Texas Instruments LM334SM/NOPB

Overview

LM334SM/NOPB from Texas Instruments is a 3-terminal adjustable current source optimized for precision temperature sensing and low-power biasing in 0°C to +70°C industrial environments. It delivers programmable current from 1 μA to 10 mA with ±3% initial accuracy, 0.02%/V current regulation, and operates across 1 V to 40 V supply range. Its true 2-terminal operation enables use in remote sensor circuits where lead resistance must not affect accuracy.

For engineers reviewing the LM334SM/NOPB datasheet, LM334SM/NOPB pinout, LM334SM/NOPB application, or LM334SM/NOPB equivalent, this device is selected for stable current sourcing in analog front-ends, LED biasing, ramp generation, and Kelvin-sensing temperature measurement systems requiring minimal external components and no separate power rail.

Technical Context

The LM334SM/NOPB implements a floating current source architecture using an internal bandgap-referenced sense voltage of 67.7 mV at 25°C, directly proportional to absolute temperature (≈+0.336%/°C). Its output current is set by a single external resistor without auxiliary components, enabling true 2-terminal operation.

It features reverse-voltage tolerance up to 20 V, draws only microamperes in reverse bias, and maintains regulation over its full 1–40 V dynamic range. The SOIC-8 package supports surface-mount assembly with MSL Level-1 reflow compatibility and 0°C to +70°C operating temperature specification.

Key Specifications

Pinout & Package

LM334SM/NOPB uses the SOIC-8 package (TI Package D), measuring 4.9 mm × 3.9 mm × 1.75 mm, with 1.27 mm pitch and gull-wing leads. Pin 1 is marked by a beveled corner or dot; devices are shipped in tubes (95 pcs) with Q1 quadrant orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM334Z/NOPB, LM334SM/NOPB offers superior board-space efficiency and thermal performance in SMT production; versus REF200AU, it provides full programmability and Kelvin-proportional output at the cost of lower base accuracy and single-output topology.

Availability

LM334SM/NOPB is available at Aetrix Electronics and suitable for remote temperature sensing, LED biasing, ramp generation, and low-power reference driver applications requiring stable component supply across industrial design cycles.

Supply support for LM334SM/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 connectivity technologies, with decades of heritage in precision analog ICs.

The LM334 family was designed specifically for applications demanding accurate, temperature-aware current sourcing in resource-constrained analog systems-emphasizing simplicity, 2-terminal operation, and Kelvin-scale sensing fidelity.

FAQ

What is the correct formula to calculate R_SET for a target current with LM334SM/NOPB?

The nominal relationship is R_SET = 67.7 mV / I_SET at 25°C. For example, to set 1 mA, use R_SET = 67.7 Ω. Note that I_SET increases by ≈0.336%/°C above 25°C, so R_SET must be a low-tempco resistor (e.g., <20 ppm/°C metal film) to maintain accuracy across temperature. The LM334SM/NOPB datasheet Figure 13 shows the basic connection.

Can LM334SM/NOPB operate as a 2-terminal device in series with a load?

Yes-LM334SM/NOPB supports true 2-terminal operation: connect V+ to the positive rail and V− to the load's return, with R_SET between V− and ground. Current flows from V+ through the load into V−, then internally to R_SET. This configuration requires no additional supply connections and preserves accuracy even with long wires, making it ideal for remote sensing. The LM334SM/NOPB pinout confirms V+ and V− as the functional terminals.

What is the maximum power dissipation limit for LM334SM/NOPB in SOIC-8 package?

The absolute maximum power dissipation for LM334SM/NOPB is 400 mW. In SOIC-8 (θ_JA = 165°C/W), this corresponds to a maximum allowable junction-to-ambient temperature rise of 66°C at full dissipation. At 25°C ambient, safe continuous operation requires limiting (V+ − V−) × I_SET < 400 mW-e.g., 40 V × 10 mA = 400 mW is the theoretical max, but derating is recommended for reliability. Thermal data for LM334SM/NOPB is specified in TI SNVS746E.

Does LM334SM/NOPB require decoupling capacitors for stable operation?

LM334SM/NOPB does not require input decoupling for DC stability, but a 100 nF ceramic capacitor from V+ to V− is recommended when driving capacitive loads or operating near switching noise sources. The 15 pF internal shunt capacitance can interact with long traces or high-impedance loads, causing instability; buffering with a FET (Figure 30) reduces effective capacitance to <3 pF. Layout guidance for LM334SM/NOPB emphasizes short R_SET traces and avoidance of sockets.

How does LM334SM/NOPB differ from LM234 and LM134 in terms of temperature range and packaging?

LM334SM/NOPB is rated for 0°C to +70°C operation and supplied only in SOIC-8 (D) package. LM234 covers −25°C to +100°C and is offered in TO-92 (LP) and SOIC-8; LM134 spans −55°C to +125°C in TO-metal-can (NDV). All share identical core electrical behavior, but LM334SM/NOPB is optimized for commercial-grade SMT applications. The LM334SM/NOPB marking "SM" explicitly denotes the SOIC-8 variant per TI's ordering nomenclature.