The AD745 is an ultralow noise, high-speed, FET input operational amplifier. It offers both the ultralow voltage noise and high speed generally associated with bipolar input op amps and the very low input currents of FET input devices. It is ideal for applications such as sonar, photodiode and IR detector amplifiers, accelerometers, low noise preamplifiers, and high-performance audio.
The AD745 op‑amp combines the low voltage‑noise of bipolar devices with the low input‑current of JFET inputs. It offers 2.9 nV/√Hz noise at 10 kHz, a 0.5 mV maximum offset voltage, and a 20 MHz gain‑bandwidth product, making it suitable for high‑speed, low‑noise applications such as sonar, photodiode amplifiers, and accelerometers.
The device is supplied in a 16‑lead SOIC package (AD745J/AD745K) for the commercial temperature range 0 °C to 70 °C. Electrical characteristics, absolute maximum ratings, ordering information, and typical performance graphs are provided, along with design considerations for low‑noise charge amplifiers and I‑to‑V converters.
| Noise voltage (10 kHz) | 2.9 nV/√Hz |
|---|---|
| Slew Rate | 12.5 V/µs |
| Gain‑Bandwidth Product | 20 MHz |
| Maximum Input Offset Voltage | 0.5 mV |
| Rated Power Supply | +15 V |
The AD745 achieves a noise density of 2.9 nV/√Hz at 10 kHz.
The op‑amp has a slew rate of 12.5 V/µs.
The gain‑bandwidth product is 20 MHz.
The AD745J and AD745K are rated for 0 °C to 70 °C.