4N33S Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N33S is an optoisolator with Darlington output and base connection, manufactured by onsemi. This component provides 5300Vrms isolation in a 6-SMD surface mount package. The 4N33S is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Substiute Parts

4N33S

onsemiIn Stock: 232644N33S Datasheet

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4N33SM

onsemiIn Stock: 14404N33SM Datasheet

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4N33SM

onsemiIn Stock: 14404N33SM Datasheet

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4N33SMT&R

Isocom Components 2004 LTDIn Stock: 20324N33SMT&R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the 4N33S is determined by the following critical parameters:

• Number of Channels: Must be 1 channel
• Output Type: Must be Darlington with Base
• Mounting Type: Must be Surface Mount
• Package / Case: Must be 6-SMD, Gull Wing
• Voltage - Output (Max): Must be 30V
• Current Transfer Ratio (Min): Must be 500% @ 10mA
• Vce Saturation (Max): Must be 1V
• Input Type: Must be DC

The 4N33S has two identified substitute parts: 4N33SM (onsemi) and 4N33SMT&R (Isocom Components 2004 LTD). Both maintain the core functional parameters required for direct substitution, though with variations in isolation voltage rating and output current capacity.

Parameter Comparison

Engineering Selection Recommendations

4N33SM (onsemi): This substitute maintains active product status and is manufactured by the original supplier. It shares identical electrical characteristics with the 4N33S including current transfer ratio, output voltage, and saturation voltage. The isolation voltage is reduced from 5300Vrms to 4170Vrms, and the operating temperature minimum is -40°C versus -55°C. This part is ROHS3 compliant and available in Tube packaging.

4N33SMT&R (Isocom Components 2004 LTD): This substitute is also active and maintains the full operating temperature range of -55°C to 100°C matching the original 4N33S. However, the output current is limited to 50mA compared to 150mA in the main part, and the isolation voltage specification differs significantly (7.5Vpk). This part is ROHS3 compliant and supplied in Tape & Reel packaging.

Selection between substitutes depends on application requirements for isolation voltage, output current capacity, and operating temperature range.

Frequently Asked Questions (FAQ)

Q: Can 4N33SM directly replace 4N33S in all applications?

A: 4N33SM maintains the same output type (Darlington with Base), current transfer ratio, output voltage, and saturation voltage as 4N33S. The primary differences are lower isolation voltage (4170Vrms vs 5300Vrms) and narrower operating temperature range (-40°C to 100°C vs -55°C to 100°C). Substitution is valid only if your application does not require the higher isolation voltage or extended low-temperature operation.

Q: What are the key differences between 4N33SM and 4N33SMT&R?

A: Both are active alternatives to the obsolete 4N33S. 4N33SM is supplied by onsemi in Tube packaging with 150mA output current. 4N33SMT&R is supplied by Isocom Components in Tape & Reel packaging with reduced output current of 50mA. 4N33SMT&R maintains the full -55°C to 100°C temperature range of the original part.

Q: Does packaging type affect electrical performance?

A: No. Packaging type (Tube vs Tape & Reel) affects procurement and assembly processes but does not alter electrical characteristics. Selection between packaging options depends on manufacturing requirements and volume.

Q: Are all substitute parts RoHS compliant?

A: 4N33SM and 4N33SMT&R are both ROHS3 compliant. The original 4N33S RoHS status is not specified in the provided data.

Q: What is the significance of the isolation voltage difference?

A: Isolation voltage determines the maximum voltage differential that can be safely applied across the optoisolator's isolation barrier. 4N33SM at 4170Vrms provides lower isolation than 4N33S at 5300Vrms. Applications requiring high-voltage isolation should retain the original 4N33S specification or select 4N33SMT&R if available inventory permits.