LM285BYZ/NOPB Equivalent & Substitute Parts

Part Overview

The LM285BYZ/NOPB is an adjustable shunt voltage reference IC manufactured by Texas Instruments, designed for precision voltage regulation applications. This TO-92-3 packaged component operates with a fixed output voltage of 1.24V and supports maximum output current of 20 mA. The device maintains ±1% tolerance across its operating temperature range of -40°C to 85°C. As an active product with ROHS3 compliance, the LM285BYZ/NOPB remains in production; however, alternative components may be required for applications demanding higher output voltage ranges, increased current capacity, or extended temperature specifications.

Key Parameters

Parameter	LM285BYZ/NOPB
Manufacturer	Texas Instruments
Reference Type	Shunt
Output Type	Adjustable
Voltage - Output (Min/Fixed)	1.24V
Voltage - Output (Max)	5.3V
Current - Output	20 mA
Tolerance	±1%
Temperature Coefficient	50ppm/°C
Noise - 10Hz to 10kHz	50µVrms
Current - Cathode	45 µA
Operating Temperature	-40°C ~ 85°C
Package / Case	TO-92-3
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the LM285BYZ/NOPB is determined by compatibility across the following critical parameters:

Reference Type & Output Type: Both main and substitute parts must function as adjustable shunt voltage references to maintain circuit functionality.

Package / Case: Physical compatibility requires identical TO-92-3 through-hole packaging to ensure direct board-level replacement without layout modifications.

Tolerance & Compliance: ±1% tolerance specification and ROHS3 compliance must be maintained to meet regulatory and precision requirements.

Electrical Performance: Substitute parts must support the required output voltage range, output current capacity, and operating temperature specifications for the target application. The TL431AIZ qualifies as a substitute due to its adjustable shunt reference architecture, identical TO-92-3 package, matching ±1% tolerance, and ROHS3 compliance. However, the TL431AIZ exhibits higher maximum output voltage (36V vs. 5.3V), increased output current capacity (100 mA vs. 20 mA), extended operating temperature range (-40°C to 105°C vs. -40°C to 85°C), and higher cathode current (700 µA vs. 45 µA).

Parameter Comparison

Parameter	LM285BYZ/NOPB	TL431AIZ	Compatibility Notes
Manufacturer	Texas Instruments	STMicroelectronics	Different manufacturers; both active products
Reference Type	Shunt	Shunt	Identical functional type
Output Type	Adjustable	Adjustable	Identical output configuration
Voltage - Output (Min/Fixed)	1.24V	2.495V	TL431AIZ has higher minimum output voltage
Voltage - Output (Max)	5.3V	36V	TL431AIZ supports extended voltage range
Current - Output	20 mA	100 mA	TL431AIZ provides higher current capacity
Tolerance	±1%	±1%	Identical tolerance specification
Current - Cathode	45 µA	700 µA	TL431AIZ requires higher cathode current
Operating Temperature	-40°C ~ 85°C	-40°C ~ 105°C	TL431AIZ supports extended temperature range
Package / Case	TO-92-3	TO-92-3	Identical package; direct physical replacement
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Both meet regulatory requirements

Engineering Selection Recommendations

LM285BYZ/NOPB Selection: Retain the LM285BYZ/NOPB for applications requiring output voltage limited to 5.3V maximum, output current not exceeding 20 mA, and operating temperatures within -40°C to 85°C. This device is the primary choice when cathode current must remain below 45 µA and lower noise performance (50µVrms at 10Hz to 10kHz) is specified.

TL431AIZ Selection: Use the TL431AIZ as a substitute when applications require higher output voltage capability (up to 36V), increased output current (up to 100 mA), or extended operating temperature range (-40°C to 105°C). The TL431AIZ is suitable for designs where higher cathode current (700 µA) is acceptable and the application does not depend on the specific noise characteristics of the LM285BYZ/NOPB.

Both devices maintain ROHS3 compliance and ±1% tolerance, ensuring regulatory conformance and precision requirements are met across substitution scenarios.

Frequently Asked Questions (FAQ)

Q: Can the TL431AIZ directly replace the LM285BYZ/NOPB in all applications?

A: Direct replacement is possible only when the application circuit can accommodate the TL431AIZ's higher minimum output voltage (2.495V vs. 1.24V), increased cathode current requirement (700 µA vs. 45 µA), and extended voltage range capability (36V vs. 5.3V). Circuit design must be verified to ensure these parameter differences do not affect system performance.

Q: Are the TO-92-3 packages physically identical?

A: Yes. Both the LM285BYZ/NOPB and TL431AIZ use TO-92-3 through-hole packaging with identical pin configuration, enabling direct physical board-level replacement without layout modification.

Q: What is the impact of higher cathode current in the TL431AIZ?

A: The TL431AIZ requires 700 µA cathode current compared to 45 µA for the LM285BYZ/NOPB. This increased current draw affects power supply design and may require circuit modifications to bias networks. Applications with strict power budget constraints should evaluate this parameter carefully.

Q: Do both devices meet the same compliance standards?

A: Yes. Both the LM285BYZ/NOPB and TL431AIZ are ROHS3 compliant and REACH unaffected, meeting identical regulatory requirements for electronic component use.

Q: Which device should be selected for temperature-critical applications?

A: The TL431AIZ supports an extended operating temperature range of -40°C to 105°C, compared to -40°C to 85°C for the LM285BYZ/NOPB. Applications requiring operation above 85°C must use the TL431AIZ.

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