Analog Devices Inc. LM334S8#PBF

Overview

LM334S8#PBF from Analog Devices (formerly Linear Technology) is a 3-terminal adjustable current source and linear temperature sensor in an 8-lead SOIC package. It delivers precisely set current from 1 µA to 10 mA via external resistor R_SET, operates over 0.8 V to 30 V supply range, exhibits 0.02%/V regulation, and provides direct Kelvin-proportional output (0.336%/°C) for remote sensing applications such as cold-junction compensation and micropower bias networks.

For engineers reviewing the LM334S8#PBF datasheet, LM334S8#PBF pinout, LM334S8#PBF application, or LM334S8#PBF equivalent, key selection criteria include its two-terminal current-source operation without auxiliary power, low-voltage compliance down to 0.8 V, ±3°C accuracy variant availability, thermal coefficient stability, and compatibility with Kelvin-to-Celsius conversion circuits using external resistors and references.

Technical Context

The LM334S8#PBF implements a precision bandgap-derived reference voltage (~67.7 mV at 25°C) applied across an internal sense resistor, enabling current regulation proportional to absolute temperature. Its core architecture uses matched transistor pairs (Q1:Q2 = 17:1) to enforce I_SET = 67.7 mV / R_SET, with V– current fixed at 1/18 of total I_SET.

It functions as a true two-terminal device: only V+ and V– require connection for basic current-source operation, while the R terminal enables external calibration and feedback. Thermal self-heating effects are quantified (≈0.4°C per volt at 1 mA), and shunt capacitance is specified at 15 pF - both critical for high-impedance or AC-coupled designs.

Key Specifications

Pinout & Package

LM334S8#PBF is housed in an 8-lead plastic SOIC (narrow, 0.150") package (S8), with pins 1–4 and 5–8 arranged in dual rows. Only three terminals - V+, V–, and R - are electrically active; the remaining five pins (NC) are no-connects per manufacturer specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM334Z#PBF, LM334S8#PBF offers superior thermal dissipation (θ_JA = 80°C/W vs. 440°C/W) and surface-mount compatibility, while REF200AU#PBF trades programmability and thermal coefficient linearity for higher absolute accuracy and lower voltage sensitivity - making it suitable only for static bias roles.

Availability

LM334S8#PBF is available at Aetrix Electronics and suitable for cold-junction compensation, remote temperature sensing, micropower bias networks, and constant-gain bipolar stage design requiring stable component supply across industrial, test-and-measurement, and embedded sensor platforms.

Supply support for LM334S8#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 and maintains full product support, documentation, and manufacturing continuity for legacy Linear parts including the LM334 series.

The LM334S8#PBF belongs to Linear's precision current-source and temperature-sensor family, designed specifically for applications demanding Kelvin-proportional current output, low-voltage operation, and minimal external components - especially in remote sensing and micropower analog systems.

FAQ

What is the minimum operating voltage for LM334S8#PBF at 10 µA set current?

The LM334S8#PBF requires a minimum V+–V– voltage of 0.8 V when I_SET ≤ 100 µA, as confirmed in the Electrical Characteristics table on page 3 of the LM134 Series datasheet. At exactly 10 µA, this threshold holds - enabling operation from single-cell alkaline or lithium batteries even under load. The LM334S8#PBF maintains regulation down to this level without dropout or current collapse.

Can LM334S8#PBF be used as a zero-temperature-coefficient current source?

Yes - the LM334S8#PBF can achieve near-zero TC by adding an external diode and resistor network that cancels its inherent 0.336%/°C coefficient. Figure TA02 in the datasheet shows a proven topology using a matched diode and current mirror; slope error drops to <0.02%/°C after trimming. This configuration preserves LM334S8#PBF's core regulation while nullifying thermal drift for reference biasing.

How does the R pin function in LM334S8#PBF, and why is layout critical?

The R pin on LM334S8#PBF is internally held at ~67.7 mV and connects to R_SET to define I_SET. Because the sense voltage is sub-100 mV, trace resistance >0.7 Ω introduces >1% current error at 1 mA. Therefore, LM334S8#PBF requires R_SET to be placed adjacent to the R pin with short, wide copper; sockets and vias must be avoided to maintain accuracy.

What is the maximum power dissipation rating for LM334S8#PBF in SOIC package?

The LM334S8#PBF has a maximum power dissipation of 200 mW, as stated in the Absolute Maximum Ratings table (page 2). With θ_JA = 80°C/W and T_JMAX = 150°C, this allows up to ~125°C ambient rise before thermal shutdown - sufficient for most PCB layouts with moderate copper area. Derating is required above 70°C ambient per standard JEDEC guidelines.

Does LM334S8#PBF draw reverse current if V+ falls below V–?

No - the LM334S8#PBF draws no reverse current when V+ < V–, as explicitly noted in the Features list on page 1. This behavior prevents backfeeding into upstream circuitry during power sequencing or fault conditions, simplifying system-level protection design and improving reliability in multi-rail environments containing LM334S8#PBF.