The AD603 is a low noise, voltage-controlled amplifier for use in RF and IF AGC systems. It provides accurate, pin-selectable gains of −11 dB to +31 dB with a bandwidth of 90 MHz or +9 dB to 51+ dB with a bandwidth of 9 MHz. Any intermediate gain range may be arranged using one external resistor. The input referred noise spectral density is only 1.3 nV/√Hz, gain accuracy typical is ±0.5 dB. The AD603 is constructed using bipolar input transistors, providing low input bias current for high precision gain control. It also has a low supply voltage and low power consumption, making it an ideal choice for RF and IF AGC applications.
The AD603 is a low‑noise, variable‑gain amplifier designed for RF/IF applications such as AGC, video gain control, and signal measurement. It offers linear‑in‑dB gain control, pin‑programmable gain ranges, and a bandwidth that remains independent of the selected gain.
The datasheet provides detailed specifications, pin configurations, typical performance graphs, and information on the gain‑control interface, absolute maximum ratings, and recommended operating conditions.
| Input Resistance (Pin 3‑Pin 4) | 97 Ω – 103 Ω |
|---|---|
| Input Noise Spectral Density | 13 nV/√Hz |
| 3‑dB Bandwidth | 90 MHz |
| Supply Voltage (Absolute Maximum) | +7.5 V |
| Operating Supply Range | +4.75 V – +6.3 V |
| Quiescent Current | 12.5 mA – 17 mA |
| Gain Scaling Factor (100 kHz) | 40 dB/V |
| Input Bias Current | 200 nA |
| Output Impedance (f < 10 MHz) | 2 Ω |
The AD603 has an input noise spectral density of 13 nV/√Hz when the input is short‑circuited.
The gain‑control inputs (GNEG, GPOS) accept voltages from –1.2 V to +2.0 V.
The absolute maximum supply voltage is +7.5 V.
The device draws between 12.5 mA and 17 mA of quiescent current.