4N33 Optoisolator Darlington with Base - Equivalent & Substitute Parts

Part Overview

The 4N33 is a single-channel optoisolator with Darlington output and base connection, rated for 5300Vrms isolation voltage. Manufactured by Vishay Semiconductor Opto Division, this component is classified as Last Time Buy, indicating discontinued production with limited inventory availability. The 4N33 operates in Through Hole 6-DIP packaging and is suitable for applications requiring galvanic isolation with Darlington output configuration. Due to its Last Time Buy status, identifying parametrically equivalent alternatives is essential for design continuity and long-term supply chain planning.

Substiute Parts

4N33

Vishay Semiconductor Opto DivisionIn Stock: 46644N33 Datasheet

Current PartRFQ

4N32

Vishay Semiconductor Opto DivisionIn Stock: 1526684N32 Datasheet

Parametric EquivalentRFQ

4N33-X001

Vishay Semiconductor Opto DivisionIn Stock: 8194N33-X001 Datasheet

Parametric EquivalentRFQ

4N33M

Fairchild SemiconductorIn Stock: 138074N33M Datasheet

MFR RecommendedRFQ

MCA230

Isocom Components 2004 LTDIn Stock: 4291MCA230 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 4N33 is determined by the following critical parameters:

• Isolation Voltage: 5300Vrms (minimum requirement)
• Output Configuration: Darlington with Base
• Number of Channels: Single channel (1)
• Package Type: 6-DIP Through Hole
• Current Transfer Ratio: 500% @ 10mA (minimum)
• Output Voltage Rating: 30V (maximum)
• Output Current: 100mA per channel
• Operating Temperature Range: -55°C ~ 100°C
• Input Type: DC

Substitute parts are grouped into two categories: Parametric Equivalents (identical electrical and mechanical specifications) and Manufacturer Recommended alternatives (functionally compatible with minor parameter variations).

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: 4N33-X001

The 4N33-X001 is the optimal substitute for the 4N33. Both parts are manufactured by Vishay Semiconductor Opto Division and share identical electrical specifications: 5300Vrms isolation voltage, 500% current transfer ratio at 10mA, 30V maximum output voltage, and 100mA output current. The 4N33-X001 maintains the same 6-DIP (0.300", 7.62mm) package footprint and is currently in Active product status with 710 units in stock. Both parts are ROHS3 compliant and operate across the -55°C to 100°C temperature range.

Secondary Substitute: 4N32

The 4N32 is a parametrically equivalent alternative also from Vishay Semiconductor Opto Division, matching all critical electrical parameters of the 4N33. However, the 4N32 is classified as Obsolete, indicating no further production. With 152,644 units in inventory, the 4N32 remains available for immediate procurement but represents a declining supply source. The 4N32 is suitable only for applications where long-term availability is not a design constraint.

Alternative Substitute: MCA230

The MCA230, manufactured by Isocom Components 2004 LTD, provides functional compatibility with the 4N33 in the same 6-DIP (0.300", 7.62mm) package. The MCA230 maintains 5300Vrms isolation voltage and Darlington with Base output configuration. The primary difference is a reduced minimum current transfer ratio of 100% @ 10mA compared to the 4N33's 500%, and a slightly longer turn-on time of 10µs versus 5µs. The MCA230 is ROHS3 compliant and currently Active with 4,239 units in stock. This substitute is suitable for applications where the lower current transfer ratio and extended switching time are acceptable.

Not Recommended: 4N33M

The 4N33M, manufactured by Fairchild Semiconductor, exhibits a reduced isolation voltage rating of 5000Vrms compared to the 4N33's 5300Vrms specification. Additionally, the 4N33M uses a larger 6-DIP (0.400", 10.16mm) package footprint, which may not fit existing PCB layouts designed for the standard 0.300" package. The 4N33M is suitable only for applications with relaxed isolation voltage requirements and PCB designs accommodating the larger package.

Frequently Asked Questions (FAQ)

Q: Can the 4N32 be used as a direct replacement for the 4N33?

A: The 4N32 is parametrically equivalent to the 4N33 in all critical electrical specifications. However, the 4N32 is classified as Obsolete with no further manufacturing. While immediate substitution is electrically valid, the 4N32 should not be selected for new designs or applications requiring long-term component availability. The 4N33-X001 is the preferred alternative for sustained supply.

Q: What is the key difference between the 4N33 and MCA230?

A: Both parts share identical isolation voltage (5300Vrms), output configuration (Darlington with Base), and package footprint (6-DIP 0.300"). The MCA230 has a lower minimum current transfer ratio of 100% @ 10mA versus the 4N33's 500%, and a slightly longer turn-on time of 10µs versus 5µs. Applications sensitive to switching speed or requiring higher current transfer ratios should use the 4N33 or 4N33-X001.

Q: Is the 4N33M compatible with existing 4N33 PCB designs?

A: The 4N33M uses a larger 6-DIP (0.400", 10.16mm) package compared to the 4N33's 6-DIP (0.300", 7.62mm) package. This dimensional difference may prevent direct PCB mounting without layout modifications. Additionally, the 4N33M has a reduced isolation voltage rating of 5000Vrms. The 4N33M is not recommended for direct PCB substitution.

Q: Why is the 4N33-X001 preferred over the 4N32 despite both being parametrically equivalent?

A: The 4N33-X001 is currently in Active product status with ongoing manufacturing, while the 4N32 is Obsolete with no future production. For new designs and applications requiring component availability beyond current inventory depletion, the 4N33-X001 ensures long-term supply chain continuity.

Q: Are all substitute parts ROHS3 compliant?

A: The 4N33, 4N32, 4N33-X001, and MCA230 are all ROHS3 compliant. The 4N33M compliance status is not specified in the provided data. Designs requiring confirmed ROHS3 compliance should use the 4N33-X001 or MCA230.

Q: What is the significance of the 500% current transfer ratio specification?

A: The current transfer ratio indicates the ratio of output current to input current. A 500% ratio means the output current is five times the input current at 10mA input. The MCA230's 100% ratio provides lower current amplification, which may affect circuit performance in applications designed for the higher 500% specification. Verify circuit requirements before substituting with lower current transfer ratio alternatives.