4N33VM Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N33VM is an optoisolator with Darlington output manufactured by onsemi, rated for 4170Vrms isolation voltage in a 6-DIP through-hole package. This component is currently active in production. Equivalent and substitute parts are identified based on matching electrical characteristics, package compatibility, and functional performance within the optoisolator Darlington with base output category.

Key Parameters

Parameter	4N33VM Specification
Manufacturer	onsemi
Number of Channels	1
Voltage - Isolation	4170Vrms
Current Transfer Ratio (Min)	500% @ 10mA
Output Type	Darlington with Base
Voltage - Output (Max)	30V
Current - Output / Channel	150mA
Vce Saturation (Max)	1V
Operating Temperature	-40°C ~ 100°C
Package / Case	6-DIP (0.300", 7.62mm)
Mounting Type	Through Hole
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts are classified into two categories based on parametric alignment with the 4N33VM:

Parametric Equivalents share identical or functionally equivalent electrical specifications across isolation voltage, current transfer ratio, output type, and package dimensions. These parts are direct functional replacements within the same performance envelope.

Similar Parts maintain the same output type, package form factor, and general functional category but may differ in isolation voltage rating, current transfer ratio specifications, or operating temperature range. These parts require application-level verification of parameter compatibility.

The critical parameters determining substitution eligibility are:

Number of Channels: 1
Output Type: Darlington with Base
Package / Case: 6-DIP through-hole configuration
Isolation Voltage: minimum 4170Vrms
Current Transfer Ratio (Min): minimum 500% @ 10mA
Vce Saturation (Max): 1V
Mounting Type: Through Hole

Parameter Comparison

Part Number	Manufacturer	Isolation Voltage	CTR (Min)	Output (Max)	Output Current	Vce Sat (Max)	Temp Range	Package	Status
4N33VM	onsemi	4170Vrms	500% @ 10mA	30V	150mA	1V	-40°C ~ 100°C	6-DIP (0.300")	Active
4N32M	onsemi	4170Vrms	500% @ 10mA	30V	150mA	1V	-40°C ~ 100°C	6-DIP (0.300")	Active
4N32VM	onsemi	4170Vrms	500% @ 10mA	30V	150mA	1V	-40°C ~ 100°C	6-DIP (0.300")	Active
4N33M	Fairchild Semiconductor	5000Vrms	500% @ 10mA	55V	—	1V	-55°C ~ 100°C	6-DIP (0.400")	Active
4N32	Vishay Semiconductor Opto Division	5300Vrms	500% @ 10mA	30V	100mA	1V	-55°C ~ 100°C	6-DIP (0.300")	Obsolete
4N33	onsemi	5300Vrms	500% @ 10mA	30V	150mA	1V	-55°C ~ 100°C	6-DIP (0.300")	Obsolete
H11B1	onsemi	5300Vrms	500% @ 1mA	25V	—	1V	-55°C ~ 100°C	6-DIP (0.300")	Obsolete
H11B2	onsemi	5300Vrms	200% @ 1mA	25V	—	1V	-55°C ~ 100°C	6-DIP (0.300")	Obsolete
H11B3	Fairchild Semiconductor	5000Vrms	100% @ 1mA	55V	—	1V	-55°C ~ 100°C	6-DIP (0.300")	Obsolete
MCA2230	Isocom Components 2004 LTD	5300Vrms	100% @ 10mA	30V	—	1V	-55°C ~ 100°C	6-DIP (0.300")	Active
MCA2231	Isocom Components 2004 LTD	5300Vrms	500% @ 10mA	30V	—	1V	-55°C ~ 100°C	6-DIP (0.300")	Active

Engineering Selection Recommendations

Direct Parametric Equivalents (Recommended for Direct Substitution)

4N32M and 4N32VM are parametric equivalents to the 4N33VM. Both parts are manufactured by onsemi with identical electrical specifications: 4170Vrms isolation, 500% CTR @ 10mA, 30V maximum output, 150mA output current, and 1V Vce saturation. All three parts are active products with ROHS3 compliance. The primary difference is packaging format (Tube vs. Bulk), which does not affect functional performance. These parts are suitable for direct substitution in applications requiring the specified performance envelope.

