4N25S Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N25S is a single-channel optoisolator transistor with base output manufactured by onsemi, rated for 5300Vrms isolation voltage. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The 4N25S operates with DC input, transistor output with base connection, and is packaged in 6-SMD surface mount configuration suitable for high-density circuit board applications.

Key Parameters

Parameter	Value
Manufacturer Part Number	4N25S
Manufacturer	onsemi
Category	Optoisolators
Number of Channels	1
Voltage - Isolation	5300Vrms
Current Transfer Ratio (Min)	20% @ 10mA
Turn On / Turn Off Time (Typ)	2µs, 2µs
Input Type	DC
Output Type	Transistor with Base
Voltage - Output (Max)	30V
Voltage - Forward (Vf) (Typ)	1.18V
Current - DC Forward (If) (Max)	100 mA
Vce Saturation (Max)	500mV
Operating Temperature	-55°C ~ 100°C
Mounting Type	Surface Mount
Package / Case	6-SMD, Gull Wing
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the 4N25S optoisolator is determined by the following critical parameters:

Isolation Voltage Compatibility: The 4N25S operates at 5300Vrms isolation. Substitute parts must maintain isolation voltage at or above the application requirement. Parts with lower isolation ratings (2500Vrms) are suitable only for applications with reduced isolation demands.

Output Characteristics: All substitute parts maintain transistor output with base connection, DC input type, and identical switching times (2µs turn-on/off), ensuring functional compatibility in signal isolation circuits.

Thermal and Electrical Operating Range: All candidates operate across -55°C to 100°C temperature range with 500mV maximum Vce saturation, meeting the same performance envelope.

Package Standardization: All substitute parts use 6-SMD Gull Wing surface mount packaging, maintaining PCB layout compatibility.

Current Transfer Ratio: Minimum 20% @ 10mA is maintained across all substitutes, ensuring consistent optical coupling efficiency.

Substitutes are grouped into two categories: direct functional equivalents with comparable isolation voltage (4N25SM, 4N25-X007T, 4N25-X009T, 4N25-X017) and lower-isolation alternatives (4N25-300E, 4N25-500E, 4N25S-TA, 4N25S-TA1) suitable for applications not requiring 5300Vrms isolation.

Parameter Comparison

Parameter	4N25S (Main)	4N25SM	4N25-X007T	4N25-X009T	4N25-X017	4N25-300E	4N25-500E	4N25S-TA	4N25S-TA1
Manufacturer	onsemi	onsemi	Vishay	Vishay	Vishay	Broadcom	Broadcom	Lite-On	Lite-On
Voltage - Isolation	5300Vrms	4170Vrms	5000Vrms	5000Vrms	5000Vrms	2500Vrms	2500Vrms	2500Vrms	2500Vrms
Current Transfer Ratio (Min)	20% @ 10mA	20% @ 10mA	20% @ 10mA	20% @ 10mA	20% @ 10mA	20% @ 10mA	20% @ 10mA	20% @ 10mA	20% @ 10mA
Turn On / Turn Off Time (Typ)	2µs, 2µs	2µs, 2µs	2µs, 2µs	2µs, 2µs	2µs, 2µs	—	—	—	—
Rise / Fall Time (Typ)	—	—	2µs, 2µs	2µs, 2µs	2µs, 2µs	3µs, 3µs	3µs, 3µs	3µs, 3µs	3µs, 3µs
Input Type	DC	DC	DC	DC	DC	DC	DC	DC	DC
Output Type	Transistor with Base	Transistor with Base	Transistor with Base	Transistor with Base	Transistor with Base	Transistor with Base	Transistor with Base	Transistor with Base	Transistor with Base
Voltage - Output (Max)	30V	30V	70V	70V	70V	30V	30V	30V	30V
Current - Output / Channel	—	—	50mA	50mA	50mA	100mA	100mA	100mA	100mA
Voltage - Forward (Vf) (Typ)	1.18V	1.18V	1.36V	1.36V	1.36V	1.2V	1.2V	1.2V	1.2V
Current - DC Forward (If) (Max)	100 mA	60 mA	60 mA	60 mA	60 mA	80 mA	80 mA	80 mA	80 mA
Vce Saturation (Max)	500mV	500mV	500mV	500mV	500mV	500mV	500mV	500mV	500mV
Operating Temperature	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	6-SMD, Gull Wing	6-SMD, Gull Wing	6-SMD, Gull Wing	6-SMD, Gull Wing	6-SMD, Gull Wing	6-SMD, Gull Wing	6-SMD, Gull Wing	6-SMD, Gull Wing	6-SMD, Gull Wing
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

