19-6278; Rev 0; 5/12
E V A L U A T I O N K I T A V A I L A B L E
MAX98355A/MAX98355B
PCM Input Class D Audio Power Amplifiers
General Description
Features
The MAX98355A/MAX98355B are digital pulse-code
modulation (PCM) input Class D power amplifiers that
provide Class AB audio performance with Class D effi-
ciency. These ICs offer five selectable gain settings
(3dB, 6dB, 9dB, 12dB, and 15dB) set by a single gain-
select input (GAIN).
S Single-Supply Operation (2.5V to 5.5V)
S 3.2W Output Power into 4I at 5V
S 2.2mA Quiescent Current
S 92% Efficiency (R = 8I, P
= 900mW,
L
OUT
V
DD
= 3.7V)
The digital audio interface is highly flexible with the
MAX98355A supporting I2S data and the MAX98355B
supporting left-justified data. Both ICs support time divi-
sion multiplexed (TDM) data. The digital audio interface
accepts sample rates ranging from 8kHz to 96kHz for all
supported data formats. The ICs can be configured to
produce a left channel, right channel, or (left + 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 data with up to four slots when 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 addi-
tion to reducing the size and pin count of the ICs.
S 25µV
Output Noise (A = 15dB)
V
RMS
S Low 0.013% THD+N at 1kHz
S No MCLK Required
S Sample Rates of 8kHz to 96kHz
S Supports Left, Right, or (Left + Right)/2 Outputs
S Sophisticated Edge Rate Control Enables
Filterless Class D Outputs
S 77dB PSRR at 217Hz
S Low RF Susceptibility Rejects TDMA
Noise from GSM Radios
The ICs also feature a very high wideband jitter tolerance
(12ns typ) on BCLK and LRCLK to provide robust operation.
S Extensive Click-and-Pop Reduction Circuitry
S Robust Short-Circuit and Thermal Protection
Active emissions-limiting, edge-rate limiting, and over-
shoot 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.
S Available in Space-Saving Package:
1.345mm x 1.435mm WLP (0.4mm Pitch)
The ICs are available in a 9-pin WLP package (1.345mm
x 1.435mm x 0.64mm) and are specified over the -40NC
to +85NC temperature range.
Simplified Block Diagram
Applications
Cellular Phones
Tablets
SHUTDOWN
AND
CHANNEL
SELECT
GAIN
CONTROL
MAX98355A
MAX98355B
Portable Media Players
Notebook Computers
CLASS D
OUTPUT
STAGE
DIGITAL
AUDIO
INTERFACE
PCM
INPUT
Ordering Information appears at end of data sheet.
Functional Diagram appears at end of data sheet.
DAC
For related parts and recommended products to use with this part,
refer to www.maxim-ic.com/MAX98355A.related.
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1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.