LM385Z-1.2RA Equivalent & Substitute Parts

Part Overview

The LM385Z-1.2RA is a shunt voltage reference IC manufactured by onsemi, providing a fixed 1.235V output with -2.4%, +2.01% tolerance. This through-hole TO-92-3 package component operates across 0°C to 70°C and delivers 20 mA output current with 80 ppm/°C temperature coefficient. The part is classified as obsolete, necessitating identification of active equivalent and substitute components for new designs and ongoing production requirements.

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	80 ppm/°C Typical
Noise - 10Hz to 10kHz	60 µVrms
Current - Cathode	20 µA
Operating Temperature	0°C ~ 70°C (TA)
Mounting Type	Through Hole
Package / Case	TO-226-3, TO-92-3 (TO-226AA) Formed Leads
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitute parts are classified into three categories based on electrical and mechanical parameter alignment:

Direct Manufacturer Equivalents maintain identical output voltage (1.235V), output current (20 mA), reference type (shunt), output type (fixed), package (TO-92-3), and mounting type (through hole). These parts differ primarily in packaging format (tape & reel, cut tape, or bulk) and product status (active vs. obsolete). Tolerance and temperature coefficient variations within acceptable ranges are noted.

Parametric Equivalents share all critical electrical specifications with the main part but may originate from different manufacturers. These components meet the same functional requirements for voltage reference applications.

Similar Parts maintain the same output voltage, current rating, package, and mounting type but feature improved tolerance specifications (±1% vs. -2.4%, +2.01%) and lower temperature coefficients. These components provide enhanced performance characteristics while maintaining mechanical and electrical compatibility for the reference voltage function.

The key parameters determining substitution eligibility are: output voltage (1.235V), output current (20 mA), reference type (shunt), package (TO-92-3), and mounting type (through hole).

Parameter Comparison

Part Number	Manufacturer	Voltage Output	Current Output	Tolerance	Temp Coeff	Cathode Current	Operating Temp	Packaging	Product Status	RoHS Status
LM385Z-1.2RA	onsemi	1.235V	20 mA	-2.4%, +2.01%	80 ppm/°C	20 µA	0°C ~ 70°C	TO-92-3	Obsolete	RoHS non-compliant
LM385Z-1.2RAG	onsemi	1.235V	20 mA	-2.4%, +2.01%	80 ppm/°C	20 µA	0°C ~ 70°C	TO-92-3	Active	ROHS3 Compliant
LM385Z-1.2RPG	onsemi	1.235V	20 mA	-2.4%, +2.01%	80 ppm/°C	20 µA	0°C ~ 70°C	TO-92-3	Active	ROHS3 Compliant
LM385LPR-1-2	Texas Instruments	1.235V	20 mA	±2%	20 ppm/°C	15 µA	0°C ~ 70°C	TO-92-3	Active	ROHS3 Compliant
LM385LPRE3-1-2	Texas Instruments	1.235V	20 mA	±2%	20 ppm/°C	15 µA	0°C ~ 70°C	TO-92-3	Active	ROHS3 Compliant
LM385Z-1.2/LFT3	Texas Instruments	1.235V	20 mA	-2.43%, +2.02%	150 ppm/°C	15 µA	0°C ~ 70°C	TO-92-3	Active	ROHS3 Compliant
LM385Z-1.2/LFT4	National Semiconductor	1.235V	20 mA	-2.43%, +2.02%	150 ppm/°C	15 µA	0°C ~ 70°C	TO-92-3	Active	Not specified
LM285BXZ-1.2/LFT4	National Semiconductor	1.235V	20 mA	±1%	30 ppm/°C	10 µA	-40°C ~ 85°C	TO-92-3	Active	Not specified
LM285LPRE3-1-2	Texas Instruments	1.235V	20 mA	±1%	20 ppm/°C	10 µA	-40°C ~ 85°C	TO-92-3	Active	ROHS3 Compliant
LM285Z-1.2#TRPBF	Analog Devices Inc.	1.235V	20 mA	±1%	20 ppm/°C	10 µA	-40°C ~ 85°C	TO-92-3	Active	ROHS3 Compliant
LM385BLPR-1-2	Texas Instruments	1.235V	20 mA	±1%	20 ppm/°C	15 µA	0°C ~ 70°C	TO-92-3	Active	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Obsolete to Active): LM385Z-1.2RAG and LM385Z-1.2RPG are the primary direct substitutes, maintaining identical electrical specifications while offering active product status and ROHS3 compliance. These components are sourced from onsemi and differ only in packaging format (tape & reel and cut tape respectively).

