The MAX9945 is a low-power, low-noise, MOS-input operational amplifier with a wide power supply range, low quiescent current, and high output swing.
The MAX9945 operational amplifier combines low operating power (400 µA quiescent current) with ultra‑low input bias current (50 fA) and input current noise (1 fA/√Hz). It supports a single‑supply voltage range of 4.75 V to 38 V and delivers rail‑to‑rail output swing, making it suitable for portable medical and industrial sensor front‑ends.
The device is offered in 6‑pin TDFN and 8‑pin µMAX packages and is specified for automotive temperature ranges (‑40 °C to +125 °C). Detailed electrical characteristics, typical performance curves, and layout recommendations are provided for high‑impedance sensor applications such as photodiode trans‑impedance amplifiers and chemical sensor interfaces.
| Supply Voltage Range | 4.75 V to 38 V |
|---|---|
| Quiescent Supply Current | 400 µA |
| Input Bias Current | 50 fA (typ) |
| Input Current‑Noise Density | 1 fA/√Hz (typ) |
| Input Voltage‑Noise Density | 15 nV/√Hz (typ) |
| Unity‑Gain Bandwidth | 3 MHz |
| Slew Rate | 2.2 V/µs |
| Output Voltage Swing | Rail‑to‑Rail (±0.05 V typ) |
| Operating Temperature Range | ‑40 °C to +125 °C |
The MAX9945 operates from 4.75 V up to 38 V.
It draws a low 400 µA quiescent supply current.
The typical input bias current is 50 fA.
Yes, the device is unity‑gain stable.