4N28VM Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N28VM is an optoisolator transistor with base output manufactured by onsemi, designed for high-voltage isolation applications requiring 4170Vrms isolation rating. This component features a single-channel configuration in a 6-DIP package and is classified as obsolete. Due to its obsolete status, identifying equivalent and substitute parts is essential for ongoing system maintenance, redesign efforts, and procurement continuity.

Key Parameters

Parameter	Value
Manufacturer Part Number	4N28VM
Manufacturer	onsemi
Category	Optoisolators
Package / Case	6-DIP (0.300", 7.62mm)
Number of Channels	1
Voltage - Isolation	4170Vrms
Output Type	Transistor with Base
Voltage - Output (Max)	30V
Current Transfer Ratio (Min)	10% @ 10mA
Vce Saturation (Max)	500mV
Operating Temperature	-40°C ~ 100°C
Mounting Type	Through Hole
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the 4N28VM is determined by the following critical parameters:

Package compatibility: 6-DIP (0.300", 7.62mm) form factor for direct pin-compatible replacement
Isolation voltage: Minimum 4170Vrms to maintain electrical isolation requirements
Output configuration: Transistor with base output for circuit interface compatibility
Single-channel design: One isolated channel matching the original specification
Current transfer ratio: Minimum 10% @ 10mA for signal transmission capability
Output voltage rating: Maximum 30V or higher to support application voltage levels
Vce saturation: Maximum 500mV for switching performance consistency

Two substitute parts are identified:

Direct Equivalent (4N28M): Identical electrical and mechanical specifications with active product status and improved availability.

Enhanced Substitute (4N28-X001): Higher isolation voltage (5000Vrms), increased output voltage rating (70V), and extended temperature range (-55°C ~ 100°C), suitable for applications requiring enhanced performance margins.

Parameter Comparison

Parameter	4N28VM (Main)	4N28M (Direct)	4N28-X001 (Enhanced)
Manufacturer	onsemi	onsemi	Vishay Semiconductor Opto Division
Package / Case	6-DIP (0.300", 7.62mm)	6-DIP (0.300", 7.62mm)	6-DIP (0.300", 7.62mm)
Number of Channels	1	1	1
Voltage - Isolation	4170Vrms	4170Vrms	5000Vrms
Output Type	Transistor with Base	Transistor with Base	Transistor with Base
Voltage - Output (Max)	30V	30V	70V
Current Transfer Ratio (Min)	10% @ 10mA	10% @ 10mA	10% @ 10mA
Vce Saturation (Max)	500mV	500mV	500mV
Operating Temperature	-40°C ~ 100°C	-40°C ~ 100°C	-55°C ~ 100°C
Mounting Type	Through Hole	Through Hole	Through Hole
Product Status	Obsolete	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For direct replacement of 4N28VM: Select 4N28M. This part maintains identical electrical specifications and mechanical compatibility while offering active product status and ROHS3 compliance. The onsemi manufacturer continuity ensures consistent performance characteristics and supply chain reliability.

For applications requiring enhanced performance margins: Select 4N28-X001. This Vishay part provides 5000Vrms isolation voltage (830Vrms higher than the original specification), 70V maximum output voltage (40V higher), and extended lower temperature rating (-55°C versus -40°C). These enhancements provide additional design margin for demanding isolation and temperature applications while maintaining pin-compatible 6-DIP packaging and identical switching characteristics.

Both substitute parts are ROHS3 compliant and carry active product status, ensuring long-term availability and regulatory compliance for new designs and legacy system maintenance.

Frequently Asked Questions (FAQ)

Q: Can 4N28M be used as a direct replacement for 4N28VM?

A: Yes. The 4N28M is electrically and mechanically identical to the 4N28VM, with matching isolation voltage (4170Vrms), output voltage rating (30V), current transfer ratio (10% @ 10mA), and 6-DIP package configuration. The primary difference is product status: 4N28M is active while 4N28VM is obsolete.

Q: What are the key differences between 4N28M and 4N28-X001?

A: Both parts are pin-compatible 6-DIP optoisolators with identical current transfer ratios and saturation characteristics. The 4N28-X001 offers higher isolation voltage (5000Vrms versus 4170Vrms), higher output voltage rating (70V versus 30V), and extended lower operating temperature (-55°C versus -40°C). The 4N28-X001 is manufactured by Vishay rather than onsemi.

Q: Are all substitute parts in the same 6-DIP package?

A: Yes. The 4N28VM, 4N28M, and 4N28-X001 all use the 6-DIP (0.300", 7.62mm) package, enabling direct pin-compatible replacement without PCB modifications.

Q: Which substitute part should be selected for new designs?

A: For new designs requiring the original 4N28VM specifications, 4N28M is the recommended choice due to manufacturer continuity with onsemi and identical electrical performance. For applications requiring enhanced isolation voltage or output voltage capability, 4N28-X001 provides additional design margin while maintaining compatibility.

Q: Are both substitute parts RoHS compliant?

A: Yes. Both 4N28M and 4N28-X001 are ROHS3 compliant, meeting current environmental and regulatory requirements for electronic components.

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