4N26S Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N26S is a single-channel optoisolator with transistor output and base connection, rated for 5300Vrms isolation voltage. Manufactured by onsemi in 6-SMD surface mount packaging, this component is classified as obsolete. Due to its discontinued status, equivalent and substitute parts from active manufacturers are necessary for new designs and ongoing production requirements. Substitute parts maintain core functional compatibility while offering varying isolation voltage ratings, output current capabilities, and packaging options from alternative suppliers.

Substiute Parts

4N26S

onsemiIn Stock: 90754N26S Datasheet

Current PartRFQ

4N26SM

Fairchild SemiconductorIn Stock: 221734N26SM Datasheet

DirectRFQ

4N26-X009T

Vishay Semiconductor Opto DivisionIn Stock: 124794N26-X009T Datasheet

SimilarRFQ

4N26S

Fairchild SemiconductorIn Stock: 90534N26S Datasheet

SimilarRFQ

4N26S-TA

Lite-On Inc.In Stock: 11164N26S-TA Datasheet

SimilarRFQ

4N26S-TA1

Lite-On Inc.In Stock: 10554N26S-TA1 Datasheet

SimilarRFQ

4N26SMT&R

Isocom Components 2004 LTDIn Stock: 8024N26SMT&R Datasheet

SimilarRFQ

4N26XSM

Isocom Components 2004 LTDIn Stock: 7574N26XSM Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 4N26S are grouped based on the following critical parameters that determine functional compatibility:

Primary Compatibility Criteria:

• Single-channel configuration (Number of Channels = 1)
• Transistor output with base connection
• 6-SMD surface mount package, Gull Wing orientation
• DC input type
• Operating temperature range encompassing -55°C to 100°C
• Vce saturation maximum of 500mV
• Current transfer ratio minimum of 20% @ 10mA

Secondary Variation Parameters:

• Voltage isolation rating (ranging from 1500Vrms to 5300Vrms)
• Maximum output voltage (30V to 70V)
• Output current per channel (50mA to 100mA)
• Forward voltage (Vf) typical values (1.18V to 1.36V)
• Forward current maximum (60mA to 100mA)
• Switching time specifications (2µs to 3µs)

Parts meeting all primary criteria are classified as direct substitutes despite variations in isolation voltage and output current ratings. These variations remain within acceptable ranges for applications designed around the 4N26S baseline specifications.

Parameter Comparison

Engineering Selection Recommendations

For High-Isolation Applications (5000Vrms and above): Select 4N26-X009T (Vishay), 4N26XSM (Isocom), or 4N26S (Fairchild). These parts maintain isolation voltage ratings at or above 5000Vrms, matching the original 4N26S specification. The 4N26-X009T offers the highest maximum output voltage (70V) and is available in active production status with RoHS3 compliance. The 4N26XSM provides equivalent isolation voltage with active product status and RoHS3 compliance.

For Standard Industrial Applications (1500Vrms isolation acceptable): Select 4N26S-TA or 4N26S-TA1 (Lite-On). Both parts are in active production with RoHS3 compliance and MSL Level 1 rating. These options provide higher output current capability (100mA) compared to the original specification, supporting applications with increased load requirements.

For General-Purpose Optoisolation: Select 4N26SM (Fairchild) for active production status with standard isolation voltage of 4170Vrms. This part is suitable for applications where isolation voltage requirements fall between standard and high-isolation ranges.

Packaging Considerations:

• Tape & Reel (TR) packaging: 4N26-X009T, 4N26S-TA, 4N26S-TA1, 4N26SMT&R
• Tube packaging: 4N26XSM, 4N26S (Fairchild)
• Bulk packaging: 4N26SM

All substitute parts maintain 6-SMD Gull Wing surface mount configuration, ensuring PCB layout compatibility with designs originally specified for the 4N26S.

Frequently Asked Questions (FAQ)

Q: Can 4N26SM replace 4N26S directly? A: 4N26SM is functionally compatible as a substitute. It maintains the same single-channel transistor output configuration, 6-SMD package, and core electrical characteristics. The isolation voltage is 4170Vrms compared to the original 5300Vrms. Selection depends on application isolation requirements. 4N26SM is in active production status, making it suitable for new designs.

Q: What is the difference between 4N26S-TA and 4N26S-TA1? A: Both parts are manufactured by Lite-On Inc. with identical electrical specifications. 4N26S-TA and 4N26S-TA1 differ only in manufacturing lot or internal revision coding. Both are in active production, offer 1500Vrms isolation, and support 100mA output current. Either part is acceptable for substitution purposes.

Q: Is 4N26SMT&R suitable for high-isolation applications? A: No. The 4N26SMT&R (Isocom) specifies 7.5Vpk isolation voltage, which is significantly lower than the original 4N26S rating of 5300Vrms. This part is suitable only for applications with low isolation voltage requirements and should not be selected for high-isolation designs.

Q: Which substitute offers the best compliance status? A: Multiple substitutes offer RoHS3 compliance: 4N26-X009T (Vishay), 4N26S (Fairchild), 4N26S-TA (Lite-On), 4N26S-TA1 (Lite-On), 4N26SMT&R (Isocom), and 4N26XSM (Isocom). All are REACH Unaffected and classified as EAR99 for export control purposes. Selection should be based on isolation voltage and output current requirements rather than compliance, as all active substitutes meet current regulatory standards.

Q: Can I use 4N26-X009T if my design requires 30V maximum output? A: Yes. The 4N26-X009T supports 70V maximum output voltage, which exceeds the 30V requirement. The higher voltage rating provides design margin and does not create compatibility issues. The part is suitable for applications designed around the original 4N26S 30V specification.

Q: What packaging should I specify for high-volume production? A: For high-volume surface mount assembly, specify Tape & Reel (TR) packaging. Available options include 4N26-X009T, 4N26S-TA, 4N26S-TA1, and 4N26SMT&R. Tape & Reel packaging is optimized for automated pick-and-place equipment and reduces handling costs compared to tube or bulk packaging.

Q: Are there temperature range differences between substitutes? A: Most substitutes maintain the -55°C to 100°C operating range. The exception is 4N26SM (Fairchild), which specifies -40°C to 100°C. For applications requiring full -55°C operation, select alternatives that maintain the extended lower temperature limit.

Q: How do switching times compare across substitutes? A: Specified switching times vary. The original 4N26S specifies 2µs turn-on and turn-off times. Substitutes with equivalent specifications include 4N26SM, 4N26S (Fairchild), 4N26SMT&R, and 4N26XSM. The 4N26S-TA and 4N26S-TA1 specify 3µs rise and fall times. The 4N26-X009T does not specify turn-on/turn-off time but lists 2µs rise and fall time. Verify switching time requirements for your specific application before selection.