4N32SD Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N32SD 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 4N32SD is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain functional compatibility across isolation voltage, output configuration, channel count, and thermal operating range.

Substiute Parts

4N32SD

onsemiIn Stock: 57254N32SD Datasheet

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4N32SR2M

onsemiIn Stock: 222394N32SR2M Datasheet

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4N32SM

onsemiIn Stock: 22754N32SM Datasheet

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4N32SMT&R

Isocom Components 2004 LTDIn Stock: 8844N32SMT&R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 4N32SD is determined by the following critical parameters:

• Number of Channels: Must equal 1
• Output Type: Must be Darlington with Base
• Voltage - Output (Max): Must be 30V or greater
• Current - Output / Channel: Must be 150mA or greater
• Current Transfer Ratio (Min): Must be 500% @ 10mA or greater
• Vce Saturation (Max): Must be 1V or less
• Mounting Type: Surface Mount preferred for direct replacement
• Package / Case: 6-SMD, Gull Wing preferred for direct replacement
• Moisture Sensitivity Level (MSL): Must be 1 (Unlimited)

Substitute parts are grouped into two categories:

Category A - Direct Substitutes (onsemi 6-SMD Surface Mount): Parts 4N32SR2M and 4N32SM meet all critical electrical parameters and maintain the same base product number (4N32). These parts differ in isolation voltage (4170Vrms vs. 5300Vrms) and packaging format (Tape & Reel or Tube), but remain functionally compatible for applications where the lower isolation rating is acceptable.

Category B - Cross-Manufacturer Substitute (Through-Hole Package): Part 4N32SMT&R from Isocom Components 2004 LTD maintains Darlington output configuration and base connection but uses a 6-DIP through-hole package. This part has significantly lower isolation voltage (7.5Vpk) and reduced output current (50mA), making it suitable only for applications with relaxed isolation and current requirements.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Preferred): Select 4N32SR2M or 4N32SM. Both parts are active products from onsemi with ROHS3 compliance and maintain the same 6-SMD surface mount package. The 4N32SR2M is supplied in Tape & Reel format with 22,200 units in stock, making it suitable for automated assembly. The 4N32SM is supplied in Tube format with 2,240 units in stock, suitable for manual assembly or lower-volume applications. Both parts operate at -40°C to 100°C, which is acceptable for most industrial applications where the 4N32SD's -55°C lower limit is not required.

For Applications with Relaxed Isolation Requirements: The 4N32SMT&R from Isocom Components 2004 LTD is suitable only when isolation voltage can be reduced from 5300Vrms to 7.5Vpk and output current can be limited to 50mA maximum. This part uses a through-hole 6-DIP package and maintains the full -55°C to 100°C operating temperature range. ROHS3 compliance is confirmed.

Isolation Voltage Consideration: The 4N32SR2M and 4N32SM operate at 4170Vrms isolation, which is lower than the 4N32SD's 5300Vrms. Applications requiring the full 5300Vrms isolation rating cannot use these substitutes.

Frequently Asked Questions (FAQ)

Q: Can 4N32SR2M or 4N32SM directly replace 4N32SD in existing designs?

A: Both parts maintain identical electrical performance for output configuration, current transfer ratio, output voltage, and saturation characteristics. The primary difference is isolation voltage (4170Vrms vs. 5300Vrms). Direct replacement is possible if the application does not require 5300Vrms isolation. Both parts use the same 6-SMD surface mount package and pinout, requiring no PCB modifications.

Q: What is the difference between 4N32SR2M and 4N32SM?

A: Both parts are electrically identical onsemi optoisolators with 4170Vrms isolation and 6-SMD surface mount packages. The difference is packaging format: 4N32SR2M is supplied in Tape & Reel (TR) format for automated pick-and-place assembly, while 4N32SM is supplied in Tube format for manual handling. Select based on assembly process requirements.

Q: Why is 4N32SMT&R not recommended as a primary substitute?

A: The 4N32SMT&R has two significant limitations: isolation voltage is reduced to 7.5Vpk (not Vrms), and maximum output current is 50mA compared to 150mA for the 4N32SD. Additionally, it uses a through-hole 6-DIP package instead of surface mount, requiring different PCB layout and assembly process. Use only when application requirements permit these reductions.

Q: Are all substitute parts ROHS3 compliant?

A: The 4N32SR2M and 4N32SM are confirmed ROHS3 compliant. The 4N32SMT&R is also ROHS3 compliant. The original 4N32SD does not specify RoHS status.

Q: What is the operating temperature range difference?

A: The 4N32SD and 4N32SMT&R operate from -55°C to 100°C. The 4N32SR2M and 4N32SM operate from -40°C to 100°C. Applications requiring operation below -40°C must use the 4N32SD or 4N32SMT&R.

Q: Are moisture sensitivity levels identical across all parts?

A: Yes. All parts including 4N32SD, 4N32SR2M, 4N32SM, and 4N32SMT&R have Moisture Sensitivity Level (MSL) of 1 (Unlimited), indicating no moisture sensitivity restrictions.