Overview
The AD603AR, produced by Analog Devices Inc., is a low noise, voltage-controlled amplifier designed for use in RF and IF AGC (Automatic Gain Control) systems. This amplifier provides accurate, pin-selectable gains ranging from −11 dB to +31 dB with a bandwidth of 90 MHz, or from +9 dB to +51 dB with a bandwidth of 9 MHz. The AD603AR features a patented proprietary circuit topology known as the X-AMP®, which includes a variable attenuator followed by a fixed-gain amplifier. This design ensures stable and linear gain control over a wide range of temperatures and supply voltages.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Resistance (Pin 3 to Pin 4) | 97 | 100 | 103 | Ω |
| Input Capacitance | 2 | pF | ||
| Input Noise Spectral Density | 1.3 | nV/√Hz | ||
| Noise Figure (f = 10 MHz, gain = maximum, RS = 10 Ω) | 8.8 | dB | ||
| 1 dB Compression Point (f = 10 MHz, gain = maximum, RS = 10 Ω) | −11 | dBm | ||
| Peak Input Voltage | ±1.4 | ±2 | V | |
| -3 dB Bandwidth (VOUT = 100 mV rms) | 90 | MHz | ||
| Supply Voltage | ±4.75 | ±6.3 | V | |
| Supply Current | 12.5 | mA | ||
| Operating Temperature | −40 | +85 | °C |
Key Features
- Linear-in-dB gain control with pin-selectable gains from −11 dB to +31 dB and bandwidth of 90 MHz, or from +9 dB to +51 dB with a bandwidth of 9 MHz.
- Low input noise spectral density of 1.3 nV/√Hz.
- High impedance (50 MΩ) and low bias (200 nA) differential input.
- Gain control scaling factor of 25 mV/dB, requiring only 1 V to span the central 40 dB of the gain range.
- Fast gain control response time of less than 1 μs for a 40 dB change.
- Ability to drive a load impedance as low as 100 Ω with low distortion.
- Total harmonic distortion of typically −60 dBc for a ±1 V sinusoidal output at 10 MHz into a 500 Ω load with 5 pF shunt capacitance.
- Peak specified output of ±2.5 V minimum into a 500 Ω load.
- Proprietary X-AMP® circuit topology with a variable attenuator followed by a fixed-gain amplifier.
Applications
- RF/IF AGC (Automatic Gain Control) amplifiers.
- Video gain controls.
- A/D range extensions.
- Signal measurements.
Q & A
- What is the gain range of the AD603AR?
The AD603AR provides gains ranging from −11 dB to +31 dB with a bandwidth of 90 MHz, or from +9 dB to +51 dB with a bandwidth of 9 MHz.
- What is the input noise spectral density of the AD603AR?
The input noise spectral density is 1.3 nV/√Hz.
- What is the supply voltage range for the AD603AR?
The supply voltage range is ±4.75 V to ±6.3 V.
- What is the operating temperature range of the AD603AR?
The operating temperature range is from −40°C to +85°C.
- How fast is the gain control response time of the AD603AR?
The gain control response time is less than 1 μs for a 40 dB change.
- What is the typical total harmonic distortion for the AD603AR?
The typical total harmonic distortion is −60 dBc for a ±1 V sinusoidal output at 10 MHz into a 500 Ω load with 5 pF shunt capacitance.
- What is the peak specified output voltage of the AD603AR?
The peak specified output voltage is ±2.5 V minimum into a 500 Ω load.
- What is the X-AMP® circuit topology used in the AD603AR?
The X-AMP® circuit topology includes a variable attenuator followed by a fixed-gain amplifier.
- Can the AD603AR be cascaded to optimize system SNR?
Yes, several AD603AR amplifiers can be cascaded and their gain control gains offset to optimize the system SNR.
- What are some common applications of the AD603AR?
Common applications include RF/IF AGC amplifiers, video gain controls, A/D range extensions, and signal measurements.
