Analog Devices SSM2304 Preliminary Technical Data

Preliminary Technical Data

FEATURES

Filterless Class-D amplifier with built-in output stage
2 W into 4 Ω and 1.2 W into 8 Ω at 5.0 V supply with less than
10% THD
85% efficiency at 5.0 V, 2W into 4 Ω speaker
Better than 95dB SNR (signal-to-noise ratio)
Available in 16-lead 3 mm × 3 mm LFCSP
Single-supply operation from 2.2 V to 5.0 V
20 nA ultralow shutdown current
Short-circuit and thermal protection
Pop-and-click suppression
Built-in resistors reduce board component count
Default fixed 18dB gain and user-adjustable

APPLICATIONS

Notebooks and PCs
Mobile phones
MP3 players
Portable gaming
Portable electronics
Educational toys

GENERAL DESCRIPTION

The SSM2304 is a fully integrated, high efficiency, Class-D stereo
audio amplifier. It is designed to maximize performance for
portable applications. The application circuit requires a
minimum of external components and operates from a single
2.2 V to 5.0 V supply. It is capable of delivering 2 W of con-
tinuous output power with less than 10% THD + N driving a
4 Ω load from a 5.0 V supply.
Rev. PrD
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2 W Filterless Class-D
Stereo Audio Amplifier
The SSM2304 features a high efficiency, low noise modulation
scheme. It operates with 85% efficiency at 2 W into 4 Ω from a
5.0 V supply and has a signal-to-noise ratio (SNR) that is better
than 95 dB. PDM modulation is used to provide lower EMI-
radiated emissions compared with other Class-D architectures.
The SSM2304 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.
The architecture of the device allows it to achieve a very low level
of pop and click. This minimizes voltage glitches at the output
during turn-on and turn-off, thus reducing audible noise on
activation and deactivation.
The fully differential input of the SSM2304 provides excellent
rejection of common-mode noise on the input. Input coupling
capacitors can be omitted if the dc input common-mode voltage
is approximately V /2.
DD
The SSM2304 also has excellent rejection of power supply noise,
including noise caused by GSM transmission bursts and RF
rectification. PSRR is typically 70 dB at 217 Hz.
The gain can be set to 6 dB or 18 dB utilizing the gain control
select pin connected respectively to ground or V
also be adjusted externally by using an external resistor.
The SSM2304 is specified over the commercial temperature range
(−40°C to +85°C). It has built-in thermal shutdown and output
short-circuit protection. It is available in a 16-lead, 3 mm × 3 mm
lead-frame chip scale package (LFCSP).
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113 ©2006 Analog Devices, Inc. All rights reserved.
SSM2304
. Gain can
DD
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