Click here for production status of specific part numbers. Evaluates: MAX98357A/MAX98357B MAX98357 Evaluation System (TQFN) (TQFN) General Description Features The MAX98357 development board (DEV board) is a fully 2.5V to 5.5V Single-Supply Operation assembled and tested PCB that evaluates the MAX98357 Only a Single External Component (VDD Capacitor) 2 I S digital input Class D power amplifier. The DEV board Required in Many Applications operates from a single 2.5V to 5.5V DC power supply and 2 I S, Left-Justified, or TDM Input is capable of delivering 3.2W into a 4 load. The device Five Selectable Gains (3db, 6dB, 9dB, 12dB, and outputs can be connected directly to a speaker load for filterless applications. However, a filter can be added to 15dB) 2 ease evaluation. The MAX98357A accepts standard I S Audio Channel Select (Left, Right, and Mono Mix) data and the MAX98357B accepts left-justified digital Filterless Operation audio data. Both versions also support 8-channel TDM Optional Class D Output Filters for Ease of audio data. Evaluation The MAX98357 evaluation system (EV system) includes Proven PCB Layout the MAX98357 DEV board and Maxim Integrateds audio interface board (MAXAUDINT001 ). Fully Assembled and Tested The MAXAUDINT001 board provides an easy-to-use 2 USB audio-to-I S converter. This allows for any computer to become a digital audio source, which can be used to Ordering Information appears at end of data sheet. evaluate the devices. The MAXAUDINT001 board can also be used to power the MAX98357. This allows for a complete evaluation from a single USB connection. 2.5V TO 5.5V 10F 0.1F VDD GAIN PCM MAX98357 LRCLK AUDIO BCLK OUTP DIGITAL INTERFACE CLASS D AUDIO DAC DIN BOARD OUTPUT STAGE INTERFACE OUTN SD MODE Figure 1. Simplified Block Diagram 19-6843 Rev 3 9/18Evaluates: MAX98357A/MAX98357B MAX98357 Evaluation System (TQFN) (TQFN) Quick Start Detailed Description of Hardware The MAX98357 EV system is designed to allow a Recommended Equipment 2 thorough evaluation of the MAX98357 I S digital input MAX98357 EV system Class D power amplifier. The DEV board can be used by 2.5V to 5.5V, 2A DC power supply itself as a stand-alone evaluation board and driven directly by audio test equipment. The DEV board can also be used USB audio source (from computer through an audio in conjunction with the MAXAUDINT001 board, which media player such as iTunes or Windows Media 2 allows for any computer to become an I S digital audio player) source. 4 or 8 speaker The MAXAUDINT001 board has DC regulators that can Procedure be used to power the device. This allows for quick evalu- The EV system is fully assembled and tested. Follow the ation from a single USB connection. Note that powering steps below to verify board operation. Caution: Do not the device from the MAXAUDINT001 board does not turn on the power supply until all connections are allow for high-power evaluation as the input current is lim- completed. ited and evaluation with a speaker is not recommended. Jumpers JU4 and JU6 are used to power the device from 1) On the DEV board verify that headers and switches the MAXAUDINT001 board or external supplies con- are configured as follows: nected to test points VIN and VDDIO on the DEV board. JU2: Pins 1-3 (selects left channel) The DEV board operates from a single 2.5V to 5.5V DC JU4: Pins 1-2 (power routed from the MAXAUDINT001 power supply and is capable of delivering 3.2W into a 4 board) load and 1.75W into an 8 load. The device outputs can JU5: Pins 1-5 (12dB gain) be connected directly to a speaker for filterless applica- JU6: Pins 2-3 (power routed from external supply) tions. However, a filter can be added to ease evaluation. The LRC components needed for evaluation of a filtered SW1: Position 1-2 (part is on) output are included with the EV kit. The MAX98357A 2) Set the power-supply output to 5V. Disable the power 2 accepts standard I S data and the MAX98357B accepts supply. left-justified digital audio data. Both versions also support 3) Connect the power-supply ground terminal to GND 8-channel TDM audio data. and the power-supply positive terminal to VIN on the Filterless Output DEV board. The DEV board filterless outputs (OUTP, OUTN) can be 4) With the audio source disabled, connect the USB connected directly to a speaker load without any filter- audio source to the USB AUDIO port (USB2) on the ing. Use the OUTP and OUTN test points to connect the MAXAUDINT001 board. speaker directly to the device output. 5) Connect the MAXAUDINT001 board to J1 on the DEV Filtered Output board. Audio analyzers typically cannot accept the Class D 6) Connect the speaker across the OUTP and OUTN test amplifiers pulse-width modulated (PWM) signals at their points. inputs. Therefore, the DEV board features optional low- 7) Enable the power-supply output. pass filters at the outputs to ease evaluation. As shipped, 8) Enable the audio source. the DEV boards lowpass filter LRC components are unpopulated and L1, L2 are shorted on the PCB. 9) Verify that the speakers are playing the audio source signal. To use the filtered output posts (FOUTP, FOUTN), remove the shorts on L1 and L2 and install components L1, L2, C3C7, and R5, R6. Use the output posts to connect the filtered outputs to the audio analyzer. The default lowpass filters at the DEV board output are optimized for a 4 speaker. iTunes is a registered trademark of Apple Inc. Windows Media is registered trademark and registered service mark of Microsoft Corporation. Maxim Integrated 2 www.maximintegrated.com