4N33 Optoisolator Darlington Equivalent & Substitute Parts

Part Overview

The 4N33 is an optoisolator with Darlington output configuration, manufactured by onsemi, designed for high-voltage isolation applications. It features 5300Vrms isolation voltage, single-channel Darlington output with base connection, and operates across -55°C to 100°C. The 4N33 is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Manufacturer Part Number	4N33
Manufacturer	onsemi
Category	Optoisolators
Number of Channels	1
Voltage - Isolation	5300Vrms
Current Transfer Ratio (Min)	500% @ 10mA
Output Type	Darlington with Base
Voltage - Output (Max)	30V
Current - Output / Channel	150mA
Turn On / Turn Off Time (Typ)	5µs, 100µs (Max)
Operating Temperature	-55°C ~ 100°C
Package / Case	6-DIP (0.300", 7.62mm)
Mounting Type	Through Hole
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the 4N33 optoisolator are grouped based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

Voltage - Isolation: 5300Vrms or 5000Vrms (within acceptable range)
Number of Channels: 1 (single channel only)
Output Type: Darlington with Base (required configuration)
Package / Case: 6-DIP form factor (0.300" or 0.400" pitch acceptable)
Mounting Type: Through Hole
Operating Temperature Range: -55°C ~ 100°C minimum

Secondary Compatibility Parameters:

Current Transfer Ratio (Min): 100% or higher @ specified current
Voltage - Output (Max): 25V or higher
Current - Output / Channel: 100mA or higher
Turn On / Turn Off Time: Within application timing requirements

Parts meeting these criteria are considered functionally equivalent for the 4N33 application space.

Parameter Comparison

Part Number	Manufacturer	Isolation Voltage	CTR (Min)	Output Type	Vout (Max)	Iout / Channel	Package	Status
4N33	onsemi	5300Vrms	500% @ 10mA	Darlington w/ Base	30V	150mA	6-DIP (0.300")	Obsolete
4N33M	Fairchild Semiconductor	5000Vrms	500% @ 10mA	Darlington w/ Base	55V	—	6-DIP (0.400")	Active
4N30	onsemi	5300Vrms	100% @ 10mA	Darlington w/ Base	30V	150mA	6-DIP (0.300")	Obsolete
4N32	Vishay Semiconductor Opto Division	5300Vrms	500% @ 10mA	Darlington w/ Base	30V	100mA	6-DIP (0.300")	Obsolete
4N33-X001	Vishay Semiconductor Opto Division	5300Vrms	500% @ 10mA	Darlington w/ Base	30V	100mA	6-DIP (0.300")	Active
H11B1	onsemi	5300Vrms	500% @ 1mA	Darlington w/ Base	25V	—	6-DIP (0.300")	Obsolete
H11B2	onsemi	5300Vrms	200% @ 1mA	Darlington w/ Base	25V	—	6-DIP (0.300")	Obsolete
H11B3	Fairchild Semiconductor	5000Vrms	100% @ 1mA	Darlington w/ Base	55V	—	6-DIP (0.300")	Obsolete
MCA2230	Isocom Components 2004 LTD	5300Vrms	100% @ 10mA	Darlington w/ Base	30V	—	6-DIP (0.300")	Active

Engineering Selection Recommendations

Direct Equivalents (Highest Compatibility): The 4N32 and 4N33-X001 provide the closest functional match to the 4N33. Both maintain 5300Vrms isolation voltage, Darlington output with base, 6-DIP (0.300") package, and -55°C to 100°C operating range. The 4N33-X001 is preferred where active product status is required, as it carries ROHS3 compliance certification.

Active Product Alternatives: The 4N33M (Fairchild Semiconductor) and MCA2230 (Isocom Components) are active products suitable for new designs. The 4N33M offers higher output voltage capability (55V vs. 30V) but uses a 0.400" DIP pitch. The MCA2230 maintains the 0.300" pitch and 5300Vrms isolation with active status and ROHS3 compliance.

Compliance Considerations: For applications requiring RoHS compliance, the 4N33-X001, 4N33M, H11B3, and MCA2230 all carry ROHS3 certification. The 4N33 original part and 4N30, 4N32, H11B1, and H11B2 do not specify RoHS status in provided data.

Obsolete Part Substitution: When replacing obsolete 4N33 units in existing systems, prioritize active-status alternatives (4N33-X001, 4N33M, MCA2230) to ensure long-term supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can the 4N30 directly replace the 4N33? A: The 4N30 shares identical package, isolation voltage, and output configuration. However, it specifies 100% minimum CTR @ 10mA versus the 4N33's 500%, which may affect circuit performance in applications dependent on higher current transfer ratios.

Q: What is the difference between 4N33 and 4N32? A: Both parts maintain 5300Vrms isolation and Darlington output in 6-DIP (0.300") package. The 4N33 supports 150mA output current per channel, while the 4N32 is rated for 100mA. The 4N33 specifies 500% CTR; the 4N32 also specifies 500% CTR. Forward voltage differs slightly (1.2V vs. 1.25V).

Q: Is the 4N33M a suitable replacement? A: The 4N33M is functionally compatible for most applications. It maintains 500% CTR and Darlington output configuration. Key differences: isolation voltage is 5000Vrms (vs. 5300Vrms), output voltage rating is 55V (vs. 30V), and package pitch is 0.400" (vs. 0.300"). Verify PCB footprint compatibility before substitution.

Q: Why should I choose 4N33-X001 over the original 4N33? A: The 4N33-X001 is an active product with ROHS3 compliance certification, ensuring continued availability and environmental compliance. It maintains identical electrical specifications and 6-DIP (0.300") package as the original 4N33.

Q: Can H11B series parts replace the 4N33? A: H11B1, H11B2, and H11B3 share the 6-DIP package and 5300Vrms isolation. However, they specify different CTR test conditions (@ 1mA vs. @ 10mA), lower maximum output voltage (25V vs. 30V for H11B1/H11B2), and different timing characteristics. Verify application requirements before substitution.

Q: What is the advantage of MCA2230 as a substitute? A: The MCA2230 is an active product with ROHS3 compliance, 5300Vrms isolation, and 6-DIP (0.300") package matching the 4N33. It provides long-term supply availability for applications requiring environmental compliance.

Q: Are there package compatibility concerns with 6-DIP substitutes? A: Most substitutes use 6-DIP (0.300", 7.62mm) package identical to the 4N33. The 4N33M uses 6-DIP (0.400", 10.16mm) pitch, requiring PCB footprint verification. Confirm lead spacing before board-level substitution.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message