SSM2311 Datasheet, PDF (1/20 Pages) Analog Devices – Filterless High Efficiency Mono 3 W Class-D Audio Amplifier

Filterless High Efficiency
Mono 3 W Class-D Audio Amplifier
SSM2311
FEATURES
Filterless Class-D amplifier with Σ-Δ modulation
No sync necessary when using multiple Analog Devices, Inc.,
Class-D amplifiers
3 W into 3 Ω load and 1.4 W into 8 Ω load at 5.0 V supply with
less than 10% total harmonic distortion (THD)
90% efficiency at 5.0 V, 1.4 W into 8 Ω speaker
Better than 98 dB signal-to-noise ratio (SNR)
Single-supply operation from 2.5 V to 5.5 V
20 nA ultralow shutdown current
Short-circuit and thermal protection
Available in 9-ball, 1.5 mm × 1.5 mm WLCSP
Pop-and-click suppression
Built-in resistors reduce board component count
Default fixed 18 dB or user-adjustable gain setting
APPLICATIONS
Mobile phones
MP3 players
Portable gaming
Portable electronics
Educational toys
GENERAL DESCRIPTION
The SSM2311 is a fully integrated, high efficiency, Class-D audio
amplifier. It is designed to maximize performance for mobile
phone applications. The 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 a 3 Ω load from a 5.0 V supply.
The SSM2311 features a high efficiency, low noise modulation
scheme that does not require any external LC output filters. The
modulation continues to provide high efficiency even at low output
power. It operates with 90% efficiency at 1.4 W into 8 Ω or 85%
efficiency at 3 W into 3 Ω from a 5.0 V supply and has an SNR that
is better than 98 dB. Spread-spectrum pulse density modulation
is used to provide lower EMI-radiated emissions compared with
other Class-D architectures.
The SSM2311 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 device also includes pop-and-click suppression circuitry. 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 SSM2311 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 default gain of SSM2311 is 18 dB, but users can reduce the gain
by using a pair of external resistors (see the Gain section).
The SSM2311 is specified over the industrial temperature range
(−40°C to +85°C). It has built-in thermal shutdown and output
short-circuit protection. It is available in a 9-ball, 1.5 mm × 1.5 mm
wafer level chip scale package (WLCSP).
22nF¹ _REXT
AUDIO IN+
AUDIO IN–
22nF^{1 R}EXT
SHUTDOWN
FUNCTIONAL BLOCK DIAGRAM
10µF
SSM2311 ^300kΩ
0.1µF
VDD
VBATT
2.5V TO 5.0V
IN+ ^37.5kΩ
IN–
37.5kΩ
MODULATOR
FET
DRIVER
OUT+
OUT–
300kΩ
SD
BIAS
OSCILLATOR
POP-AND-CLICK
SUPPRESSION
300kΩ
GAIN
=
(37.5kΩ
+
R_EXT)
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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