LOG104

Features:

· EASY-TO-USE COMPLETE CORE FUNCTION
· HIGH ACCURACY: 0.01% FSO Over 5 Decades
· WIDE INPUT DYNAMIC RANGE: 7.5 Decades, 100pA to 3.5mA
· LOW QUIESCENT CURRENT: 1mA
· WIDE SUPPLY RANGE: ±4.5V to ±18V


Application

· LOG, LOG RATIO COMPUTATION: Communication, Analytical, Medical, Industrial, Test, General Instrumentation
· PHOTODIODE SIGNAL COMPRESSION AMP
· ANALOG SIGNAL COMPRESSION IN FRONT OF ANALOG-TO-DIGITAL(A/D) CONVERTER


Pinout




Specifications

Supply Voltage, V+ to V .................................... 36V Input Voltage .......................... V (0.5) to V+ (+0.5V) Input Current ............................................ .........±10mA Output Short-Circuit(2) ................................. Continuous Operating Temperature ...........................40 to +85 Storage Temperature .............................55 to +125 Junction Temperature .......................................... +150 Lead Temperature (soldering, 10s) .......................+300 NOTES: (1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. (2) Short-circuit to ground.


Description

The LOG104 is a versatile integrated circuit that computes the logarithm or log ratio of an input current relative to a reference current.

The LOG104 is tested over a wide dynamic range of input signals. In log ratio applications, a signal current can come from a photodiode, and a reference current from a resistor in series with a precision external reference.

The output signal at VOUT is trimmed to 0.5V per decade of input current, allowing seven decades of input current, dynamic range.

Low DC offset voltage and temperature drift allow accurate measurement of low-level signals over a wide environmental temperature range. The LOG104 is specified over the temperature range 5  to +75 , with operation over 40  to +85 .