For Improved Performance with Extended Temperature Range: LM285LPRE3-1-2 (Texas Instruments) and LM285Z-1.2#TRPBF (Analog Devices Inc.) provide ±1% tolerance and 20 ppm/°C temperature coefficient with extended operating range (-40°C to 85°C). These components are ROHS3 compliant and suitable for applications requiring tighter voltage regulation and broader temperature operation.

For Standard Temperature Range Applications: LM385LPR-1-2 and LM385LPRE3-1-2 (Texas Instruments) maintain the 0°C to 70°C operating range with improved ±2% tolerance and 20 ppm/°C temperature coefficient. Both are ROHS3 compliant and available in active product status.

Compliance Considerations: The original LM385Z-1.2RA is RoHS non-compliant. All recommended active substitutes (onsemi LM385Z-1.2RAG/RPG and Texas Instruments LM385LPR-1-2/LPRE3-1-2) are ROHS3 compliant, meeting current regulatory requirements for new designs and production.

Frequently Asked Questions (FAQ)

Q: Can LM385Z-1.2RAG directly replace LM385Z-1.2RA without circuit modification? A: Yes. LM385Z-1.2RAG maintains identical electrical specifications (1.235V output, 20 mA current, -2.4%, +2.01% tolerance, 80 ppm/°C temperature coefficient) and TO-92-3 package. The difference is packaging format (tape & reel vs. loose) and product status (active vs. obsolete). No circuit changes are required.

Q: What is the difference between LM385Z-1.2RAG and LM385Z-1.2RPG? A: Both parts are onsemi LM385 variants with identical electrical specifications. LM385Z-1.2RAG is supplied in tape & reel packaging, while LM385Z-1.2RPG is supplied in cut tape format. Selection depends on procurement and assembly requirements.

Q: Why would I choose LM285LPRE3-1-2 over LM385LPR-1-2? A: LM285LPRE3-1-2 offers superior specifications: ±1% tolerance (vs. ±2%), 20 ppm/°C temperature coefficient (vs. 20 ppm/°C, equivalent), and extended operating temperature range (-40°C to 85°C vs. 0°C to 70°C). Selection depends on application requirements for voltage accuracy and temperature performance.

Q: Are all substitute parts RoHS compliant? A: The original LM385Z-1.2RA is RoHS non-compliant. All recommended active substitutes from onsemi and Texas Instruments are ROHS3 compliant. Analog Devices LM285Z-1.2#TRPBF is also ROHS3 compliant. Compliance status should be verified for specific procurement requirements.

Q: Can I use LM385BLPR-1-2 as a substitute? A: LM385BLPR-1-2 is compatible mechanically and functionally, featuring the same 1.235V output and TO-92-3 package. However, it offers ±1% tolerance (tighter than the original -2.4%, +2.01%) and operates across 0°C to 70°C. It is ROHS3 compliant and active status, making it suitable for applications where improved voltage accuracy is beneficial.

Q: What is the significance of the temperature coefficient difference between parts? A: Temperature coefficient indicates voltage drift with temperature change. The original LM385Z-1.2RA has 80 ppm/°C, while most substitutes offer 20 ppm/°C or lower. Lower values indicate better voltage stability across temperature variations, beneficial for precision applications. Selection should match application temperature stability requirements.

Q: Are there inventory considerations for these substitutes? A: Inventory levels vary significantly. LM385Z-1.2/LFT4 has the highest inventory (69,797 pcs), while LM285Z-1.2#TRPBF has lower availability (896 pcs). Procurement strategy should account for supply availability and lead times for production planning.

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