Summary
The AK7837A is an audio amplifier for dynamic speakers to be used in both louder and receiver on mobile phones, which can share one speaker. AK7837A has input pins for each mode and output pins for one speaker.
AK7837A uses class-AB amplifier to achieve high quality sound for receiver mode and class-D method for sounder mode to suppress consumption power.
Built-in ALC (Auto Level Controller) circuit and Voltage Monitor circuit will prevent excessive output into the speaker. The ALC also helps to increase sound volume until specified level in sounder mode. AK7837A has double guards from unexpected huge sound, and effect to eliminate receiver speaker.
AK7837A is available in a small 16-pin WL-CSP package.

Features

1. Two-way audio amplifier
   -Two input for Receiver and Louder, One output to 8ohm Dynamic speaker4), 15dB(AK7835S5, AK7835B5)
2. Louder Mode
   - Low power consumption Class-D amplifier
   - 1.2W into 8ohm load (THD+N=10%, VDD=5V)
   - Filter-free for output stage
   - Low EMI noise
   - Selectable gain: 0dB to +31.5dB
   - ALC Limiter function to protect speaker
   - Fast recovery to keep comfortable sound quality
   - Short-circuit and thermal protection
3. Receiver Mode
   - High Quality Class-AB amplifier
   - 0.4mW into 8ohm load
   - Selectable gain: -27dB to +4.5dB
   - ALC function to limit sound level
   - Voltage Monitor function to watch the signal level outputted to speaker
   - LPF tunable to cut-off frequency
4. Input Amplifier
   - Analogue signal input by single-ended for Louder
   - Analogue signal input by differential or single-ended for Receiver
   - Pop noise suppressor
5. Control resisters
   - Accessible by I²C interface
   - Switch Receiver mode or Louder mode
   - Tuning gain, ALC parameters
6. Operational voltage and temperature
   - Power supply: 2.5V to 5.0V
   - Power supply for digital interface: 1.65V to 5.0V
   - Operational temperature: -30deg to +85deg
7. Package WL-CSP 16-pin (2.16mm 2.21mm)