The AD8641/AD8642/AD8643 are low power, precision JFET input amplifiers featuring extremely low input bias current and rail-to-rail output. The ability to swing nearly rail-to-rail at the input and rail-to-rail at the output enables designers to buffer CMOS DACs, ASICs, and other wide output swing devices.
The AD8641, AD8642, and AD8643 are low‑power, precision JFET input amplifiers with extremely low input bias current and rail‑to‑rail output. They are designed for single‑supply (5 V to 26 V) or dual‑supply (+2.5 V to +13 V) operation and maintain stability with capacitive loads over 500 pF.
These devices are offered in multiple lead‑free packages (SC70, SOIC, MSOP, LFCSP) and are rated for an industrial temperature range of –40 °C to +125 °C. The datasheet includes detailed electrical characteristics, absolute maximum ratings, typical performance curves, and ordering information.
| Supply current (typical) | 250 pA max |
|---|---|
| Input bias current | 1 pA max |
| Offset voltage | 750 pV max |
| Single‑supply voltage range | 5 V to 26 V |
| Dual‑supply voltage range | +2.5 V to +13 V |
| Output high voltage (1 mA load) | 4.95 V |
| Slew rate | 2 V/µs |
| Gain‑bandwidth product (AD8641/AD8642) | 3 MHz |
| Gain‑bandwidth product (AD8643) | 25 MHz |
| Voltage noise (0.1‑10 Hz) | 4.0 µV p‑p |
| Phase margin | 50 degrees |
They operate from 5 V up to 26 V on a single supply, or from +2.5 V to +13 V on a dual supply.
The input bias current is as low as 1 pA (maximum).
The AD8643 is offered in a 14‑lead SOIC and a 16‑lead LFCSP (3 mm × 3 mm) lead‑free packages.