The MAX9812/MAX9813 are single/dual-input, 20dB fixed-gain microphone amplifiers. They offer tiny pack- aging and a low-noise, integrated microphone bias, making them ideal for portable audio applications such as notebook computers, cell phones, and PDAs.
The MAX9812/MAX9813 are single‑ or dual‑input microphone amplifiers designed for portable audio applications such as notebook computers, cell phones, and PDAs. They feature a 20 dB fixed gain, 500 kHz bandwidth, rail‑to‑rail outputs, and an industry‑leading 100 dB power‑supply rejection ratio.
Both devices are offered in two voltage grades: the L version operates from 2.7 V to 3.6 V, while the H version is PC2001‑compliant and operates from 4.5 V to 5.5 V. They provide a low‑noise integrated microphone bias (2.3 V or 4.0 V) and include a shutdown mode that reduces supply current to 100 nA.
| Fixed Gain | 20 dB |
|---|---|
| Bandwidth | 500 kHz |
| Power‑Supply Rejection Ratio | 100 dB at 217 Hz |
| Total Harmonic Distortion + Noise | 0.015 % |
| Input Impedance | 85 kΩ |
| Output Swing | within 100 mV of the rails |
| Operating Temperature Range | -40 °C to +85 °C |
Both devices have a fixed gain of 20 dB.
The input impedance is typically 85 kΩ.