STMicroelectronics LM334Z

Overview

LM334Z from STMicroelectronics is a three-terminal adjustable current source in TO-92 plastic package, delivering programmable output current from 1 µA to 10 mA with ±3% initial accuracy, 0.02%/V regulation, and operation across 1 V to 40 V supply range. It serves as a precision bias generator, temperature-sensing current source, or low-drift reference in analog front-ends and sensor conditioning circuits.

For engineers reviewing the LM334Z datasheet, LM334Z pinout, LM334Z application, or LM334Z equivalent, this page provides verified pin functions, thermal coefficient behavior (0.33%/°C), minimum operating voltage (0.8 V at 2 µA), shunt capacitance (15 pF), and zero-drift calibration methods using external diode/resistor networks.

Technical Context

The LM334Z implements a temperature-compensated bandgap-derived reference that sets current via an external resistor (I_set = 67.7 mV / R_set at +25°C), with output directly proportional to absolute temperature (°K). Its internal architecture enables stable operation without additional components while supporting reverse voltage tolerance up to 20 V.

It exhibits 15 pF effective shunt capacitance and a maximum slew rate of 1 V/µs at 1 mA set current. Thermal self-heating degrades regulation above 100 µA - e.g., +1 V across device at 1 mA raises junction temperature by ≈0.4°C, inducing ~0.13% current shift due to inherent 0.33%/°C TC.

Key Specifications

Pinout & Package

LM334Z uses TO-92 plastic package (Z suffix), with bottom-view pinout: Pin 1 = ADJ, Pin 2 = V+, Pin 3 = V−. This through-hole package supports manual prototyping and board-level thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT3092IMS#PBF and REF200AU, LM334Z uniquely balances programmability, temperature-proportional output, and ultra-low-voltage operation in a TO-92 package - making it optimal for cost-sensitive, thermally aware analog designs requiring field calibration.

Availability

LM334Z is available at Aetrix Electronics and suitable for current source biasing, remote temperature sensing, low-voltage reference driving, and in-line current limiting requiring stable component supply across industrial, test equipment, and embedded sensor applications.

Supply support for LM334Z 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

The LM134/LM234/LM334 family was developed specifically for precision current sourcing and Kelvin-based temperature measurement, targeting applications where simplicity, thermal linearity, and minimal external components are critical design constraints.

FAQ

What is the minimum voltage required for LM334Z to regulate at 10 mA?

The LM334Z requires a minimum of 1 V across V+ and V− terminals to maintain regulation at 1 mA ≤ I_set ≤ 5 mA. At 10 mA, regulation is specified down to 1 V per electrical characteristics table; however, thermal dissipation (P = V × I) must be managed - at 10 mA and 1 V, junction temperature rise in TO-92 exceeds safe limits without heatsinking.

Can LM334Z be used as a two-terminal current source?

Yes - by connecting ADJ and V− together, the LM334Z operates as a two-terminal device (anode/cathode), drawing current determined solely by the external resistor. This configuration retains ±3% accuracy but loses Kelvin-sensing capability and increases sensitivity to lead resistance and thermal gradients.

How does temperature affect LM334Z's output current beyond its designed 0.33%/°C coefficient?

Beyond the intentional 0.33%/°C TC, self-heating causes secondary drift: at 1 mA and +1 V across the device, junction temperature rises ≈0.4°C in still air, inducing ~0.13% current shift. This effect scales with power dissipation and ambient airflow - PCB copper area and forced convection mitigate it.

Is LM334Z compatible with lead-free reflow soldering processes?

Yes - LM334Z is supplied in ECOPACK®-compliant TO-92 packages with lead-free second-level interconnects. It meets JEDEC J-STD-020 moisture sensitivity level (MSL) requirements for standard reflow profiles, including peak temperatures up to 260°C for 10 seconds, as confirmed in ST's package documentation.