LM385PSR-1-2 Equivalent & Substitute Parts

Part Overview

The LM385PSR-1-2 is a shunt voltage reference IC manufactured by Texas Instruments, delivering a fixed 1.235V output with ±2% tolerance. Classified as a Power Management (PMIC) component, this device operates in the 0°C to 70°C temperature range and is packaged in an 8-SO surface mount configuration. The product status is obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Reference Type	Shunt
Output Type	Fixed
Voltage - Output (Min/Fixed)	1.235V
Current - Output	20 mA
Tolerance	±2%
Noise - 10Hz to 10kHz	60µVrms
Current - Cathode	15 µA
Operating Temperature	0°C ~ 70°C (TA)
Mounting Type	Surface Mount
Package / Case	8-SOIC (0.209", 5.30mm Width)

Substitute Part Grouping Explanation

Substitution for the LM385PSR-1-2 is determined by the following critical parameters:

Reference Type: Shunt
Output Voltage: 1.235V (fixed)
Output Current: 20 mA
Noise Performance: 60µVrms (10Hz to 10kHz)
Mounting Type: Surface Mount
Package Compatibility: 8-SOIC form factor

Substitute parts must maintain identical output voltage, current rating, and noise specifications. Tolerance variations (±2% vs. ±1%), temperature coefficient differences, and operating temperature ranges are secondary considerations that depend on application requirements. Package physical dimensions and supplier packaging formats (Bulk, Tube, Tape & Reel) do not affect electrical compatibility.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Tolerance	Current - Output	Noise (10Hz-10kHz)	Current - Cathode	Operating Temp	Product Status	Package
LM385PSR-1-2	Texas Instruments	1.235V	±2%	20 mA	60µVrms	15 µA	0°C ~ 70°C	Obsolete	8-SOIC (5.30mm)
LM285BXM-1.2/NOPB	National Semiconductor	1.235V	±1%	20 mA	60µVrms	10 µA	-40°C ~ 85°C	Active	8-SOIC (3.90mm)
LM285BXMX-1.2/NOPB	Texas Instruments	1.235V	±1%	20 mA	60µVrms	10 µA	-40°C ~ 85°C	Active	8-SOIC (3.90mm)
LM285BYM-1.2/NOPB	Texas Instruments	1.235V	±1%	20 mA	60µVrms	10 µA	-40°C ~ 85°C	Active	8-SOIC (3.90mm)
LM285BYMX-1.2/NOPB	Texas Instruments	1.235V	±1%	20 mA	60µVrms	10 µA	-40°C ~ 85°C	Active	8-SOIC (3.90mm)
LM285M-1.2/NOPB	Texas Instruments	1.235V	±1%	20 mA	60µVrms	10 µA	-40°C ~ 85°C	Active	8-SOIC (3.90mm)
LM285MX-1.2/NOPB	Texas Instruments	1.235V	±1%	20 mA	60µVrms	10 µA	-40°C ~ 85°C	Active	8-SOIC (3.90mm)
LM385BXM-1.2/NOPB	National Semiconductor	1.235V	±1%	20 mA	60µVrms	15 µA	0°C ~ 70°C	Active	8-SOIC (3.90mm)
LM385BXMX-1.2/NOPB	National Semiconductor	1.235V	±1%	20 mA	60µVrms	15 µA	0°C ~ 70°C	Active	8-SOIC (3.90mm)
LM385BYM-1.2/NOPB	Texas Instruments	1.235V	±1%	20 mA	60µVrms	15 µA	0°C ~ 70°C	Active	8-SOIC (3.90mm)
LM385BYMX-1.2/NOPB	Texas Instruments	1.235V	±1%	20 mA	60µVrms	15 µA	0°C ~ 70°C	Active	8-SOIC (3.90mm)

Engineering Selection Recommendations

All listed substitute parts maintain the core electrical specifications required for direct replacement: 1.235V fixed output, 20 mA output current, and 60µVrms noise performance. The primary distinction between substitutes lies in product status and operating temperature range.

For applications requiring extended temperature operation beyond 0°C to 70°C, the LM285 series (LM285BXM-1.2/NOPB, LM285BXMX-1.2/NOPB, LM285BYM-1.2/NOPB, LM285BYMX-1.2/NOPB, LM285M-1.2/NOPB, LM285MX-1.2/NOPB) provides -40°C to 85°C operation with improved tolerance (±1% vs. ±2%). These parts are all active products with full manufacturer support.

For applications constrained to the original 0°C to 70°C operating range, the LM385 series substitutes (LM385BXM-1.2/NOPB, LM385BXMX-1.2/NOPB, LM385BYM-1.2/NOPB, LM385BYMX-1.2/NOPB) are active alternatives. All substitute parts are ROHS3 compliant and carry REACH Unaffected status where specified.

Frequently Asked Questions (FAQ)

Q: Can LM285 series parts directly replace the LM385PSR-1-2?

A: Yes. Both series deliver identical 1.235V output, 20 mA current, and 60µVrms noise. The LM285 series offers superior tolerance (±1% vs. ±2%) and extended operating temperature (-40°C to 85°C vs. 0°C to 70°C). Physical package dimensions differ slightly (3.90mm vs. 5.30mm width), but both use 8-SOIC form factor suitable for standard surface mount assembly.

Q: What is the difference between LM385BXM and LM385BYM variants?

A: Both maintain identical electrical specifications for the LM385PSR-1-2 replacement. The suffix designates temperature coefficient: BXM specifies 30ppm/°C, while BYM specifies 50ppm/°C. Selection depends on application sensitivity to temperature-induced voltage drift.

Q: Does packaging format (Bulk, Tube, Tape & Reel) affect electrical compatibility?

A: No. Packaging format affects only procurement and handling logistics. Electrical performance and pin configuration remain identical across all packaging options for a given part number.

Q: Are all substitute parts currently available?

A: All listed substitutes carry active product status with manufacturer support. Inventory availability varies by supplier and packaging format, with quantities ranging from 1,305 to 9,302 pieces across different part numbers and packaging options.

Q: Which substitute offers the best tolerance specification?

A: All LM285 and LM385 series substitutes provide ±1% tolerance, superior to the original LM385PSR-1-2 specification of ±2%. This improvement applies uniformly across all substitute options listed.

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