LM285D-1.2 Shunt Voltage Reference IC Equivalent & Substitute Parts

Part Overview

The LM285D-1.2 is a shunt voltage reference IC manufactured by onsemi, designed to provide a fixed 1.235V output with ±1% tolerance. This component is classified as a Power Management (PMIC) device in the 8-SOIC surface mount package. The main part is currently listed as obsolete, making equivalent and substitute parts essential for ongoing design support and production continuity. Shunt voltage references are critical in precision analog circuits requiring stable reference voltages for data acquisition, instrumentation, and power management applications.

Key Parameters

Parameter	Value
Reference Type	Shunt
Output Type	Fixed
Voltage - Output (Min/Fixed)	1.235V
Current - Output	20 mA
Tolerance	±1%
Noise - 10Hz to 10kHz	60µVrms
Current - Cathode	20 µA
Operating Temperature	-40°C ~ 85°C (TA)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Temperature Coefficient	80ppm/°C Typical

Substitute Part Grouping Explanation

Substitution for the LM285D-1.2 is determined by strict electrical and mechanical compatibility criteria. All substitute parts must maintain the following core parameters:

Fixed output voltage of 1.235V
±1% tolerance specification
20 mA maximum output current capability
8-SOIC surface mount package with 0.154" (3.90mm) width
Operating temperature range of -40°C to 85°C
60µVrms noise specification (10Hz to 10kHz)

Substitute parts are grouped into two categories: Direct Manufacturer Substitutes (functionally equivalent with identical electrical specifications) and Similar Manufacturer Parts (equivalent electrical performance with minor parameter variations within acceptable engineering tolerances). Temperature coefficient variations and cathode current differences do not preclude substitution when all primary electrical and mechanical parameters align.

Parameter Comparison

Part Number	Manufacturer	Product Status	Voltage Output	Tolerance	Temp Coeff	Cathode Current	Package	RoHS Status
LM285D-1.2	onsemi	Obsolete	1.235V	±1%	80ppm/°C	20 µA	8-SOIC	Non-compliant
LM285D-1.2G	onsemi	Active	1.235V	±1%	80ppm/°C	20 µA	8-SOIC	ROHS3 Compliant
LM285BYMX-1.2/NOPB	Texas Instruments	Active	1.235V	±1%	50ppm/°C	10 µA	8-SOIC	ROHS3 Compliant
LM285D-1-2	Texas Instruments	Last Time Buy	1.235V	±1%	20ppm/°C	10 µA	8-SOIC	ROHS3 Compliant
LM285M-1.2/NOPB	Texas Instruments	Active	1.235V	±1%	150ppm/°C	10 µA	8-SOIC	ROHS3 Compliant
LM285MX-1.2/NOPB	Texas Instruments	Active	1.235V	±1%	150ppm/°C	10 µA	8-SOIC	ROHS3 Compliant
LM285BXM-1.2/NOPB	National Semiconductor	Active	1.235V	±1%	30ppm/°C	10 µA	8-SOIC	Not specified
LM285BXMX-1.2/NOPB	Texas Instruments	Active	1.235V	±1%	30ppm/°C	10 µA	8-SOIC	ROHS3 Compliant
LM285BYM-1.2/NOPB	Texas Instruments	Active	1.235V	±1%	50ppm/°C	10 µA	8-SOIC	ROHS3 Compliant
LM285DG4-1-2	Texas Instruments	Obsolete	1.235V	±1%	20ppm/°C	10 µA	8-SOIC	ROHS3 Compliant
LM285DR-1-2	Texas Instruments	Last Time Buy	1.235V	±1%	20ppm/°C	10 µA	8-SOIC	ROHS3 Compliant

Engineering Selection Recommendations

For new designs and production continuity, LM285D-1.2G (onsemi) is the primary direct substitute, offering identical electrical specifications with active product status and ROHS3 compliance. This part maintains the original 80ppm/°C temperature coefficient and 20 µA cathode current, ensuring drop-in compatibility.

For applications where improved temperature stability is beneficial, LM285D-1-2 (Texas Instruments) provides superior performance with 20ppm/°C temperature coefficient, though it carries Last Time Buy status. This part is suitable for designs requiring tighter thermal performance within the -40°C to 85°C operating range.

Active production alternatives include LM285BXMX-1.2/NOPB and LM285BYM-1.2/NOPB (Texas Instruments), both with ROHS3 compliance and extended availability. These parts feature reduced cathode current (10 µA) and improved temperature coefficients (30ppm/°C and 50ppm/°C respectively), making them suitable for low-power applications.

All substitute parts maintain the critical 1.235V fixed output, ±1% tolerance, and 8-SOIC package form factor. Selection should prioritize parts with Active product status for long-term supply assurance. ROHS3 compliance is standard across all active alternatives, supporting modern manufacturing and environmental requirements.

Frequently Asked Questions (FAQ)

Q: Can LM285D-1.2G directly replace LM285D-1.2 in existing designs?

A: Yes. LM285D-1.2G is a direct substitute with identical electrical specifications, including 1.235V output, ±1% tolerance, 80ppm/°C temperature coefficient, and 8-SOIC package. The primary difference is product status (Active vs. Obsolete) and RoHS compliance upgrade.

Q: What is the significance of temperature coefficient differences among substitute parts?

A: Temperature coefficient indicates output voltage drift over the -40°C to 85°C operating range. Lower values (20ppm/°C) provide better thermal stability, while higher values (150ppm/°C) result in greater voltage variation across temperature extremes. Selection depends on application precision requirements.

Q: Are all substitute parts available in the same package?

A: Yes. All listed substitute parts use the 8-SOIC (0.154", 3.90mm Width) surface mount package, ensuring mechanical and electrical compatibility without PCB redesign.

Q: What is the difference between packaging types (Tube, Tape & Reel, Cut Tape)?

A: Packaging type affects handling and assembly processes. Tube packaging suits lower-volume applications, while Tape & Reel and Cut Tape & Digi-Reel formats support automated assembly lines. Electrical performance is identical across packaging variants.

Q: Why do some parts show 10 µA cathode current instead of 20 µA?

A: Cathode current represents the minimum operating current through the reference. Lower values (10 µA) indicate improved efficiency and reduced power consumption, beneficial for battery-powered or low-power applications. Both specifications maintain the 1.235V output and ±1% tolerance.

Q: Which substitute part offers the best long-term availability?

A: Parts with Active product status (LM285D-1.2G, LM285BXMX-1.2/NOPB, LM285BYM-1.2/NOPB, LM285M-1.2/NOPB, LM285MX-1.2/NOPB) provide the longest supply assurance. LM285D-1.2G from onsemi is the closest functional equivalent to the original part.

Q: Is RoHS3 compliance required for my application?

A: RoHS3 compliance is mandatory for products sold in the European Union and increasingly required by major OEMs globally. All active substitute parts listed meet ROHS3 standards, while the original LM285D-1.2 is non-compliant.

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