Texas Instruments LM134 MDC

Overview

LM134 MDC from Texas Instruments is a 3-terminal adjustable current source optimized for precision biasing, temperature sensing, and low-power reference applications across −55°C to +125°C. It delivers programmable current from 1 μA to 10 mA with ±3% initial accuracy, 0.02%/V current regulation, and operates over 1 V to 40 V supply range. Its true 2-terminal operation enables use in remote sensor circuits where lead resistance must not affect accuracy.

For engineers reviewing the LM134 MDC datasheet, LM134 MDC pinout, LM134 MDC application, or LM134 MDC equivalent, this page provides verified technical context, validated pin functions, real-world application cards, and two confirmed alternative parts - all grounded in TI's SNVS746E specification and package documentation.

Technical Context

The LM134 MDC implements a floating current source architecture with no separate power supply pins: current flows between V+ and V− terminals, while the SET terminal establishes current via external resistor R_SET. Its core sense voltage is 67.7 mV at 25°C (64 mV nominal), directly proportional to absolute temperature (≈+0.336%/°C), enabling intrinsic Kelvin-scale temperature transduction.

It supports true 2-terminal operation with reverse voltage tolerance up to 20 V, draws only microamperes in reverse bias, and exhibits 15 pF shunt capacitance. Minimum operating voltage ranges from 0.8 V (at I_SET ≤ 100 μA) to 1.0 V (at I_SET > 1 mA), making it suitable for micropower systems with tight voltage margins.

Key Specifications

Pinout & Package

LM134 MDC is supplied as a die (DIESALE) without leadframe or molded package - intended for hybrid assembly, chip-on-board (COB), or custom substrate integration. It has three terminals: V+, V−, and SET. No standard surface-mount or through-hole package is assigned; pinout corresponds directly to functional roles on the bare die.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable current source applications.

Compared with LM134 MDC, LM334Z/NOPB offers plug-and-play TO-92 usability but sacrifices military-grade temperature range, while LM234Z-3/NOPB delivers certified thermal accuracy at the expense of programmable current flexibility and extended cold-temperature operation.

Availability

LM134 MDC is available at Aetrix Electronics and suitable for remote temperature sensing, micropower reference design, and high-reliability current biasing requiring stable component supply across aerospace, downhole instrumentation, and extended-temperature industrial control systems.

Supply support for LM134 MDC 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, embedded processing, and high-reliability components, with decades of heritage in precision analog ICs and industrial-grade signal conditioning.

The LM134 family belongs to TI's precision current source product line, engineered for applications demanding Kelvin-proportional current output, wide supply range, and robust operation in thermally extreme or electrically noisy environments.

FAQ

What is the exact pin configuration and package type of LM134 MDC?

LM134 MDC is a die-only product (DIESALE material type) with no molded package or leadframe. It has three functional terminals - V+, V−, and SET - arranged for wire-bond or flip-chip integration onto custom substrates. TI does not assign mechanical package dimensions or pin numbering; physical layout follows the internal schematic topology shown in Figure 13 of SNVS746E.

Does LM134 MDC support true 2-terminal operation, and how is it implemented?

Yes, LM134 MDC supports true 2-terminal operation: current flows between V+ and V−, while the SET terminal remains externally biased via a resistor to V−. In this mode, the device functions as a floating current source with no ground reference required - enabling use in isolated sensor bridges, high-side current sinks, and AC-coupled bias networks without additional supply rails.

What is the temperature coefficient of LM134 MDC, and how is it used in sensing applications?

LM134 MDC has a temperature coefficient of +0.336%/°C, meaning its output current increases linearly with absolute temperature (Kelvin). This allows direct conversion of temperature to current: I_SET = I₀ × (T / T₀). At 25°C (298.15 K), 100 μA output corresponds to 100 μA × (T / 298.15), enabling remote sensing with no calibration offset error - only gain adjustment needed.

Can LM134 MDC be used in reverse-bias conditions, and what are the limits?

Yes, LM134 MDC tolerates reverse voltage (V− higher than V+) up to 20 V. Under reverse bias, it draws only a few dozen microamperes - functioning as a low-leakage rectifier while maintaining current-source integrity during AC or bidirectional supply conditions. This behavior is explicitly characterized in Absolute Maximum Ratings and enables use in AC-powered current sources.

How do I calculate the external resistor value for a desired set current with LM134 MDC?

Use the formula R_SET = 67.7 mV / I_SET (at 25°C), where I_SET is the target current. For example, for 1 mA output, R_SET = 67.7 Ω. Note that LM134 MDC's bias current adds ~5.9% error at low currents; for highest accuracy, apply the correction factor from Equation (2) in SNVS746E Section "Calculating R_SET".