LOG2112

Features:

· EASY-TO-USE COMPLETE FUNCTION
· OUTPUT SCALING AMPLIFIER
· ON-CHIP 2.5V VOLTAGE REFERENCE
· HIGH ACCURACY: 0.2% FSO Over 5 Decades
· WIDE INPUT DYNAMIC RANGE: 7.5 Decades, 100pA to 3.5mA
· LOW QUIESCENT CURRENT: 1.75mA
· WIDE SUPPLY RANGE: ±4.5V to ±18V
· PACKAGES: SO-14 (narrow) and SO-16


Application

· LOG, LOG RATIO: Communication, Analytical, Medical, Industrial, Test, General Instrumentation
· PHOTODIODE SIGNAL COMPRESSION AMP
· ANALOG SIGNAL COMPRESSION IN FRON T OF ANALOG-TO-DIGITAL (A/D) CONVERTER
· ABSORBANCE MEASUREMENT
· OPTICAL DENSITY MEASUREMENT


Specifications

Supply Voltage, V+ to V ........................................ ±18V Input Voltage ........................................................... ±18V Input Current ......................................................... ±10mA Output Short-Circuit(2) ..................................... Continuous Operating Temperature ..........................40°C to +85°C Storage Temperature ...........................55°C to +125°C Junction Temperature ................................... ........+150°C Lead Temperature (soldering, 10s) .......................+300°C


Description

`The LOG112 and LOG2112 are versatile integrated circuits that compute the logarithm or log ratio of an input current relative to a reference current. VLOGOUT of the LOG112 and LOG2112 are trimmed to 0.5V per decade of input current, ensuring high precision over a wide dynamic range of input signals.

`The LOG112 and LOG2112 features a 2.5V voltage reference that may be used to generate a precision current reference using an external resistor.

`Low DC offset voltage and temperature drift allow accurate measurement of low-level signals over the specified temperature range of 5  to +75 .