Texas Instruments LM385BLPRE3-1-2

Overview

LM385BLPRE3-1-2 from Texas Instruments is a micropower, two-terminal band-gap voltage reference delivering 1.235 V nominal output with ±20 ppm/°C temperature coefficient, 15 μA to 20 mA operating current range, and 1.5 Ω max reference impedance over full temperature range (0°C to 70°C). It serves as a precision shunt reference in battery-powered analog signal chains and portable instrumentation.

For engineers reviewing the LM385BLPRE3-1-2 datasheet, LM385BLPRE3-1-2 pinout, LM385BLPRE3-1-2 application, or LM385BLPRE3-1-2 equivalent, key selection criteria include initial voltage tolerance (1.223–1.247 V at 25°C), long-term stability (±20 ppm/khr), low-noise operation (60 µV broadband), capacitive load tolerance, and TO-92 package compatibility with space-constrained PCB layouts.

Technical Context

The LM385BLPRE3-1-2 implements a floating shunt topology with internal band-gap core, high-gain amplifier, and frequency-compensated loop enabling stable regulation across all capacitor loads. Its design eliminates need for external compensation and supports both positive and negative regulation configurations.

It operates exclusively in fixed-voltage reference mode with no adjustability. Regulation requires minimum cathode current of 15 μA; below this threshold, output voltage deviates from specification. Thermal performance is characterized by 140 °C/W junction-to-ambient resistance in TO-92 (LP) package.

Key Specifications

Pinout & Package

LM385BLPRE3-1-2 uses TO-92 (LP) package: 3-pin through-hole, 4.30 mm × 4.30 mm body, formed leads, Pb-free SN finish, RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM385BDR-1-2 and TLVH431ACDBVR, the LM385BLPRE3-1-2 offers lowest assembly cost in low-volume portable designs, best mechanical reliability in vibration-prone handheld enclosures, and simplest bill-of-materials with zero external components required for basic operation.

Availability

LM385BLPRE3-1-2 is available at Aetrix Electronics and suitable for portable meter references, battery-operated systems, and current-loop instrumentation requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LM385BLPRE3-1-2 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 headquartered in Dallas, Texas, specializing in analog and embedded processing technologies with over 50 years of leadership in precision analog ICs.

The LM385B series belongs to TI's micropower voltage reference product line, engineered specifically for ultra-low-power, high-stability applications in portable and battery-critical systems where minimal quiescent current and long-term drift control are essential.

FAQ

What is the minimum operating current for LM385BLPRE3-1-2 to maintain regulation?

The LM385BLPRE3-1-2 requires a minimum cathode current of 15 μA to achieve specified voltage accuracy and regulation. Below this threshold, output voltage drops nonlinearly and temperature coefficient degrades. This value is confirmed in the Electrical Characteristics table of the SLVS075J datasheet under I_Z(min) for LM385B-1.2 devices. Operating the LM385BLPRE3-1-2 at 15 μA enables micropower sleep modes while retaining reference integrity.

Does LM385BLPRE3-1-2 require an external capacitor for stability?

No, the LM385BLPRE3-1-2 does not require an external capacitor for stability. Its internally compensated shunt architecture is explicitly designed to remain stable with any capacitive load, including direct connection to large bypass capacitors on the cathode node. This eliminates external components and simplifies layout - a key advantage documented in Section 8.3 Feature Description of the SLVS075J datasheet. The LM385BLPRE3-1-2 achieves this via built-in frequency compensation optimized for floating shunt operation.

What is the maximum operating temperature range for LM385BLPRE3-1-2?

The LM385BLPRE3-1-2 is rated for operation from 0°C to 70°C ambient temperature, as defined in the Recommended Operating Conditions table (Section 7.3) of the SLVS075J datasheet. This differs from the LM285-1.2 (−40°C to 85°C) and reflects its qualification for commercial-grade portable instrumentation. Junction temperature must remain below 150°C; with 140 °C/W thermal resistance in TO-92 package, power dissipation should be limited to ≤357 mW at 70°C ambient.

How does the LM385BLPRE3-1-2 compare to LM385-1.2 in terms of voltage tolerance?

The LM385BLPRE3-1-2 features tighter initial voltage tolerance than standard LM385-1.2: ±1% (1.223–1.247 V) versus ±2% (1.21–1.26 V) at 25°C. This improvement results from enhanced on-chip trimming during manufacturing, as stated in the Features section of SLVS075J. Both share identical temperature coefficient (±20 ppm/°C), impedance (1.5 Ω max), and noise (60 µV), making the LM385BLPRE3-1-2 the preferred choice where higher initial accuracy is critical without adding calibration steps.

Can LM385BLPRE3-1-2 be used in negative-reference configurations?

Yes, the LM385BLPRE3-1-2 supports negative-reference configurations due to its floating shunt architecture. As described in Section 8.3 Feature Description, the device functions as a two-terminal shunt regulator with no ground reference constraint - the anode can be tied to a negative rail while the cathode delivers a regulated voltage relative to that rail. This enables precision negative voltage generation or level-shifting in bipolar analog signal chains, provided cathode current remains within 15 μA–20 mA and power dissipation limits are observed.