Filterless High Efficiency

Mono 3 W Class-D Audio Amplifier

Preliminary Technical Data

SSM2375

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FEATURES

Filterless Class-D

r with spread-spectrum Σ-∆

modulation

3 W into 3 Ω load and 1.4 W into 8 Ω load at 5.0 V supply with

<1% total harmonic distortion (THD)

93%

cy at 5.0 V, 1.4 W into 8 Ω speaker

>100 dB signal-to-noise ratio (SNR)

High PSRR @ 217 Hz: 80dB

Flexible gain adjustment pin: 0dB to 12dB in 3dB steps

Fixed Input Impedance, 80kΩ

User-selectable ultralow EMI emissions mode

Single-supply operation from 2.5 V to 5.5 V

20 nA shutdown current

Short-circuit and thermal protection with auto recovery

Available in 9-ball, 1.5 mm × 1.5 mm WLCSP

Pop-and-click suppression

APPLICATIONS

Mobile phones

MP3 players

Portable electronics

GENERAL DESCRIPTION

SM2375 is a fully integrated, high e ciency Class-D

audio ampli er. It is designed to maximize performance for

mobile phone applications. e 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 an 3 Ω load

from a 5.0 V supply.

SM2375 features a high e ciency, low noise modulation

scheme that requires no external LC output lt

modulation operates with high e ciency even at low output

power. It operates with 93% e ciency at 1.4 W into 8 Ω or 85%

e ciency at 3 W into 3 Ω from a 5.0 V supply and has an SNR

of >100 dB.

Spread-spectrum pulse density modulation (PDM) is used to

provide lower EMI-radiated emissions compared with other

Class-D architectures.

e inherent randomized nature of

spread-spectrum PDM eliminates clock intermodulation

(beating e ect) of several ampli ers in close proximity.

SM2375 includes an optional modulation select pin

(ultralow EMI emission mode) that signi cantly reduces the

radiated emissions at the Class-D outputs, particularly above 100

MHz and can pass FCC Class B radiated emissions testing with

50cm unshielded speaker cable without any external ltering.

evice also includes a highly exible gain select pin that

only requires one series resistor in order to select between 0dB,

3dB, 6dB, 9dB, or 12dB.

e bene t of this is to improve gain

matching between multiple SSM2375 devices within a single

application as compared to using external resistors to set gain.

SM2375 has a micropower shutdown mode with a typical

shutdown current of 20 nA. Shutdown is enabled by applying a

logic low to the SD pin.

device also includes pop-and-click suppression circuitry.

minimizes voltage glitches at the output during turn-on and

turn-o , reducing audible noise on activation and deactivation.

Other included features to simplify system level integration of the

SSM2375 are input low pass ltering to suppress out of band DAC

noise interference to the PDM modulator and xed input

impedance to simplify component selection across multiple

platform production builds.

SM2375 is speci ed over the industrial temperature range

of −40°C to +85°C. It has built-in thermal shutdown and output

short-circuit protection. It is available in a halogen-free 9-ball,

1.5 mm × 1.5 mm wafer level chip scale package (WLCSP).

Rev. PrC