GENERAL DESCRIPTION

The AD8310 is a complete, dc to 440 MHz demodulating logarithmic amplifier (log amp) with a very fast voltage mode output, capable of driving up to 25 mA into a grounded load in under 15 ns. It uses the progressive compression (successive detection) technique to provide a dynamic range of up to 95 dB to ±3 dB law conformance or 90 dB to a ±1 dB error bound up to 100 MHz. It is extremely stable and easy to use, requiring no significant external components. A single-supply voltage of 2.7 V to 5.5 V at 8 mA is needed, corresponding to a power consumption of only 24 mW at 3 V. A fast-acting CMOS compatible enable pin is provided.

FEATURES

Multistage demodulating logarithmic amplifier

Voltage output, rise time <15 ns

High current capacity: 25 mA into grounded RL

95 dB dynamic range: −91 dBV to +4 dBV

Single supply of 2.7 V min at 8 mA typ

DC to 440 MHz operation, ±0.4 dB linearity

Slope of +24 mV/dB, intercept of −108 dBV

Highly stable scaling over temperature

Fully differential dc-coupled signal path

100 ns power-up time, 1 mA sleep current

APPLICATIONS

Conversion of signal level to decibel form

Transmitter antenna power measurement

Receiver signal strength indication (RSSI)

Low cost radar and sonar signal processing

Network and spectrum analyzers

Signal-level determination down to 20 Hz

True-decibel ac mode for multimeters