Texas Instruments LM234Z-3/NOPB

Overview

LM234Z-3/NOPB from Texas Instruments is a 3-terminal adjustable current source optimized for precision temperature sensing and remote biasing applications. It delivers programmable current from 1 μA to 10 mA with ±3% initial accuracy, operates from 1 V to 30 V, exhibits 0.02%/V current regulation, and features true 2-terminal operation with no external power supply required. Its output current is directly proportional to absolute temperature (°K), enabling accurate remote temperature measurement in industrial sensor nodes.

For engineers reviewing the LM234Z-3/NOPB datasheet, LM234Z-3/NOPB pinout, LM234Z-3/NOPB application, or LM234Z-3/NOPB equivalent, this device serves as a calibrated temperature sensor (±3°C initial error) and low-power current reference-critical for thermistor replacement, LED biasing, ramp generation, and surge-protected analog front-ends where wire resistance immunity and minimal quiescent current matter.

Technical Context

The LM234Z-3/NOPB implements a floating two-terminal current source architecture using an internal bandgap-derived reference and temperature-proportional voltage (67.7 mV at 25°C). Its current output follows I_SET = 67.7 mV / R_SET × (T / 298 K), enabling direct Kelvin-scale temperature sensing without offset calibration.

It supports true 2-terminal operation with reverse voltage tolerance up to 20 V, draws only microamperes in reverse bias, and maintains stable regulation across its −25°C to +100°C operating range. The device requires no additional components for basic function-only one external resistor sets current-and achieves zero-drift operation when augmented with a diode and second resistor.

Key Specifications

Pinout & Package

LM234Z-3/NOPB is housed in a TO-92 plastic package (Package Drawing LP), with 3 leads arranged in standard bottom-view configuration: Pin 1 (V+), Pin 2 (V−), Pin 3 (SET). This through-hole package supports manual assembly and prototyping while delivering thermal resistance of 180°C/W (junction-to-ambient, 0.4″ leads).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM334Z/NOPB and REF200AU, the LM234Z-3/NOPB uniquely combines programmable current, guaranteed ±3°C temperature sensor accuracy, and industrial −25°C to +100°C operation-making it the only choice for calibrated remote sensing in harsh environments.

Availability

LM234Z-3/NOPB is available at Aetrix Electronics and suitable for industrial temperature monitoring, LED driver circuits, precision ramp generators, and low-power analog bias networks requiring stable component supply and long-term BOM continuity.

Supply support for LM234Z-3/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 and embedded processing technologies, with decades of expertise in precision analog ICs and industrial-grade signal conditioning solutions.

The LM234 series belongs to TI's precision current source product line, designed specifically for applications demanding temperature-proportional current output, remote sensing immunity, and minimal external component count in industrial, test, and sensor systems.

FAQ

What is the primary function of the LM234Z-3/NOPB?

The LM234Z-3/NOPB is a 3-terminal adjustable current source engineered for precision temperature sensing and programmable biasing. Its core function is to deliver a current output directly proportional to absolute temperature (I ∝ T), with guaranteed ±3°C initial accuracy. Unlike generic current sources, the LM234Z-3/NOPB is explicitly characterized and binned as a temperature sensor-making it suitable for calibrated remote sensing without external compensation. This behavior is intrinsic to its internal architecture and confirmed in TI's SNVS746E datasheet.

How does the LM234Z-3/NOPB differ from the standard LM234?

The LM234Z-3/NOPB is a specific variant of the LM234 family, designated as a fully specified temperature sensor with ensured initial accuracy of ±3°C at 25°C. While the base LM234 offers general current-source functionality, the "Z-3" suffix indicates factory-tested thermal performance compliance-including tighter bounds on temperature coefficient (0.98T to 1.02T) and set-current error (±1% to ±2%). This makes the LM234Z-3/NOPB appropriate for applications where traceable temperature measurement is required, whereas the unqualified LM234 may be used where only current regulation matters.

Can the LM234Z-3/NOPB operate as a 2-terminal device?

Yes, the LM234Z-3/NOPB supports true 2-terminal operation-meaning it functions as a current source with only two connections (V+ and V−), eliminating the need for a separate power supply or ground reference. In this mode, the SET pin is internally biased, and current flows between V+ and V− terminals. This configuration is essential for remote temperature sensing over long wires, as it removes sensitivity to lead resistance. The datasheet confirms this capability in both the Description and Applications sections, citing "true 2-terminal operation" as a key feature.

What is the minimum operating voltage for the LM234Z-3/NOPB?

The LM234Z-3/NOPB has a minimum operating voltage of 0.9 V when the set current is between 100 μA and 1 mA-its typical operating range for temperature sensing applications. Below this voltage, regulation degrades and current output becomes unstable. This low dropout enables use in energy-harvesting and battery-depleted scenarios. The value is specified in the Electrical Characteristics table under "Minimum Operating Voltage" for the LM234-3 variant and verified across multiple test conditions in TI's SNVS746E datasheet.

Is the LM234Z-3/NOPB RoHS compliant?

Yes, the LM234Z-3/NOPB is RoHS compliant, as confirmed in TI's official Package Option Addendum. The "/NOPB" suffix explicitly denotes lead-free (Pb-free) construction, and the part is listed with RoHS = "Yes" under material compliance. It uses matte tin (Sn) lead finish and meets JEDEC standards for environmentally restricted substances. This compliance applies to all active manufacturing lots shipped by TI and distributed through authorized channels.