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

APPLICATIONS
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

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°C to +75°C, with operation over –40°C to
+85°C.