Texas Instruments LF298H

Overview

LF298H from Texas Instruments is a monolithic BI-FET sample-and-hold IC designed for precision analog signal acquisition in data conversion systems. It delivers 0.002% typical gain accuracy, <10 µs acquisition time to 0.1%, and 0.5 mV typical hold step with 0.01 µF capacitor - enabling high-fidelity sampling in instrumentation-grade ADC front-ends and test equipment.

For engineers reviewing the LF298H datasheet, LF298H pinout, LF298H application, or LF298H equivalent, this page provides verified technical context, package-specific pin functions, real-world application mappings, and validated alternative options - all grounded in TI's SNOSBI3C (Rev. C, October 2018) production data sheet.

Technical Context

The LF298H operates as a unity-gain follower with bipolar input stage for low offset (1–3 mV typ) and wide bandwidth, while P-channel JFETs in the output stage achieve ultra-low droop (5 mV/min with 1 µF). Its differential logic interface accepts TTL/PMOS/CMOS with 1.4 V threshold and supports ±5 V to ±18 V dual supplies.

Hold mode isolates the input path completely - eliminating feedthrough even at rail-to-rail input signals - and maintains output impedance below 2 Ω. Input impedance exceeds 10¹⁰ Ω, enabling direct interfacing with high-impedance sensors without accuracy degradation.

Key Specifications

Pinout & Package

LF298H is supplied in an 8-pin TO-99 metal can package (body size 9.08 mm × 9.08 mm), rated for –25°C to +85°C ambient operation. The hermetically sealed package ensures stability in high-reliability test and aerospace environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar sample-and-hold applications.

Compared with LF198A-N and LF398-N, the LF298H occupies a mid-tier position: it offers better DC performance than LF398-N but lacks the extended temperature qualification of LF198A-N - making it optimal for industrial test gear requiring reliability at 85°C ambient without military-spec overhead.

Availability

LF298H is available at Aetrix Electronics and suitable for precision data acquisition, automated test equipment, and aerospace instrumentation requiring stable component supply across multi-year production cycles.

Supply support for LF298H includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with over 50 years of innovation in precision signal chain components.

The LF298H belongs to TI's LFx98x monolithic sample-and-hold family, engineered for ultrahigh DC accuracy and fast acquisition in metrology-grade measurement systems and high-speed data converters.

FAQ

What is the maximum operating temperature for the LF298H?

The LF298H has a specified operating ambient temperature range of –25°C to +85°C. Its maximum junction temperature is 115°C, and thermal derating must be applied above 85°C ambient using RθJA = 85°C/W (TO-99 package). This makes LF298H suitable for enclosed industrial enclosures but not for under-hood automotive use.

Can the LF298H operate from a single supply?

No, the LF298H requires dual symmetric supplies (e.g., ±12 V or ±15 V) to function correctly. Its internal BI-FET architecture and rail-to-rail input/output capability depend on balanced positive and negative rails. Single-supply operation is not supported and will result in undefined behavior or damage.

What hold capacitor value is recommended for minimal droop in a 1-second hold application?

For ≤5 mV droop over 1 second, a 1 µF polypropylene capacitor is recommended. At 100 pA leakage (max), droop = I × t / C ≈ (100 × 10⁻¹² A × 1 s) / 10⁻⁶ F = 0.1 mV - well within specification. Avoid ceramic dielectrics due to dielectric absorption; prefer polypropylene or Teflon for metrology-grade stability.

How does the OFFSET ADJUST pin affect input offset drift in the LF298H?

The OFFSET ADJUST pin in the LF298H enables DC nulling without degrading input offset drift performance. Unlike resistor-based trimming methods, TI's internal design ensures that adjustment does not introduce additional thermal coefficients - maintaining typical drift of <1 µV/°C across the –25°C to +85°C range.

Is the LF298H pin-compatible with the LF198-N or LF398-N?

Yes, the LF298H shares identical pin configuration and function mapping with LF198-N and LF398-N in the TO-99 (LMC) package - all use the same 8-pin layout with V+, OFFSET ADJUST, INPUT, V–, OUTPUT, Ch, LOGIC REFERENCE, and LOGIC pins. However, electrical specifications differ, so functional substitution requires validation against target accuracy and temperature requirements.