PRODUCT DESCRIPTION

The AD641 is a 250 MHz, demodulating logarithmic amplifier with an accuracy of ±2.0 dB and 44 dB dynamic range. The AD641 uses a successive detection architecture to provide an output current that is logarithmically proportional to its input voltage. The output current can be converted to a voltage using one of several on-chip resistors to select the slope. A single AD641 provides up to 44 dB of dynamic range at speeds up to 250 MHz, and two cascaded AD641s together can provide 58 dB of dynamic range at speeds up to 250 MHz. The AD641 is fully stable and well characterized over either the industrial or military temperature ranges.

FEATURES

Logarithmic Amplifier Performance

Usable to 250 MHz

44 dB Dynamic Range

±2.0 dB Log Conformance

37.5 mV/√dB Voltage Output

Stable Slope and Intercepts

2.0 nV/√Hz Input Noise Voltage

50 μV Input Offset Voltage

Low Power

±5 V Supply Operation

9 mA (+VS), 35 mA (–VS) Quiescent Current

Onboard Resistors

Onboard 10x Attenuator

Dual Polarity Current Outputs

Direct Coupled Differential Signal Path

APPLICATIONS

IF/RF Signal Processing

Received Signal Strength Indicator (RSSI)

High Speed Signal Compression

High Speed Spectrum Analyzer

ECM/Radar