4127KG

Overview

The Texas Instruments 4127KG is a hybrid logarithmic amplifier housed in a 24-pin ceramic double wide DIP package. It accepts input currents or voltages of either polarity, supporting six decades of current and four decades of voltage. The device features an internal current inverter, precise reference, and an uncommitted operational amplifier for versatile log, antilog, and log ratio configurations. Rated supplies are ±15VDC with a range of ±14V to ±16V. Operating temperature spans –10 °C to +70 °C. Accuracy is 0.5% max for the KG model.

Feature Summary

• Accepts input signals of either polarity from current or voltage sources
• Pin-programmable for logarithmic, log ratio, or antilog functions
• Includes an uncommitted operational amplifier for buffering or filtering

Applications

• Signal compression
• Transducer linearization
• Phototube buffering

Procurement Notes

Verify component status as NRND (Not Recommended for New Designs). Confirm package type matches CDIP JNA 24-pin specifications. Review datasheet for adjustment procedures regarding scale factor and reference current trimming. Ensure supply voltage requirements align with ±15VDC rated operation.

Selection Notes

Select based on required accuracy; the KG variant offers 0.5% max log conformity compared to 1.0% for the JG model. Consider the integrated uncommitted op amp for system simplification. Evaluate frequency response requirements against signal levels, as bandwidth varies significantly with input magnitude.

Part Context

This component belongs to the Burr-Brown family now managed by Texas Instruments. It represents a specialized analog signal processing solution designed for high-dynamic-range applications requiring accurate logarithmic conversion without external complex circuitry.

Replacement Considerations

Public confirmed substitute part numbers: None.