LM385D-1.2R2 Equivalent & Substitute Parts

Part Overview

The LM385D-1.2R2 is a shunt voltage reference IC manufactured by onsemi, delivering a fixed 1.235V output with -2.4%, +2.01% tolerance. This 8-SOIC surface mount device operates across 0°C to 70°C and is classified as obsolete. Due to its obsolete status and limited availability (2204 pcs), identifying active equivalent parts is essential for new designs and production continuity.

Key Parameters

Parameter	Value
Reference Type	Shunt
Output Type	Fixed
Voltage - Output (Min/Fixed)	1.235V
Current - Output	20 mA
Tolerance	-2.4%, +2.01%
Temperature Coefficient	80ppm/°C Typical
Noise - 10Hz to 10kHz	60µVrms
Current - Cathode	20 µA
Operating Temperature	0°C ~ 70°C (TA)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict parameter matching across five critical dimensions:

1. Electrical Compatibility

Fixed output voltage: 1.235V (all candidates match)
Output current: 20 mA (all candidates match)
Noise specification: 60µVrms at 10Hz to 10kHz (all candidates match)
Package type: 8-SOIC form factor (all candidates match)

2. Tolerance & Stability

Tolerance range must encompass or be tighter than -2.4%, +2.01%
Temperature coefficient affects long-term stability across operating range

3. Operating Temperature Range

Original part: 0°C ~ 70°C
Candidates with extended range (-40°C ~ 85°C) provide broader application capability

4. Cathode Current Requirements

Original part: 20 µA
Candidates range from 10 µA to 20 µA (lower values indicate improved efficiency)

5. Product Status & Compliance

Active status ensures ongoing availability
RoHS3 compliance required for new designs
Packaging format (Tape & Reel, Bulk, Tube) affects procurement logistics

Parameter Comparison

Part Number	Manufacturer	Voltage Output	Tolerance	Temp Coeff	Cathode Current	Operating Temp	Product Status	RoHS Status	Packaging
LM385D-1.2R2	onsemi	1.235V	-2.4%, +2.01%	80ppm/°C	20 µA	0°C ~ 70°C	Obsolete	Non-compliant	Bulk
LM385D-1.2R2G	onsemi	1.235V	-2.4%, +2.01%	80ppm/°C	20 µA	0°C ~ 70°C	Active	RoHS3 Compliant	Tape & Reel
LM385DR-1-2	Texas Instruments	1.235V	±2%	20ppm/°C	15 µA	0°C ~ 70°C	Last Time Buy	RoHS3 Compliant	Tape & Reel
LM285BXM-1.2/NOPB	National Semiconductor	1.235V	±1%	30ppm/°C	10 µA	-40°C ~ 85°C	Active	Not specified	Bulk
LM285BXMX-1.2/NOPB	Texas Instruments	1.235V	±1%	30ppm/°C	10 µA	-40°C ~ 85°C	Active	RoHS3 Compliant	Tape & Reel
LM285BYM-1.2/NOPB	Texas Instruments	1.235V	±1%	50ppm/°C	10 µA	-40°C ~ 85°C	Active	RoHS3 Compliant	Tube
LM285BYMX-1.2/NOPB	Texas Instruments	1.235V	±1%	50ppm/°C	10 µA	-40°C ~ 85°C	Active	RoHS3 Compliant	Tape & Reel
LM285D-1-2	Texas Instruments	1.235V	±1%	20ppm/°C	10 µA	-40°C ~ 85°C	Last Time Buy	RoHS3 Compliant	Tube
LM285DG4-1-2	Texas Instruments	1.235V	±1%	20ppm/°C	10 µA	-40°C ~ 85°C	Obsolete	RoHS3 Compliant	Tube
LM285DR-1-2	Texas Instruments	1.235V	±1%	20ppm/°C	10 µA	-40°C ~ 85°C	Last Time Buy	RoHS3 Compliant	Cut Tape & Digi-Reel
LM285DRE4-1-2	Texas Instruments	1.235V	±1%	20ppm/°C	10 µA	-40°C ~ 85°C	Obsolete	RoHS3 Compliant	Tape & Reel

Engineering Selection Recommendations

Primary Recommendation: LM385D-1.2R2G This onsemi part maintains identical electrical specifications to the original LM385D-1.2R2 while offering active product status and RoHS3 compliance. The only difference is packaging format (Tape & Reel vs. Bulk), making it the direct replacement for existing designs without circuit modification.

Secondary Recommendation: LM285BXMX-1.2/NOPB or LM285BYMX-1.2/NOPB Texas Instruments LM285 series parts provide tighter tolerance (±1% vs. -2.4%, +2.01%), lower cathode current (10 µA vs. 20 µA), and extended operating temperature range (-40°C ~ 85°C). Both are active products with RoHS3 compliance. The BXMX variant offers 30ppm/°C temperature coefficient; BYMX offers 50ppm/°C. Both are electrically compatible in 8-SOIC packaging.

Alternative for Extended Temperature Range: LM285DR-1-2 This Texas Instruments part provides the broadest operating temperature range (-40°C ~ 85°C) with ±1% tolerance and 20ppm/°C temperature coefficient. Last Time Buy status indicates limited future availability; procurement should prioritize this part if extended temperature operation is required.

Avoid: LM285DG4-1-2 and LM285DRE4-1-2 Both are obsolete, limiting their suitability for new production despite RoHS3 compliance.

Frequently Asked Questions (FAQ)

Q: Can LM385D-1.2R2G directly replace LM385D-1.2R2 without circuit changes? A: Yes. Both parts are electrically identical with matching voltage output (1.235V), tolerance (-2.4%, +2.01%), temperature coefficient (80ppm/°C), and operating range (0°C ~ 70°C). The only difference is packaging format (Tape & Reel vs. Bulk), which does not affect circuit performance.

Q: What is the advantage of LM285 series parts over LM385 equivalents? A: LM285 parts offer tighter tolerance (±1%), lower cathode current (10 µA vs. 20 µA for improved efficiency), and extended operating temperature range (-40°C ~ 85°C vs. 0°C ~ 70°C). These improvements come at the cost of higher temperature coefficient (20-50ppm/°C vs. 80ppm/°C for the original).

Q: Are all substitute parts RoHS3 compliant? A: No. LM285BXM-1.2/NOPB (National Semiconductor) does not specify RoHS status. All Texas Instruments and onsemi parts listed are RoHS3 compliant. For new designs subject to RoHS requirements, select only parts explicitly marked RoHS3 Compliant.

Q: What is the difference between packaging formats (Tape & Reel, Bulk, Tube)? A: Tape & Reel and Cut Tape formats are optimized for automated assembly lines. Bulk and Tube formats are suitable for manual assembly or lower-volume applications. Electrical performance is identical; packaging affects procurement and assembly logistics only.

Q: Why do some parts show "Last Time Buy" status? A: Last Time Buy indicates the manufacturer has announced end-of-life production. These parts remain available but in limited quantities. For long-term production, prioritize Active status parts such as LM385D-1.2R2G or LM285BXMX-1.2/NOPB.

Q: Can I use LM285DR-1-2 in applications requiring 0°C ~ 70°C operation? A: Yes. LM285DR-1-2 operates across -40°C ~ 85°C, which encompasses the 0°C ~ 70°C range. However, its Last Time Buy status suggests limited future availability; confirm long-term supply before committing to production designs.

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