Datasheet Analog Devices AD8310ACHIPS
Fast, VoltageOut, DC to 440 MHz, 95 dB Logarithmic Amplifier Datasheets Download » Datasheet, PDF, 396 Kb
Docket ↓Fast, VoltageOut, DC to 440 MHz, 95 dB Logarithmic Amplifier AD8310 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 dccoupled signal path 100 ns powerup time, 1 mA sleep current SUPPLY 5 FUNCTIONAL BLOCK DIAGRAM VPOS 8mA BAND GAP REFERENCE AND BIASING INHI 1.0k INLO 3 NINE DETECTOR CELLS SPACED 14.3dB COMMON 2 AD8310 ENBL BFIN 7 ENABLE BUFFER INPUT SIX 14.3dB 900MHz AMPLIFIER STAGES MIRROR 2A /dB 2 3k COMM 6 +INPUT INPUT 8 1 + VOUT 3k 4 OUTPUT COMM INPUTOFFSET COMPENSATION LOOP 1k OFLT 33pF COMM 3 COMM 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 Signallevel determination down to 20 Hz Truedecibel ac mode for multimeters Figure 1. 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 singlesupply 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 fastacting CMOScompatible enable pin is provided. Each of the six cascaded amplifier/limiter cells has a smallsignal gain of 14.3 dB, with a 3 dB bandwidth of 900 MHz. A total of nine detector cells are used to provide a dynamic range that extends from 91 dBV (where 0 dBV is defined as the amplitude of a 1 V rms sine wave), an amplitude of about ±40 V, up to +4 dBV (or ±2.2 V). The demodulated output is accurately scaled, with a log slope of 24 mV/dB and an intercept of 108 dBV. The scaling parameters are supplyand temperatureindependent. The fully differential input offers a moderately high impedance (1 k in parallel with about 1 pF). A simple network can match the input to 50 and provide a power sensitivity of 78 dBm to +17 dBm. The logarithmic linearity is typically within ±0.4 dB up to 100 MHz over the central portion of the range, but it is somewhat grea ...
Docket: Fast, VoltageOut, DC to 440 MHz, 95 dB Logarithmic Amplifier AD8310 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 dccoupled signal path 100 ns powerup time, 1 mA sleep current SUPPLY 5 FUNCTIONAL BLOCK DIAGRAM VPOS 8mA BAND GAP REFERENCE AND BIASING INHI 1.0k INLO 3 NINE DETECTOR CELLS SPACED 14.3dB COMMON 2 AD8310 ENBL BFIN 7 ENABLE BUFFER INPUT SIX 14.3dB 900MHz AMPLIFIER STAGES MIRROR 2A /dB 2 3k COMM 6 +INPUT INPUT 8 1 + VOUT 3k 4 OUTPUT COMM INPUTOFFSET COMPENSATION LOOP 1k OFLT 33pF COMM 3 COMM 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 Signallevel determination down to 20 Hz Truedecibel ac mode for multimeters Figure 1. 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 u...