High-Isolation Applications (≥5000Vrms Required): Select 4N25-X007T, 4N25-X009T, or 4N25-X017 from Vishay Semiconductor Opto Division. These parts maintain 5000Vrms isolation voltage, matching the primary isolation requirement of the obsolete 4N25S. All three are active products with ROHS3 compliance and unlimited MSL rating. The 4N25-X009T and 4N25-X007T are available in Tape & Reel packaging with higher inventory (12,880 and 12,570 units respectively), supporting volume production. The 4N25-X017 offers Tube packaging alternative with 4,000 units in stock.

Mid-Isolation Applications (4000-4500Vrms Acceptable): The 4N25SM from onsemi provides 4170Vrms isolation with active product status and ROHS3 compliance. This part maintains the original onsemi manufacturer lineage and identical switching characteristics (2µs turn-on/off). Current inventory of 3,000 units supports standard procurement volumes.

Lower-Isolation Applications (2500Vrms Acceptable): The 4N25S-TA1 from Lite-On Inc. is the preferred choice for applications not requiring isolation above 2500Vrms. This part is active, ROHS3 compliant, and available in Cut Tape & Digi-Reel packaging with 10,300 units in stock, providing excellent procurement flexibility. The 4N25-300E and 4N25-500E from Broadcom Limited are alternative options with identical 2500Vrms isolation and active status, though with lower inventory availability (1,180 and 4,020 units respectively).

All substitute parts maintain the 6-SMD Gull Wing surface mount package, ensuring direct PCB layout compatibility without redesign. The 20% minimum current transfer ratio is preserved across all substitutes, maintaining optical coupling performance in signal isolation circuits.

Frequently Asked Questions (FAQ)

Q: Can the 4N25S be directly replaced with the 4N25SM? A: The 4N25SM is functionally compatible for applications where 4170Vrms isolation is sufficient. Both parts share identical switching times (2µs), current transfer ratio (20% @ 10mA), and output voltage rating (30V). The primary difference is reduced isolation voltage (4170Vrms vs. 5300Vrms). Verify application isolation requirements before substitution.

Q: What is the difference between Vishay 4N25-X007T and 4N25-X009T? A: Both parts are electrically identical with 5000Vrms isolation, 2µs switching times, and 70V maximum output voltage. The primary difference is packaging: 4N25-X009T is supplied in Tape & Reel (12,880 units available), while 4N25-X007T is also Tape & Reel (12,570 units available). Both are suitable for high-volume surface mount assembly.

Q: Can I use 4N25S-TA1 in place of 4N25S? A: The 4N25S-TA1 is compatible only for applications where 2500Vrms isolation meets the design requirement. While both parts maintain identical switching characteristics and 6-SMD packaging, the isolation voltage is significantly lower (2500Vrms vs. 5300Vrms). Do not substitute if higher isolation is required for safety or regulatory compliance.

Q: What packaging options are available for high-isolation substitutes? A: The Vishay 4N25-X009T and 4N25-X007T are supplied in Tape & Reel (TR) packaging for automated assembly. The 4N25-X017 is available in Tube packaging. All three maintain 5000Vrms isolation and are suitable for production environments requiring different packaging formats.

Q: Are all substitute parts RoHS3 compliant? A: All active substitute parts listed (4N25SM, 4N25-X007T, 4N25-X009T, 4N25-X017, 4N25-300E, 4N25-500E, 4N25S-TA, 4N25S-TA1) are ROHS3 compliant. The original 4N25S does not specify RoHS status due to its obsolete classification. Compliance verification is recommended for new designs.

Q: What is the maximum forward current difference between substitutes? A: The 4N25S and 4N25SM support 100mA maximum DC forward current, while Vishay parts (4N25-X007T, 4N25-X009T, 4N25-X017) and Lite-On/Broadcom alternatives support 60-80mA. Verify input LED drive circuit design to ensure compatibility with the selected substitute's current rating.

Q: Do all substitutes maintain the same operating temperature range? A: Yes, all substitute parts operate across -55°C to 100°C, matching the original 4N25S specification. Thermal performance is consistent across all candidates.

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