Overview
The AD603SQ/883B, 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 AD603 features a patented X-AMP® topology, which includes a variable attenuator followed by a fixed-gain amplifier, ensuring high performance and stability over temperature and supply variations. The device is known for its low input noise spectral density of 1.3 nV/√Hz and its ability to drive low impedance loads with minimal distortion.
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 (Max) | 6.3 | V | ||
| Operating Temperature | -55 | 125 | °C | |
| Power Consumption (VS = ±5 V) | 125 | mW |
Key Features
- Low noise spectral density of 1.3 nV/√Hz.
- Accurate, pin-selectable 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.
- High impedance (50 MΩ), low bias (200 nA) differential input for gain control.
- Differential gain control interface supporting either differential or single-ended positive or negative control voltages.
- Ability to drive load impedances 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 in shunt with 5 pF.
- Peak specified output of ±2.5 V minimum into a 500 Ω load.
- Patented X-AMP® topology with a variable attenuator and a fixed-gain amplifier.
- Fast gain control response time of less than 1 μs for a 40 dB change.
Applications
- RF/IF AGC amplifiers.
- Video gain controls.
- A/D range extensions.
- Signal measurements.
Q & A
- What is the input noise spectral density of the AD603SQ/883B?
The input noise spectral density is 1.3 nV/√Hz.
- What are the gain ranges available for the AD603SQ/883B?
The AD603 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 maximum supply voltage for the AD603SQ/883B?
The maximum supply voltage is 6.3 V.
- What is the operating temperature range for the AD603SQ/883B?
The operating temperature range is from −55°C to 125°C.
- How does the gain control interface work?
The gain control interface is differential and can use either differential or single-ended positive or negative control voltages.
- What is the total harmonic distortion for a ±1 V sinusoidal output at 10 MHz?
The total harmonic distortion is typically −60 dBc for a ±1 V sinusoidal output at 10 MHz into a 500 Ω load in shunt with 5 pF.
- Can the AD603SQ/883B drive low impedance loads?
Yes, the AD603 can drive load impedances as low as 100 Ω with low distortion.
- What is the peak specified output voltage into a 500 Ω load?
The peak specified output voltage is ±2.5 V minimum into a 500 Ω load.
- How fast is the gain control response time?
The gain control response time is less than 1 μs for a 40 dB change.
- What is the X-AMP® topology used in the AD603SQ/883B?
The X-AMP® topology includes a variable attenuator followed by a fixed-gain amplifier, ensuring high performance and stability.
