Summary
The AK7845 is a mono audio power amplifier with a power booster designed to drive a piezo-electric speaker. The device employs AKM’s original Class-D amp architecture enabling stable audio output without the need of specific parts to drive such a capacitive load as a piezo-electronic speaker.
The built-in power booster based on DCDC converter technology produces a power rail of 13V from low supply voltage of down to 2.7V, allowing to provide high power in such as a low supply voltage application as Li-ion battery operation with very minimal external components.
AK7845 is available in a 24-pin WLCSP of 2.52.5mm body, and ideal for portable audio applications requiring serious saving of part space and power consumption.

Features

1. Stereo Class-D amplifier
   - Piezo-Electric (Ceramic) speaker or some capacitive load driver
   - 8Vrms BTL output with built-in power Booster
   - Filter-free for output stage
   - Supply current with no-input: 19.8mA
   - Shutdown current: 1A
   - Selectable Gain: 17dB to 29dB, 4dB step
   - Short-circuit and thermal protection
2. Boost DCDC converter
   - Boost voltage : 13.0V (Power supply: 2.7V to 4.5V)
   - Power Supply Rejection ratio : 50d
3. Input amplifier
   - Analogue signal input for differential or single-ended
   - Pop noise suppressor
4. Operational voltage and temperature
   - Power supply: 2.7V to 4.5V
   - Power supply for digital interface: 1.65V to 3.1V
   - Operational temperature: -30deg to +85deg
5. Package 24-pin WLCSP (2.5mm 2.5mm )