LM385BD-1.2 Equivalent & Substitute Parts

Part Overview

The LM385BD-1.2 is a shunt voltage reference IC manufactured by onsemi, delivering a fixed 1.235V output with ±1% tolerance. This 8-SOIC surface mount device is classified as a Power Management (PMIC) component and is currently listed as obsolete. The part's discontinuation necessitates identification of functionally equivalent alternatives that maintain electrical and mechanical compatibility for new designs or production continuity.

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	0°C ~ 70°C (TA)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution eligibility for the LM385BD-1.2 is determined by strict alignment of the following critical parameters:

Mandatory Matching Parameters:

Reference Type: Shunt
Output Type: Fixed
Voltage - Output: 1.235V
Current - Output: 20 mA
Tolerance: ±1%
Noise - 10Hz to 10kHz: 60µVrms
Package / Case: 8-SOIC (0.154", 3.90mm Width)
Mounting Type: Surface Mount

Allowable Variations:

Temperature Coefficient: May vary (20ppm/°C to 80ppm/°C)
Current - Cathode: May vary (10 µA to 20 µA)
Operating Temperature Range: May be extended (e.g., -40°C ~ 85°C)
Product Status: Active, Last Time Buy, or Obsolete
RoHS Compliance: May differ
Packaging Format: Tube, Tape & Reel, Bulk, or Cut Tape

Substitutes are classified as Direct (identical base part number with different packaging/compliance) or Similar (different base part number but equivalent electrical specifications).

Parameter Comparison

Part Number	Manufacturer	Voltage Output	Current Output	Tolerance	Temp Coeff	Cathode Current	Operating Temp	Package	Product Status	RoHS Status
LM385BD-1.2	onsemi	1.235V	20 mA	±1%	80ppm/°C	20 µA	0°C ~ 70°C	8-SOIC	Obsolete	RoHS non-compliant
LM385BD-1.2G	onsemi	1.235V	20 mA	±1%	80ppm/°C	20 µA	0°C ~ 70°C	8-SOIC	Active	ROHS3 Compliant
LM385BD-1-2	Texas Instruments	1.235V	20 mA	±1%	20ppm/°C	15 µA	0°C ~ 70°C	8-SOIC	Obsolete	ROHS3 Compliant
LM285BXM-1.2/NOPB	National Semiconductor	1.235V	20 mA	±1%	30ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active	Not specified
LM285BXMX-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	30ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active	ROHS3 Compliant
LM285BYM-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	50ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active	ROHS3 Compliant
LM285BYMX-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	50ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active	ROHS3 Compliant
LM285D-1-2	Texas Instruments	1.235V	20 mA	±1%	20ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Last Time Buy	ROHS3 Compliant
LM285DG4-1-2	Texas Instruments	1.235V	20 mA	±1%	20ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Obsolete	ROHS3 Compliant
LM285DR-1-2	Texas Instruments	1.235V	20 mA	±1%	20ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Last Time Buy	ROHS3 Compliant
LM285DRE4-1-2	Texas Instruments	1.235V	20 mA	±1%	20ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Obsolete	ROHS3 Compliant

Engineering Selection Recommendations

Direct Replacement (Highest Compatibility): LM385BD-1.2G is the primary direct substitute. Manufactured by onsemi with identical electrical specifications, this part maintains the same 1.235V output, ±1% tolerance, and 8-SOIC package. The key advantage is its Active product status and ROHS3 compliance, addressing the obsolescence and regulatory limitations of the original LM385BD-1.2.

Alternative Substitutes (Functional Equivalence): Texas Instruments LM385BD-1-2 provides direct electrical compatibility with ROHS3 compliance, though it carries Obsolete status. For applications requiring extended operating temperature range (-40°C ~ 85°C), the LM285 series variants (LM285BXMX-1.2/NOPB, LM285BYM-1.2/NOPB, LM285BYMX-1.2/NOPB, LM285D-1-2, LM285DR-1-2) deliver identical 1.235V output and ±1% tolerance with Active product status. These parts feature lower cathode current (10 µA vs. 20 µA) and improved temperature coefficients, beneficial for precision applications.

Compliance Considerations: For new designs or production requiring regulatory compliance, select only parts with ROHS3 Compliant status. LM385BD-1.2G and all LM285 variants meet this requirement. The original LM385BD-1.2 is RoHS non-compliant and unsuitable for applications subject to RoHS directives.

Inventory and Availability: LM285DR-1-2 (35,300 pcs) and LM285DRE4-1-2 (21,900 pcs) offer the highest stock levels. LM385BD-1.2G (5,225 pcs) and LM285BYMX-1.2/NOPB (5,200 pcs) provide substantial availability with Active status.

Frequently Asked Questions (FAQ)

Q: Can LM385BD-1.2G directly replace LM385BD-1.2 without circuit modification? A: Yes. LM385BD-1.2G is electrically and mechanically identical to LM385BD-1.2, differing only in packaging format (Tube) and RoHS compliance status. No circuit changes are required.

Q: What is the difference between LM385 and LM285 series parts? A: Both series deliver 1.235V fixed output with ±1% tolerance in 8-SOIC packages. The LM285 series offers extended operating temperature range (-40°C ~ 85°C vs. 0°C ~ 70°C), lower cathode current (10 µA vs. 20 µA), and improved temperature coefficients. Electrical substitution is valid when temperature range requirements are met.

Q: Are there differences in temperature coefficient between substitute parts? A: Yes. The original LM385BD-1.2 specifies 80ppm/°C. Substitutes range from 20ppm/°C (LM285 variants) to 80ppm/°C (LM385BD-1.2G). Lower temperature coefficients provide better stability across temperature variations. Selection depends on application precision requirements.

Q: Does cathode current variation affect circuit design? A: Cathode current ranges from 10 µA to 20 µA across substitutes. This parameter affects bias network design and power consumption. Verify that existing bias resistor networks accommodate the selected part's cathode current specification.

Q: Which substitute is recommended for new production designs? A: LM385BD-1.2G is the preferred choice for new designs, offering Active product status, ROHS3 compliance, and direct compatibility. For applications requiring extended temperature range, LM285BXMX-1.2/NOPB or LM285BYMX-1.2/NOPB provide superior performance with Active status and full compliance.

Q: Are packaging format differences (Tube, Tape & Reel, Bulk) electrically significant? A: No. Packaging format affects handling, storage, and assembly processes but does not alter electrical performance. Select based on production volume and assembly equipment compatibility.

Q: What is the significance of "Last Time Buy" product status? A: Last Time Buy indicates the manufacturer will discontinue the part after a final production run. Parts with this status have defined end-of-life dates. For long-term production, select parts with Active status.

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