Overview
The AD603AQ, 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 AD603AQ 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 temperature and supply variations.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Resistance | 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 | ||
| Power Consumption (VS = ±5 V) | 125 | mW | ||
| Operating Temperature Range | −40 | +85 | °C |
Key Features
- Linear-in-dB gain control with a scaling factor of 25 mV/dB.
- Pin-selectable gains from −11 dB to +31 dB with a bandwidth of 90 MHz or +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.
- Differential gain control interface supporting single-ended or differential control voltages.
- Ability to drive load impedances as low as 100 Ω with low distortion.
- Total harmonic distortion of −60 dBc for a ±1 V sinusoidal output at 10 MHz into a 500 Ω load.
- Peak specified output of ±2.5 V minimum into a 500 Ω load.
Applications
- RF/IF AGC amplifiers.
- Video gain controls.
- A/D range extensions.
- Signal measurements.
Q & A
- What is the gain range of the AD603AQ? The AD603AQ provides gains 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 AD603AQ? The input noise spectral density is 1.3 nV/√Hz.
- How is the gain controlled in the AD603AQ? The gain is controlled through a high impedance (50 MΩ) differential input with a scaling factor of 25 mV/dB.
- What is the power consumption of the AD603AQ? The power consumption is 125 mW at the recommended ±5 V supplies.
- What is the operating temperature range of the AD603AQ? The operating temperature range is from −40°C to +85°C.
- Can the AD603AQ drive low impedance loads? Yes, the AD603AQ can drive load impedances as low as 100 Ω with low distortion.
- What is the total harmonic distortion of the AD603AQ? The total harmonic distortion is typically −60 dBc for a ±1 V sinusoidal output at 10 MHz into a 500 Ω load.
- What is the peak specified output of the AD603AQ? The peak specified output is ±2.5 V minimum into a 500 Ω load.
- Can multiple AD603AQ amplifiers be cascaded? Yes, several AD603AQ amplifiers can be cascaded and their gain control gains offset to optimize the system SNR.
- What is the proprietary circuit topology used in the AD603AQ? The AD603AQ uses the patented X-AMP® topology, which includes a variable attenuator followed by a fixed-gain amplifier.
