Analog Devices Inc. LM334Z#PBF

Overview

LM334Z#PBF from Analog Devices (formerly Linear Technology) is a 3-terminal adjustable current source and linear temperature sensor in TO-92 plastic package, operating from 1 µA to 10 mA with 0.02%/V regulation, 0.8 V to 30 V compliance voltage, and ±3°C temperature accuracy (at 100 µA–1 mA range). It serves as a micropower bias network, cold-junction compensator, or Kelvin-scale remote temperature transducer in industrial instrumentation.

For engineers reviewing the LM334Z#PBF datasheet, LM334Z#PBF pinout, LM334Z#PBF application, or LM334Z#PBF equivalent, key selection criteria include its absolute-temperature-proportional output (0.336%/°C), low-voltage operation down to 0.8 V, absence of reverse current, and compatibility with standard transistor PCB footprints for cost-sensitive embedded sensing.

Technical Context

The LM334Z#PBF implements a precision two-terminal current source using an internal 67.7 mV reference voltage directly proportional to absolute temperature (°K), enabling simultaneous use as a current regulator and linear temperature sensor. Its core architecture includes matched transistors (17:1 ratio) and an operational amplifier that forces the R pin to 64 mV, yielding I_SET = 67.7 mV / R_SET at 25°C.

Thermal self-heating effects are explicitly characterized: at 1 mA and 1 V drop, junction temperature rises ≈0.4°C in still air, inducing ≈0.132% current shift due to the 0.33%/°C coefficient. Shunt capacitance is fixed at 15 pF, and start-up time ranges from 1.25 ms (low-IDSS FETs) to sub-microsecond under typical bias conditions.

Key Specifications

Pinout & Package

Z Package: 3-lead plastic TO-92 (similar to TO-226), through-hole mounting, lead diameter 0.016–0.024 inch for solder dip finish, body dimensions 0.180" × 0.180" × 0.500".

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current source and temperature sensor applications.

Compared with LM334Z#PBF, LM334Z offers identical performance but non-RoHS-compliant finish, while REF200AU trades temperature linearity and 0.8 V operation for tighter regulation and higher voltage headroom-making LM334Z#PBF uniquely suited for dual-role sensing/biasing in space- and power-constrained systems.

Availability

LM334Z#PBF is available at Aetrix Electronics and suitable for industrial temperature monitoring, micropower sensor interface, and cold-junction compensation requiring stable component supply across extended product lifecycles.

Supply support for LM334Z#PBF 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

Analog Devices acquired Linear Technology in 2017; Linear pioneered high-performance analog ICs for precision signal conditioning, power management, and sensing.

The LM134 Series-including LM334Z#PBF-is designed for applications demanding both accurate current regulation and linear temperature transduction in compact, low-cost packages for industrial, instrumentation, and embedded systems.

FAQ

What is the minimum operating voltage for LM334Z#PBF?

The LM334Z#PBF has a minimum operating voltage of 0.8 V at I_SET ≤ 100 µA, rising to 1.0 V at I_SET > 1 mA. This low threshold enables direct operation from single NiMH or Li-ion cells and complements ultra-low-voltage microcontrollers. The LM334Z#PBF achieves regulation by maintaining 64 mV across the R pin relative to V–, requiring sufficient headroom for internal transistor saturation.

Can LM334Z#PBF be used as a temperature sensor without external components?

Yes-the LM334Z#PBF functions as a self-contained Kelvin-scale temperature sensor: its output current increases linearly with absolute temperature (I_SET ∝ T_°K) at 0.336%/°C. At 298 µA bias, it delivers exactly 1 µA/°K, requiring only a termination resistor (e.g., 10 kΩ) to convert to 10 mV/°K voltage output. No op-amps or calibration ICs are needed for basic operation, though trimming improves accuracy.

Does LM334Z#PBF draw reverse current when V+ is grounded?

No-the LM334Z#PBF draws zero reverse current under reverse-bias conditions (V+ < V–), a documented feature critical for protecting downstream circuitry during power sequencing or fault events. This behavior is confirmed in Absolute Maximum Ratings (V+ to V– reverse voltage = 20 V) and Electrical Characteristics tables, where reverse leakage is specified as "no reverse current." The LM334Z#PBF achieves this via internal diode isolation and FET-based biasing.

What is the temperature accuracy specification for LM334Z#PBF?

The LM334Z#PBF is specified with ±3°C equivalent temperature error over the 100 µA to 1 mA operating range at 25°C, corresponding to ±1% set-current error. This accuracy holds across its full 0°C to 70°C operating temperature range and is traceable to the device's 0.96–1.04 ratio of set-current temperature dependence (per Electrical Characteristics table). The LM334Z#PBF does not carry the "-3" suffix (e.g., LM334Z-3), but its datasheet confirms this tolerance applies to the base LM334 grade.

How do I calculate the R_SET value for a desired LM334Z#PBF current?

Use the formula R_SET = 67.7 mV / I_SET, where I_SET is the target current in amperes at 25°C. For example, to achieve 298 µA (for 1 µA/°K temperature sensing), R_SET = 67.7 mV / 0.000298 A = 227 Ω (standard 226 Ω resistor yields 299 µA). The LM334Z#PBF's internal reference scales precisely with absolute temperature, so this relationship remains valid across its operating range.