Overview
The AD640JN is a complete monolithic logarithmic amplifier produced by Analog Devices Inc. This device provides up to 50 dB of dynamic range for frequencies from DC to 120 MHz, making it highly versatile for various applications. The AD640JN is part of the AD640 family, which includes models specified for different temperature ranges, such as the AD640J for commercial temperatures (0°C to +70°C), AD640B for industrial temperatures (–40°C to +85°C), and AD640T for military temperatures (–55°C to +125°C).
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| Transfer Function | IOUT = IY LOG |VIN/VX| for VIN = ± 0.75 mV to ± 200 mV dc | - | - | - | - |
| Input Resistance (Differential) | - | 500 | 500 | 500 | kΩ |
| Input Offset Voltage (Differential) | - | 50 | 200 | 200 | µV |
| Input Bias Current | - | 7 | 25 | 25 | µA |
| Common-Mode Range | - | -2 | - | +0.3 | V |
| Input Attenuator (Pin 5 to Pin 19) | - | 20 | 20 | 20 | dB |
| Logarithmic Output Slope (Current, IY) at f < 1 MHz | - | 0.96 | 1.0 | 1.04 | mA |
| 3 dB Bandwidth Each Stage | - | 350 | 350 | 350 | MHz |
Key Features
- Complete Monolithic System: The AD640JN is a fully integrated logarithmic amplifier, providing a complete solution in a single package.
- High Dynamic Range: Offers up to 50 dB of dynamic range for frequencies from DC to 120 MHz.
- Dual Polarity Current Outputs: Scaled 1 mA/Decade with voltage slope options such as 1 V/Decade, 100 mV/dB, etc..
- Low Power Operation: Typically operates at 220 mW at ±5 V.
- Stable Over Temperature Range: Logarithmic slope, intercept, and AC response are stable over the full military temperature range.
- Integral X10 Attenuator: Provides an alternative input range of ±7.5 mV to ±2 V DC.
Applications
- Radar, Sonar, and Ultrasonic Systems: Ideal for signal processing in these applications due to its high dynamic range and frequency response.
- Precision Instrumentation: Suitable for precision instrumentation from DC to 120 MHz.
- Power Measurement: Used for power measurement with absolute calibration.
- Audio Systems: Applicable in audio systems requiring logarithmic amplification.
- Signal Compression: Acts as a high accuracy signal compression alternative to discrete and hybrid IF strips.
Q & A
- What is the dynamic range of the AD640JN?
The AD640JN provides up to 50 dB of dynamic range for frequencies from DC to 120 MHz.
- What are the temperature ranges for the AD640JN?
The AD640JN is specified for the commercial temperature range of 0°C to +70°C. Other models in the AD640 family are specified for industrial and military temperature ranges.
- What is the input resistance of the AD640JN?
The input resistance is 500 kΩ (differential).
- Does the AD640JN have an integral attenuator?
Yes, it has an integral X10 attenuator that provides an alternative input range of ±7.5 mV to ±2 V DC.
- What is the typical power consumption of the AD640JN?
The AD640JN typically operates at 220 mW at ±5 V.
- What are the common applications of the AD640JN?
It is used in radar, sonar, ultrasonic systems, precision instrumentation, power measurement, and audio systems.
- What is the 3 dB bandwidth of each stage in the AD640JN?
Each stage has a 3 dB bandwidth of 350 MHz.
- Is the AD640JN available in different package types?
Yes, it is available in 20-lead plastic DIP (N) and PLCC (P) packages.
- What is the logarithmic output slope of the AD640JN?
The logarithmic output slope is scaled at 1 mA/Decade with options such as 1 V/Decade, 100 mV/dB, etc..
- Is the AD640JN stable over its operating temperature range?
Yes, the logarithmic slope, intercept, and AC response are stable over the full military temperature range.
