SSM2306 Datasheet, PDF (1/16 Pages) Analog Devices – 2 W, Filterless, Class-D Stereo Audio Amplifier

2 W, Filterless, Class-D
Stereo Audio Amplifier
SSM2306
FEATURES
Filterless Class-D amplifier with built-in output stage
2 W into 4 Ω and 1.4 W into 8 Ω at 5.0 V supply
Ultralow idle current with load resistance
>87% efficiency at 5.0 V, 1.4 W into 8 Ω speaker
Better than 96 dB SNR (signal-to-noise ratio)
Available in 16-lead, 3 mm × 3 mm LFCSP
Single-supply operation from 2.5 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 18 dB gain and user-adjustable
APPLICATIONS
Mobile phones
MP3 players
Portable gaming
Portable electronics
Educational toys
Notebook computers
GENERAL DESCRIPTION
The SSM2306 is a fully integrated, high efficiency, Class-D stereo
audio amplifier designed to maximize performance for portable
applications. The application circuit requires minimum external
components and operates from a single 2.5 V to 5.0 V supply. It
is capable of delivering 2 W of continuous output power with less
than 10% THD + N driving a 4 Ω load from a 5.0 V supply.
The SSM2306 features ultralow idle current, high efficiency, and
a low noise modulation scheme. It operates with >87% efficiency
at 1.4 W into 8 Ω from a 5.0 V supply and has a signal-to-noise
ratio (SNR) that is better than 96 dB. PDM modulation offers lower
EMI radiated emissions compared to other Class-D architectures.
The SSM2306 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 to minimize voltage glitches at the output
during turn-on and turn-off, thereby reducing audible noise on
activation and deactivation. The fully differential input of the
SSM2306 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 VDD/2.
The SSM2306 also has excellent rejection of power supply noise,
including noise caused by GSM transmission bursts and RF
rectification.
The SSM2306 has a preset gain of 18 dB that can be reduced by
using external resistors.
The SSM2306 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).
FUNCTIONAL BLOCK DIAGRAM
10µF
22nF¹
RIGHT IN+
RIGHT IN–
22nF¹
R_EXT
R_EXT
SHUTDOWN
22nF¹ _REXT
LEFT IN+
LEFT IN–
22nF^{1 R}EXT
GAIN = 344kΩ/(43kΩ + R_EXT)
SSM2306 344kΩ
43kΩ
INR+
INR– _43kΩ
344kΩ
BIAS
SD
344kΩ
INL+
INL–
43kΩ
43kΩ
344kΩ
0.1µF
VDD
MODULATOR
VBATT
2.5V TO 5.0V
VDD
FET
DRIVER
OUTR+
OUTR–
INTERNAL
OSCILLATOR
MODULATOR
GND
FET
DRIVER
OUTL+
OUTL–
GND
1 _{INPUT CAPS ARE OPTIONAL IF INPUT DC COMMON-MODE}
VOLTAGE IS APPROXIMATELY V_DD/2.
Figure 1.
Rev. 0
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