Higher Isolation Voltage Alternatives

4N33M (Fairchild Semiconductor) and MCA2231 (Isocom) provide higher isolation voltage ratings (5000Vrms and 5300Vrms respectively) with matching 500% CTR @ 10mA. Both are active products with ROHS3 compliance. 4N33M features 55V maximum output voltage compared to 30V on the 4N33VM, and operates across -55°C to 100°C. MCA2231 maintains 30V output with extended temperature range. These parts are suitable for applications requiring enhanced isolation margin.

Obsolete Parts with Similar Characteristics

4N33, 4N32 (Vishay), H11B1, H11B2, and H11B3 are obsolete products. While these parts share the 6-DIP package and Darlington output configuration, they are no longer in active production. 4N33 and 4N32 (Vishay) maintain 500% CTR but with higher isolation ratings (5300Vrms). H11B series parts feature lower CTR specifications (100-500% @ 1mA) and reduced output voltage ratings (25V). These parts should be used only when existing inventory is available and new production is not required.

Lower CTR Alternative

MCA2230 (Isocom) provides 100% CTR @ 10mA with 5300Vrms isolation and 30V output. This part is active and ROHS3 compliant but features significantly lower current transfer ratio than the 4N33VM. Selection requires application-level verification that lower CTR meets circuit requirements.

Frequently Asked Questions (FAQ)

Q: Can 4N32M or 4N32VM be used as direct replacements for 4N33VM?

A: Yes. Both 4N32M and 4N32VM are parametric equivalents with identical isolation voltage (4170Vrms), current transfer ratio (500% @ 10mA), output voltage (30V), output current (150mA), and Vce saturation (1V). The only difference is packaging format. Both are active onsemi products with ROHS3 compliance.

Q: What is the difference between 4N33VM and 4N33M?

A: 4N33M is manufactured by Fairchild Semiconductor and features higher isolation voltage (5000Vrms vs. 4170Vrms), higher maximum output voltage (55V vs. 30V), and extended operating temperature range (-55°C to 100°C vs. -40°C to 100°C). The package dimensions also differ (0.400" vs. 0.300"). Both maintain 500% CTR @ 10mA and 1V Vce saturation.

Q: Are obsolete parts like 4N33 and H11B3 still suitable for new designs?

A: Obsolete parts are not recommended for new designs. While 4N33 and H11B3 share the 6-DIP package and Darlington output type, they are no longer in active production. Active alternatives such as 4N32M, 4N32VM, 4N33M, MCA2230, and MCA2231 should be used for new applications.

Q: What does Current Transfer Ratio (CTR) mean, and why does it matter for substitution?

A: Current Transfer Ratio is the ratio of output collector current to input LED current, expressed as a percentage. The 4N33VM specifies 500% CTR @ 10mA, meaning the output current is five times the input current at 10mA input. Parts with lower CTR (such as MCA2230 at 100% or H11B3 at 100%) require higher input current to achieve the same output current and may not be suitable for all applications.

Q: Can I use MCA2231 instead of 4N33VM?

A: MCA2231 is functionally compatible with matching 500% CTR @ 10mA, 5300Vrms isolation, 30V output, and 1V Vce saturation. However, MCA2231 is manufactured by Isocom Components and features extended operating temperature range (-55°C to 100°C). The part is active and ROHS3 compliant. Application-level verification of manufacturer-specific performance characteristics is recommended.

Q: What is the significance of the 6-DIP package dimension difference (0.300" vs. 0.400")?

A: The 6-DIP package dimension affects PCB layout and component spacing. 4N33VM uses 0.300" (7.62mm) spacing, while 4N33M uses 0.400" (10.16mm) spacing. These are not mechanically interchangeable on the same PCB without layout modification. Verify PCB footprint compatibility before substitution.

Q: Are all substitute parts ROHS3 compliant?

A: Active products (4N32M, 4N32VM, 4N33M, MCA2230, MCA2231) are ROHS3 compliant. Obsolete parts (4N33, 4N32 Vishay, H11B1, H11B2, H11B3) have varying compliance status. Verify compliance requirements for your application before selecting a substitute.

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