Texas Instruments LM385BLPR-2-5

Overview

LM385BLPR-2-5 from Texas Instruments is a micropower, two-terminal, band-gap shunt voltage reference delivering a precise 2.5 V output with ±0.038 V (±1.5%) initial tolerance at 25°C, 20 μA–20 mA operating current range, and 1.5 Ω max reference impedance over 0°C to 70°C - used in portable meter references and battery-operated analog signal conditioning circuits.

For engineers reviewing the LM385BLPR-2-5 datasheet, LM385BLPR-2-5 pinout, LM385BLPR-2-5 application, or LM385BLPR-2-5 equivalent, key selection criteria include cathode current compliance (IZ(MIN) = 8–20 μA), low-temperature coefficient (±20 ppm/°C), broadband noise (120 µV, 10 Hz–10 kHz), and TO-92 package compatibility with space-constrained, low-power designs.

Technical Context

The LM385BLPR-2-5 implements a floating shunt architecture using an internal band-gap reference and high-gain amplifier to regulate voltage between cathode and anode. It operates as a two-terminal device requiring external current sourcing into the cathode, with regulation established only when cathode current exceeds IZ(MIN).

Its design includes on-chip trimming for tight voltage tolerance, internal frequency compensation for stable operation under capacitive loading up to 0.1 µF, and low dynamic impedance (≤1 Ω at 25°C, ≤1.5 Ω over full temperature range) enabling use in precision analog feedback paths and low-noise reference generation.

Key Specifications

Pinout & Package

LM385BLPR-2-5 is housed in a 3-pin TO-92 (LP) package with 4.30 mm × 4.30 mm body size and through-hole mounting. Pin 1 is ANODE (common, typically grounded); Pin 2 is CATHODE (shunt current/voltage input); Pin 3 is NC (no internal connection).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar shunt voltage reference applications.

Compared with LM385LP-2-5, LM385BLPR-2-5 delivers tighter initial accuracy for uncalibrated portable instruments; compared with TLVH431ACDBVR, it offers lower operating current and simpler two-terminal implementation at the cost of fixed output voltage.

Availability

LM385BLPR-2-5 is available at Aetrix Electronics and suitable for portable meter references, current-loop instrumentation, and battery-operated systems requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LM385BLPR-2-5 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 company specializing in analog and embedded processing technologies, with decades of leadership in precision analog ICs and voltage reference design.

The LM385B series was developed specifically for micropower, high-stability shunt references in portable and battery-constrained applications - emphasizing low current operation, tight tolerance, and robust thermal performance.

FAQ

What is the minimum cathode current required for regulation in the LM385BLPR-2-5?

The LM385BLPR-2-5 requires a minimum cathode current (IZ(MIN)) of 8–20 μA over its full operating temperature range (0°C to 70°C) to maintain regulation. At 25°C, regulation is guaranteed above 8 μA; design margins should target ≥20 μA to ensure stability across temperature extremes and unit-to-unit variation. Below this threshold, the output voltage drops nonlinearly and cannot be relied upon for precision applications.

Can the LM385BLPR-2-5 be used in negative-reference configurations?

Yes, the LM385BLPR-2-5 supports negative-reference configurations due to its floating shunt architecture. By connecting the ANODE to a positive rail and sourcing current into the CATHODE from ground (or a more negative node), it establishes −2.5 V relative to ANODE. This configuration is validated in TI's application notes for thermocouple cold-junction compensation and dual-supply sensor interfaces.

What is the maximum capacitive load the LM385BLPR-2-5 can drive without oscillation?

The LM385BLPR-2-5 is internally compensated to remain stable with up to 0.1 µF ceramic capacitance directly across the CATHODE–ANODE terminals. TI's layout guidelines confirm that no series resistor is needed for stabilization - unlike older shunt references - making it ideal for compact, low-noise PCB layouts where space and component count are constrained.

How does the LM385BLPR-2-5 differ from the standard LM385-2.5 in terms of specifications?

The LM385BLPR-2-5 is the "B-grade" variant of the LM385 family, featuring ±1.5% initial voltage tolerance (vs. ±3% for LM385-2.5) and tighter reference impedance (≤1 Ω at 25°C vs. ≤1 Ω for LM385-2.5, but same 1.5 Ω max over temperature). Both share identical operating current range, temperature coefficient (±20 ppm/°C), and TO-92 packaging - making LM385BLPR-2-5 the preferred choice for higher-accuracy portable instrumentation.

Is the LM385BLPR-2-5 RoHS compliant and lead-free?

Yes, the LM385BLPR-2-5 is RoHS compliant and features lead-free terminations. Per TI's Packaging Information table, it carries "Yes" in the RoHS column and uses "Call TI" for lead finish - indicating standard NiPdAu or matte tin plating per TI's qualified lead-free processes. The TO-92 (LP) package is exempt from MSL rating requirements due to its through-hole construction.