AD549 Ultra Low Input Bias Current Operational Amplifier
The AD549 is a monolithic electrometer operational amplifier with very low input bias current. Input offset voltage and input offset voltage drift are lasers trimmed for precision performance. The ultralow input current of the part is achieved with Topgate™ JFET technology, a process development exclusive to Analog Devices, Inc. This technology allows the fabrication of extremely low input current JFETs compatible with a standard junction isolated bipolar process. The 1015 Ω common-mode impedance, which results from the bootstrapped input stage, ensures that the input current is essentially independent of the common-mode voltage. The AD549 is suited for applications requiring very low input current and low input offset voltage. It excels as a preamp for a wide variety of current output transducers, such as photodiodes, photomultiplier tubes, or oxygen sensors. The AD549 can also be used as a precision integrator or low droop sample-and-hold. The AD549 is pin-compatible with standard FET and electrometer op-amps, allowing designers to upgrade the performance of present systems at little additional cost.
- Electrometer amplifier
- Photodiode preamp
- pH electrode buffer
- Input bias current guaranteed over the common-mode
Low offset voltage
- 0.50 mV maximum
- Low offset drift
- 15 μV/°C maximum
- Low power
- 700 μA maximum supply current
- Low input voltage noise
- 4 μV (typ) p-p over 0.1 Hz to 10 Hz
- MIL-STD-883B parts available
Note: Product Images are shown for illustrative purposes only and may differ from actual product.