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.