Filterless, High Efficiency,
Mono 3 W Class-D Audio Amplifier
SSM2319
The SSM2319 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
of 98 dB. Spread-spectrum pulse density modulation is used to
provide lower EMI-radiated emissions compared with other
Class-D architectures.
FEATURES
Filterless Class-D amplifier with ultraefficient spread-
spectrum Σ-Δ modulation
Internal modulator synchronization (SYNC)
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)
90% efficiency at 5.0 V, 1.4 W into 8 Ω speaker
Signal-to-noise ratio (SNR): 98 dB
Single-supply operation: 2.5 V to 5.5 V
Ultralow shutdown current: 20 nA
SYNC can be activated in the event that end users are concerned
about clock intermodulation (beating effect) of several amplifiers in
close proximity.
Short-circuit and thermal protection with autorecovery
Available in 9-ball, 1.5 mm × 1.5 mm WLCSP
Pop-and-click suppression
Built-in resistors reduce board component count
Default fixed 12 dB or user-adjustable gain setting
The SSM2319 has a micropower shutdown mode with a typical
shutdown current of 20 nA. Shutdown is enabled by applying a
SD
logic low to the
pin.
APPLICATIONS
The device also includes pop-and-click suppression circuitry.
This minimizes voltage glitches at the output during turn-on and
turn-off, reducing audible noise on activation and deactivation.
Mobile phones
MP3 players
Portable gaming
Portable electronics
Educational toys
The default gain of the SSM2319 is 12 dB, but users can reduce
the gain by using a pair of external resistors (see the Gain section).
The SSM2319 is specified 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 9-ball, 1.5 mm × 1.5 mm
wafer level chip scale package (WLCSP).
GENERAL DESCRIPTION
The SSM2319 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 <1% THD + N driving a 3 Ω load from a
5.0 V supply.
FUNCTIONAL BLOCK DIAGRAM
0.1µF
10µF
VBATT
2.5V TO 5.5V
VDD
SSM2319
160kΩ
0.1µF*
0.1µF*
40kΩ
IN–
IN+
OUT+
OUT–
AUDIO IN–
AUDIO IN+
MODULATOR
FET
DRIVER
40kΩ
(Σ-Δ)
160kΩ
POP/CLICK
SUPPRESSION
SD
INTERNAL
OSCILLATOR
SHUTDOWN
BIAS
SYNC
SYNC OUTPUT
SYNCO
GND
SYNCI
SYNC INPUT
*INPUT CAPACITORS ARE OPTIONAL IF INPUT DC COMMON-MODE
VOLTAGE IS APPROXIMATELY V /2.
DD
Figure 1.
Rev. 0
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