Tiny, Low-Cost, PCM Class D Amplifier with Class AB Performance

Supports I2S and 8-Channel TDM Data

Please check latest availability status for a specific part variant.


The MAX98357A/MAX98357B is an easy-to-use, low-cost, digital pulse-code modulation (PCM) input Class D amplifier that provides industry-leading Class AB audio performance with Class D efficiency. The digital audio interface automatically recognizes up to 35 different PCM and TDM clocking schemes which eliminates the need for I2C programming. Operation is further simplified by eliminating the need for an external MCLK signal that is typically used for PCM communication. Simply supply power, LRCLK, BCLK, and digital audio to generate audio! Furthermore, a novel pinout allows customers to use the cost-effective WLP package with no need for expensive vias (refer to Application Note 6643: Optimize Cost, Size, and Performance with MAX98357 WLP for more information).

The digital audio interface is highly flexible with the MAX98357A supporting I2S data and the MAX98357B supporting left-justified data. Both ICs support 8 channel time division multiplexed (TDM) data. The digital audio interface accepts specified sample rates between 8kHz and 96kHz for all supported data formats. The ICs can be configured to produce a left channel, right channel, or (left/2 + right/2) output from the stereo input data. The ICs operate using 16/24/32-bit data for I2S and left-justified modes as well as 16-bit or 32-bit data using TDM mode. The ICs eliminate the need for the external MCLK signal that is typically used for PCM communication. This reduces EMI and possible board coupling issues in addition to reducing the size and pin count of the ICs.

The ICs also feature a very high wideband jitter tolerance (12ns typ) on BCLK and LRCLK to provide robust operation.

Active emissions-limiting, edge-rate limiting, and overshoot control circuitry greatly reduce EMI. A filterless spread-spectrum modulation scheme eliminates the need for output filtering found in traditional Class D devices and reduces the component count of the solution.

The ICs are available in 9-pin WLP (1.345mm x 1.435mm x 0.64mm) and 16-pin TQFN (3mm x 3mm x 0.75mm) packages and are specified over the -40°C to +85°C temperature range.

PCM Class D Amplifier with Class AB performance Functional Diagram MAX98357A/B MAX98357A, MAX98357B: Functional Diagram Enlarge+

Key Features

  • Single-Supply Operation (2.5V to 5.5V)
  • 3.2W Output Power into 4Ω at 5V
  • 2.4mA Quiescent Current
  • 92% Efficiency (RL = 8Ω, POUT = 1W)
  • 25µVRMS Output Noise (AV = 15dB)
  • Low 0.015% THD+N at 1kHz
  • No MCLK Required
  • Sample Rates of 8kHz to 96kHz
  • Supports Left, Right, or (Left/2 + Right/2) Output
  • Sophisticated Edge Rate Control Enables Filterless Class D Outputs
  • 77dB PSRR at 1kHz
  • Low RF Susceptibility Rejects TDMA Noise from GSM Radios
  • Extensive Click-and-Pop Reduction Circuitry
  • Robust Short-Circuit and Thermal Protection
  • Available in Space-Saving Packages: 1.345mm x 1.435mm WLP (0.4mm Pitch) and 3mm x 3mm TQFN
  • Solution Size with Single Bypass Capacitor is4.32mm2


  • Cellular Phones
  • Notebook and Netbook Computers
  • Tablets
Part NumberClassSpkr. Amp. VCC
Spkr. Amp. VCC
Spkr. Amp. ICC
POUT into 4Ω @ 1% THD+N
POUT into 4Ω @ 10% THD+N
POUT into 8Ω @ 1% THD+N
POUT into 8Ω @ 10% THD+N
Spkr. Amp. Half Pwr. THD+N
minmaxtypminminminminA- WeightedminSee Notes
MAX98357B D2.
$0.87 @1k
See All Speaker Amplifiers (32)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX98357DEV#WLP: Evaluation System for the MAX98357A and MAX98357B (WLP)
MAX98357EVSYS#WLP: Evaluation System for the MAX98357A and MAX98357B (WLP)
MAX98357DEV#TQFN: Evaluation System for the MAX98357A and MAX98357B (TQFN)
MAX98357EVSYS#TQFN: Evaluation System for the MAX98357A and MAX98357B (TQFN)
MAXAUDINT001: Evaluation Kit for the MAXQ2000/MAX98357A/MAX98357B/MAX98358 and MAX98371
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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