LF198WG-QMLV

Overview

The LF198WG-QMLV is a monolithic sample-and-hold circuit utilizing BI-FET technology, designed for high-precision analog signal processing. It operates from ±5V to ±18V supplies and achieves an acquisition time of less than 10 μs. The device provides a typical DC gain accuracy of 0.002% and maintains a low droop rate of 5 mV/min with a 1 μF hold capacitor. Input impedance reaches 10^10 Ω, supporting high source impedances without degrading accuracy. Logic inputs are fully differential with a 1.4 V threshold, ensuring compatibility with TTL, PMOS, and CMOS standards.

Feature Summary

• BI-FET technology enables ultra-high dc accuracy combined with fast signal acquisition and minimal droop rates.
• Wide bandwidth allows integration within the feedback loop of 1 MHz operational amplifiers without stability issues.
• Fully differential logic inputs feature low input current and direct compatibility with standard digital logic families.
• P-channel junction FET output stage ensures extremely low noise and eliminates high-temperature instabilities.

Applications

• Data acquisition systems requiring precise signal sampling
• Analog-to-digital conversion front-end circuits
• Synchronous demodulation applications
• Automatic test equipment

Procurement Notes

Verify that the specific ordering suffix matches the required military or space qualification level. Confirm package type and lead finish specifications against the latest TI Package Option Addendum. Ensure compliance with RoHS exemptions if applicable. Validate operating temperature ranges and supply voltage requirements prior to procurement.

Selection Notes

Evaluate the trade-off between acquisition time and hold capacitor selection based on application speed. Consider dielectric absorption characteristics of the external hold capacitor to minimize hysteresis errors. Verify logic signal rise times meet minimum dV/dt requirements to prevent excessive hold step. Assess power dissipation limits at elevated ambient temperatures.

Part Context

This component belongs to the LF198QML family of monolithic sample-and-hold circuits manufactured by Texas Instruments. The series includes variants such as LF198H/883 and LF198JAN, all sharing core BI-FET architecture. These devices are engineered for environments demanding high reliability and precision analog performance under strict electrical constraints.

Replacement Considerations

Public confirmed substitute part numbers include LF198H/883 and LF198JAN. Verify pinout compatibility and electrical parameter alignment before substitution. Ensure replacement parts meet the same military or space qualification standards required by the design.