1 6 x 0 8 x 0 8 MPZ16085101A TDK 100 1 6 x 0 8 x 0 8 MPZ16085221A TDK 220 1 6 x 0 8 x 0 8 BLM18EG221SN1D Murata 220 1 6 x 0 8 x 0 8 Table 3 Recommended Output Inductors Part No Manufacturer LUM lwximA ORO Size imm LQM31PNR47M00 Murata 3 2 x 1 6 x 0 85 LOM31PN1ROMOO Murata 3 2 x 1 6 x 0 85 LOM21PNR47MCO Murata 2 0 x 1 25 x 0 5 LOM21PN1ROMCO Murata 2 0 x 1 25 x 0 5 LQH32CN2R2M53 Murata 3 2x 2 5 x 1 55 Rev 0 Page 4 of 8 GETTING STARTED To ensure proper operation carefully follow Step 1 through Step 5 l Place a jumper between Pin 1 and Pin 2 of J1 to enable the amplifier For most audio quality testing the EMI filtering B1 B2 and C6 C7 must be removed Short across the B1 and
13. tribute the Evaluation Board and ii permit any Third Party to access the Evaluation Board As used herein the term Third Party includes any entity other than ADI Customer their employees affiliates and in house consultants The Evaluation Board is NOT sold to Customer all rights not expressly granted herein including ownership of the Evaluation Board are reserved by ADI CONFIDENTIALITY This Agreement and the Evaluation Board shall all be considered the confidential and proprietary information of ADI Customer may not disclose or transfer any portion of the Evaluation Board to any other party for any reason Upon discontinuation of use of the Evaluation Board or termination of this Agreement Customer agrees to promptly return the Evaluation Board to ADI ADDITIONAL RESTRICTIONS Customer may not disassemble decompile or reverse engineer chips on the Evaluation Board Customer shall inform ADI of any occurred damages or any modifications or alterations it makes to the Evaluation Board including but not limited to soldering or any other activity that affects the material content of the Evaluation Board Modifications to the Evaluation Board must comply with applicable law including but not limited to the RoHS Directive TERMINATION ADI may terminate this Agreement at any time upon giving written notice to Customer Customer agrees to return to ADI the Evaluation Board at that time LIMITATION OF LIABILITY THE EVALUATION BOARD PROVIDED HEREUNDER IS PROV
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