Texas Instruments LM285D-1-2

Overview

LM285D-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, 10 μA to 20 mA operating current range, and 1.5 Ω max reference impedance over full temperature range (–40°C to 85°C). It serves as a precision shunt reference in portable battery-powered analog systems requiring long shelf-life operation.

For engineers reviewing the LM285D-1-2 datasheet, LM285D-1-2 pinout, LM285D-1-2 application, or LM285D-1-2 equivalent, this page provides verified electrical specs, SOIC-8 package details, real-world use cases in portable instrumentation, and validated alternative options for low-power reference design.

Technical Context

The LM285D-1-2 operates as a floating shunt reference, regulating voltage between cathode and anode via internal band-gap core and high-gain amplifier. Regulation initiates only after minimum cathode current (8 μA) is supplied, enabling stable operation across capacitive loads without external compensation.

Its design features on-chip trimming for 1% initial voltage tolerance, low broadband noise (60 μV RMS, 10 Hz–10 kHz), and exceptional capacitive loading tolerance-making it suitable for noisy, space-constrained portable systems where layout simplicity and power efficiency are critical.

Key Specifications

Pinout & Package

LM285D-1-2 is housed in an 8-pin SOIC (Package Drawing D), body size 4.90 mm × 3.91 mm, with 1.75 mm max height and RoHS-compliant NiPdAu lead finish. The device uses a two-terminal shunt topology with dedicated anode and cathode pins; three NC pins simplify PCB routing and reduce parasitic coupling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM285D-1-2, LM385D-1-2 trades extended temperature range for reduced minimum current requirement, while LM385BD-1-2 delivers higher initial accuracy at the cost of slightly higher quiescent current-enabling selection based on thermal, power, or precision priority.

Availability

LM285D-1-2 is available at Aetrix Electronics and suitable for portable meter references, battery-operated systems, and current-loop instrumentation requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for LM285D-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 specializing in analog and embedded processing technologies, with over 50 years of leadership in precision analog ICs.

The LMx85 family was designed specifically for micropower, two-terminal shunt voltage reference applications in portable, battery-constrained systems-emphasizing low drift, wide current range, and robust capacitive-load stability.

FAQ

What is the minimum cathode current required for LM285D-1-2 to regulate properly?

The LM285D-1-2 requires a minimum cathode current (I_Z(min)) of 8 μA to initiate and maintain regulation across its full operating temperature range (–40°C to 85°C). This value is specified in the Electrical Characteristics table and confirmed in the Recommended Operating Conditions section of the TI SLVS075J datasheet. Below 8 μA, the output voltage deviates significantly from 1.235 V, making LM285D-1-2 unsuitable for sub-microamp biasing scenarios.

Does LM285D-1-2 support operation with large bypass capacitors?

Yes, LM285D-1-2 is explicitly designed for unconditional stability with any value of cathode bypass capacitor-including 10 μF tantalum or 100 μF electrolytic types-due to internal frequency compensation. Unlike many shunt references, LM285D-1-2 does not require series resistance or external RC networks to prevent oscillation, simplifying layout in space-constrained portable designs.

What is the long-term stability performance of LM285D-1-2?

LM285D-1-2 exhibits a long-term drift of ±20 ppm per kilohour (±20 ppm/khr) when operated at 25°C with 100 μA cathode current, as measured per JEDEC JESD22-A117. This translates to approximately ±0.18% total drift over 10 years of continuous operation-making LM285D-1-2 suitable for uncalibrated field-deployed instrumentation where recalibration intervals exceed five years.

Can LM285D-1-2 be used in negative-voltage reference configurations?

Yes, LM285D-1-2's floating shunt architecture allows it to function as a negative reference: connect the anode to the negative rail and source current into the cathode referenced to system ground. This configuration is documented in TI's Application and Implementation section (Figure 11) and leverages the device's bidirectional current capability-enabling precision biasing in dual-supply op-amp circuits without additional level-shifting components.

How does LM285D-1-2 compare to LM385-1.2 in terms of temperature range and current requirements?

LM285D-1-2 is rated for –40°C to +85°C operation with a minimum cathode current of 8 μA, whereas LM385-1.2 is specified for 0°C to +70°C and requires 15 μA minimum current. Both share identical nominal voltage (1.235 V), impedance (1.5 Ω max), and noise (60 μV), but LM285D-1-2 offers broader environmental coverage and lower startup current-critical for industrial and extended-life battery applications.