Texas Instruments LM134H/NOPB

Overview

LM134H/NOPB 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 64 mV sense voltage at 25°C and +0.33%/°C temperature coefficient enable direct Kelvin-proportional current output.

For engineers reviewing the LM134H/NOPB datasheet, LM134H/NOPB pinout, LM134H/NOPB application, or LM134H/NOPB equivalent, this device serves as a true floating two-terminal current source ideal for remote temperature sensing, LED biasing, ramp generation, and high-impedance active load design where lead resistance immunity and wide dynamic voltage range are critical.

Technical Context

The LM134H/NOPB implements a precision bandgap-derived reference with internal thermal compensation, establishing set current via external resistor R_SET using I_SET = 67.7 mV / R_SET at 25°C. Its architecture supports true 2-terminal operation without separate power rails, drawing only microampere-level bias current (I_BIAS) that scales with I_SET.

Reverse voltage tolerance up to 20 V enables AC-coupled operation as both rectifier and current source. The device exhibits 15 pF effective shunt capacitance and requires physical proximity of R_SET to minimize thermocouple/lead resistance errors - contact resistance >0.7 Ω reduces 1 mA output by 1%.

Key Specifications

Pinout & Package

LM134H/NOPB uses the TO-99 metal can package (Package Number NDV), a hermetically sealed 3-pin through-hole package with center-tab grounding. Pin 1 is the V+ terminal, Pin 2 is the V− (anode) terminal, and Pin 3 is the SET terminal - all pins are electrically isolated from the case, which is connected internally to V−.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM334Z/NOPB, LM134H/NOPB offers extended temperature range and hermetic reliability; compared with REF200AU, it provides wider programmability (1 μA–10 mA vs. fixed 100 μA) and higher voltage compliance (40 V vs. 45 V), but trades off initial accuracy and regulation performance.

Availability

LM134H/NOPB is available at Aetrix Electronics and suitable for remote temperature sensing, LED biasing, ramp generation, and micropower reference applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LM134H/NOPB 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 for industrial, automotive, and aerospace markets.

The LM134 family was designed as a precision, temperature-compensated current source for demanding analog signal conditioning, sensor interfacing, and biasing tasks where stability, wide voltage range, and hermetic packaging are essential.

FAQ

What is the minimum operating voltage for LM134H/NOPB at 1 mA set current?

The LM134H/NOPB requires a minimum of 1.0 V across its terminals (V+ to V−) to maintain regulation at 1 mA set current. This is defined by the internal 64 mV sense voltage plus headroom for bias circuitry. Below this voltage, current regulation degrades rapidly and the device enters dropout.

How does LM134H/NOPB achieve temperature-proportional current output?

The LM134H/NOPB generates current directly proportional to absolute temperature (°K) via an internal bandgap reference whose voltage scales linearly with temperature. At 25°C (298 K), the sense voltage is 64 mV; thus I_SET = (64 mV / R_SET) × (T / 298), enabling accurate remote temperature measurement without calibration drift.

Can LM134H/NOPB be used in AC applications?

Yes - the LM134H/NOPB tolerates reverse voltages up to 20 V while drawing only a few dozen microamperes, allowing it to function as both a rectifier and current source in AC-coupled circuits. In half-wave configurations, it delivers regulated current during positive half-cycles and blocks current with minimal leakage during negative half-cycles.

What is the role of the SET pin on LM134H/NOPB?

The SET pin on LM134H/NOPB is the current programming node where an external resistor (R_SET) connects to establish the output current. It senses a fixed 64 mV reference at 25°C, so I_SET ≈ 67.7 mV / R_SET. Physical proximity to the device is critical - lead resistance >0.7 Ω introduces >1% error at 1 mA.

Is LM134H/NOPB RoHS compliant?

Yes, LM134H/NOPB is RoHS compliant (Pb-free, halogen-free). The "NOPB" suffix explicitly denotes lead-free finish per JEDEC J-STD-609. It meets TI's RoHS standards and carries Level-1 MSL rating with unlimited floor life under dry pack conditions.