LM385BDR-1-2 Equivalent & Substitute Parts

Part Overview

The LM385BDR-1-2 is a shunt voltage reference IC manufactured by Texas Instruments, delivering a fixed 1.235V output with ±1% tolerance. Classified as a Power Management (PMIC) component, this 8-SOIC surface mount device operates across the 0°C to 70°C temperature range and is currently in Last Time Buy status. The part is ROHS3 compliant with unlimited moisture sensitivity level (MSL 1). Due to its Last Time Buy status, identifying equivalent substitute parts with compatible electrical and mechanical specifications is essential for design continuity and long-term supply chain planning.

Key Parameters

Parameter	Value
Reference Type	Shunt
Output Type	Fixed
Voltage - Output (Min/Fixed)	1.235V
Current - Output	20 mA
Tolerance	±1%
Temperature Coefficient	20ppm/°C Typical
Noise - 10Hz to 10kHz	60µVrms
Current - Cathode	15 µA
Operating Temperature	0°C ~ 70°C (TA)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the LM385BDR-1-2 is determined by strict adherence to the following critical parameters:

Mandatory Matching Parameters:

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

Allowable Variation Parameters:

Temperature Coefficient: May vary (20ppm/°C to 150ppm/°C acceptable for substitution)
Current - Cathode: May vary (10 µA to 15 µA acceptable for substitution)
Operating Temperature: May extend beyond 0°C ~ 70°C range (-40°C ~ 85°C acceptable)
Packaging Format: Cut Tape (CT), Tape & Reel (TR), Tube, or Bulk acceptable
Manufacturer: Texas Instruments or National Semiconductor acceptable

Substitute parts are grouped by operating temperature range and temperature coefficient characteristics, as these parameters define performance boundaries while maintaining functional equivalence.

Parameter Comparison

Part Number	Manufacturer	Voltage Output	Current Output	Tolerance	Temp Coeff	Cathode Current	Operating Temp	Package	Product Status
LM385BDR-1-2	Texas Instruments	1.235V	20 mA	±1%	20ppm/°C	15 µA	0°C ~ 70°C	8-SOIC	Last Time Buy
LM285BXM-1.2/NOPB	National Semiconductor	1.235V	20 mA	±1%	30ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active
LM285BXMX-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	30ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active
LM285BYM-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	50ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active
LM285BYMX-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	50ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active
LM285M-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	150ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active
LM285MX-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	150ppm/°C	10 µA	-40°C ~ 85°C	8-SOIC	Active
LM385BM-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	150ppm/°C	15 µA	0°C ~ 70°C	8-SOIC	Active
LM385BMX-1.2/NOPB	Texas Instruments	1.235V	20 mA	±1%	150ppm/°C	15 µA	0°C ~ 70°C	8-SOIC	Active
LM385BXM-1.2/NOPB	National Semiconductor	1.235V	20 mA	±1%	30ppm/°C	15 µA	0°C ~ 70°C	8-SOIC	Active
LM385BXMX-1.2/NOPB	National Semiconductor	1.235V	20 mA	±1%	30ppm/°C	15 µA	0°C ~ 70°C	8-SOIC	Active

Engineering Selection Recommendations

All listed substitute parts maintain Active product status, ensuring ongoing availability and manufacturer support. Selection between substitute options depends on application-specific requirements:

For applications requiring identical operating temperature range (0°C ~ 70°C) and cathode current (15 µA): LM385BM-1.2/NOPB and LM385BMX-1.2/NOPB provide direct functional equivalence with 150ppm/°C temperature coefficient. LM385BXM-1.2/NOPB and LM385BXMX-1.2/NOPB offer improved temperature stability at 30ppm/°C while maintaining the same operating range and cathode current specifications.

For applications tolerating extended operating temperature range (-40°C ~ 85°C): LM285BXM-1.2/NOPB and LM285BXMX-1.2/NOPB deliver superior temperature stability (30ppm/°C) with reduced cathode current (10 µA). LM285BYM-1.2/NOPB and LM285BYMX-1.2/NOPB provide moderate temperature coefficient (50ppm/°C) with extended temperature coverage. LM285M-1.2/NOPB and LM285MX-1.2/NOPB offer the widest temperature range with higher temperature coefficient (150ppm/°C).

All substitute parts are ROHS3 compliant with MSL 1 rating, matching the original part's environmental and regulatory compliance profile. Packaging format selection (Cut Tape, Tape & Reel, Tube, or Bulk) should align with assembly process requirements and inventory management practices.

Frequently Asked Questions (FAQ)

Q: Can LM285 series parts directly replace LM385BDR-1-2? A: Yes. LM285 series parts maintain identical voltage output (1.235V), current output (20 mA), tolerance (±1%), and 8-SOIC package specifications. The primary differences are extended operating temperature range (-40°C ~ 85°C versus 0°C ~ 70°C) and reduced cathode current (10 µA versus 15 µA), both of which are acceptable variations for substitution.

Q: What is the significance of temperature coefficient variation? A: Temperature coefficient (measured in ppm/°C) defines output voltage drift across the operating temperature range. The LM385BDR-1-2 specifies 20ppm/°C. Substitute parts range from 30ppm/°C to 150ppm/°C. Lower coefficients provide better voltage stability across temperature extremes. Selection depends on application sensitivity to voltage drift; applications with tight voltage regulation requirements should prioritize lower temperature coefficients.

Q: Are National Semiconductor and Texas Instruments parts interchangeable? A: Yes, for the specified parameters. Both manufacturers produce functionally equivalent parts with identical voltage output, current output, tolerance, and package specifications. National Semiconductor parts (LM285BXM-1.2/NOPB, LM285BXMX-1.2/NOPB, LM385BXM-1.2/NOPB, LM385BXMX-1.2/NOPB) are electrically compatible with Texas Instruments equivalents.

Q: Does packaging format affect electrical performance? A: No. Cut Tape (CT), Tape & Reel (TR), Tube, and Bulk packaging formats contain identical die and electrical specifications. Packaging selection is determined by assembly process requirements, volume quantities, and inventory handling procedures, not electrical performance.

Q: Why do some substitutes have lower cathode current (10 µA versus 15 µA)? A: Cathode current represents the minimum operating current required to maintain regulation. Lower cathode current (10 µA) indicates improved efficiency and reduced power consumption. This is an acceptable variation for substitution, as it represents improved performance rather than degradation.

Q: Can I use parts with extended operating temperature range in applications limited to 0°C ~ 70°C? A: Yes. Parts rated for -40°C ~ 85°C operation are fully functional within the 0°C ~ 70°C range. Extended temperature rating provides design flexibility for future applications or thermal margin without compromising performance in the specified operating window.

Q: What is the impact of different packaging formats on lead times? A: Packaging format availability varies by distributor and manufacturer inventory levels. Cut Tape and Tape & Reel formats typically support automated assembly processes. Tube and Bulk formats may have different lead times and minimum order quantities. Verify current inventory status with your component supplier for specific packaging requirements.

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