FT2850 G类单通道功放

GENERAL DESCRIPtiON
The ft2850 is a 5W Dual-PumpTM Class-AB/D/G audio
power amplifier with automatic level control (ALC) for
portable audio applications. It integrates Class-AB and
Class-D audio power amplifiers with a Class-G charge
pump regulator based upon proprietary Dual-PumpTM
topology. It operates from 3.3V to 5.3V supply. With a
supply voltage at 4.2V, it can deliver an output power of
5.4W with 10% THD+N, or 4.5W with 1% THD+N, into
a 4Ω speaker load.
In ft2850, the power supply rail of the audio amplifier’s
output stage is adaptively boosted and regulated by a
Class-G charge pump regulator, allowing much higher
audio loudness than a stand-alone one directly
connected to the battery. The adaptive nature of the
Class-G charge pump regulator, whose output voltage
varies dynamically in response to the level of the audio
output, improves overall power efficiency and extends
battery life when playing music. The higher output
power and greater power efficiency resulted from the
Class-G charge pump regulator make ft2850 an ideal
audio solution for battery-powered electronic devices.
To facilitate various applications, the ft2850 provides
three types of audio amplifier outputs, i.e., Class-AB,
Class-D, and Class-G. For typical applications, the
Class-G/D audio output is preferred for its high
efficiency. The Class-AB audio output can be chosen to
alleviate design complexities for applications where
minimum FM radio interference is required.
The ft2850 features ALC that constantly monitors and
safeguards the audio output against the boosted supply
voltage, preventing output clipping distortion, excessive
power dissipation, or speaker over-load. Once an
over-level condition is detected, the ALC lowers the
voltage gain of the audio amplifier proportionally to limit
the peak audio output voltage.
FEATURES
 Wide range of supply voltages from 3.3V to 5.3V
 Proprietary Dual-PumpTM topology
 Selectable types of audio outputs: Class-AB/D/G
 Filterless Class-D audio amplifier integrated with a
Class-G charge pump regulator
 Automatic level control to eliminate output clipping
 Selectable ALC dynamic characteristics
 Maximum output power (Non-ALC Mode)
6.2W (VDD=4.2V, THD+N=10%, RL=3Ω+33µH)
5.4W (VDD=4.2V, THD+N=10%, RL=4Ω+33µH)
3.2W (VDD=4.2V, THD+N=10%, RL=8Ω+33µH)
 ALC output power (ALC Mode)
5.0W (VDD=4.2V, THD+N=0.6%, RL=3Ω+33µH)
4.3W (VDD=4.2V, THD+N=0.6%, RL=4Ω+33µH)
2.4W (VDD=4.2V, THD+N=0.6%, RL=8Ω+33µH)
 Maximum Voltage Gain: 28dB
 ALC dynamic range: 9dB
 Low quiescent current: 4.5mA @ VDD=3.7V
 Low THD+N: 0.04%
(VDD=3.7V, f=1kHz, RL=4Ω+33µH, Po=0.5W)
 High PSRR: 68dB at 1kHz
 Selectable fade-in time
 Auto-recovering over-current and thermal-overload
protection
 Available in TSSOP-20L & QFN4X4-20L packages
APPLICATIONS
 Blue Tooth Speakers
 Smart Speakers
 Portable Consumer Electronic Devices
TYPICAL APPLICATION CIRCUIT