Power Amplifier. ft2820 Datasheet
4W Dual-PumpTM Class-G Audio Power Amplifier
The ft2820 is a 4W boosted Class-G audio power
amplifier based upon a proprietary Dual-PumpTM
topology with automatic level control (ALC). It
operates from 3V to 5.5V supply. When operating
with a 4.2V supply voltage, it is capable of driving a
4Ω speaker load at a continuous average output of
4W with 10% THD+N. Its high efficiency, up to 82%,
helps extend battery life for portable device
In ft2820, the power supply rail for the amplifier’s
output stage is internally boosted and regulated at
6V by an adaptive charge pump based upon the
Dual-PumpTM topology, thus allowing for a much
louder audio output than a stand-alone one directly
connected to the battery. It makes ft2820 an ideal
audio solution for portable devices that are powered
by a single-cell lithium battery while requiring higher
The ft2820 features ALC on the audio output signals,
which detects the output clipping caused by the
over-level input signal and automatically adjusts the
voltage gain of the amplifier to eliminate the clipping
while maintaining the maximally-allowed dynamic
range of the audio output signals. The ALC also
eliminates the output clipping due to low battery
Proprietary Dual-PumpTM topology
Filterless Class-G operation with an integrated
Automatic level control to eliminate output
Integrated lowpass filter for out-of-band noise
Maximum output power: 4W
(VDD=4.2V, RL=4Ω, THD+N=10%, ALC Off)
Constant output power: 3.3W
(VDD=4.2V, RL=4Ω, THD+N=0.5%, ALC On)
High power efficiency up to 82%
Low THD+N: 0.05%
(VDD=3.6V, f=1kHz, RL=4Ω, Po=1W)
ALC dynamic range: 10.5dB
Low quiescent current: 2.7mA @ VDD=3.6V
High PSRR: 75dB @ 217Hz
Two gain settings: 24.1/27.6dB
One-wire pulse control to set operating mode
and voltage gain
Auto-recovering short-circuit protection
Available in TSSOP-20L package
C F1 2.2uF C F2 2.2uF
CVDD CP1 CN1 CP2 CN2
Figure 1: Typical Application Circuit Diagram
PIN CONFIGURATION AND DESCRIPTION
ft2820P (TOP VIEW)
7, 11, 12
I Chip enable & one-wire pulse control.
O Flying capacitor CF2 negative terminal.
O Flying capacitor CF2 positive terminal.
P Power supply for the charge pump.
I Negative audio input terminal.
I Positive audio input terminal.
P Analog power supply.
Power supply rail for the Class-D amplifier output stage. It must be
externally shorted to PVOUT.
O Negative BTL audio output.
G Ground for the Class-D amplifier output stage.
O Positive BTL audio output.
O Flying capacitor CF1 positive terminal.
Boosted voltage output generated by the charge pump. It must be
externally shorted to PVDD on the system board.
O Flying capacitor CF1 negative terminal.
G Ground for the charge pump.
G Analog ground.
- No internal connection.
-40°C to +85°C