755P

Features:

Complete Log/Antilog Amplifier
-External Components Not Required;
-Internal Reference; Temperature Compensated
6 Decades Current Operation - 1nA to 1mA
-½% max Error - 10nA to 100mA
-1% max Error - 1nA to 1mA
4 Decades Voltage Operation - 1mV to 10V,
-½% max Error - 1mV to 1V
-1% max Error - 1mV to 10V


Application

Log Current or Voltage
Antilog Voltage
Data Compression or Expansion
Absorbence Measurements
Computing Powers and Log Ratios


Description

   Model 755P is a complete dc logarithmic amplifier consisting of an accurate temperature compensated antilog element, and a low bias current FET amplifier. In addition to offering 120dB of current logging (1nA to 1mA) and 80dB of voltage logging (1mV to 10V), the 755 features exceptionally low bias currents of 10pA and 15mV/°C voltage drift to satisfy most wide range applications. Conformance to ideal log operation is held to ±1% over its total 120dB current range (1nA to 1mA), with ±0.5% conformity guaranteed over an 80dB range (10nA to 100mA). Two models of the 755P are available, model 755N and model 755P. The N version computes the log of positive input signals and the P version computes the log of negative input signals.

   Advanced design techniques and improved component selection of the 755P are used to obtain exceptionally good performance. For example, the use of monolithic devices greatly reduces the influence of temperature variations. Offering both log and antilog operation, model 755's price and performance are especially attractive as an alternative to in-house designs of OEM applications. This log design also improves significantly over competitive designs in price, performance, and package size.