4N273S Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N273S is a single-channel optoisolator with transistor output and base connection, manufactured by onsemi. It provides 5300Vrms isolation voltage in a 6-SMD surface mount package. The part is currently obsolete, making equivalent substitutes necessary for new designs and production continuity. Substitute parts must maintain compatibility across isolation voltage, output configuration, channel count, and thermal operating range while accommodating packaging and availability constraints.

Key Parameters

Parameter	4N273S Value
Manufacturer	onsemi
Number of Channels	1
Voltage - Isolation	5300Vrms
Output Type	Transistor with Base
Current Transfer Ratio (Min)	10% @ 10mA
Voltage - Output (Max)	30V
Vce Saturation (Max)	500mV
Operating Temperature	-55°C ~ 100°C
Mounting Type	Surface Mount
Package / Case	6-SMD, Gull Wing
Input Type	DC
Voltage - Forward (Vf) (Typ)	1.18V
Current - DC Forward (If) (Max)	100 mA
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution eligibility for the 4N273S is determined by the following critical parameters:

Primary Compatibility Criteria:

Single channel configuration (Number of Channels = 1)
Transistor output with base connection
DC input type
6-SMD, Gull Wing surface mount package
Operating temperature range: -55°C to 100°C
Vce Saturation (Max): 500mV

Secondary Compatibility Criteria:

Isolation voltage: 5300Vrms or higher
Current Transfer Ratio (Min): 10% @ 10mA or better
Output voltage capability: 30V or higher
Forward voltage and forward current within acceptable design margins

Substitute parts are grouped into two categories based on isolation voltage performance:

Category A - Full Isolation Voltage Match (5300Vrms): Parts maintaining the original 5300Vrms isolation specification: 4N27S (onsemi), 4N27XSM (Isocom)

Category B - Reduced Isolation Voltage (5000Vrms): Parts with 5000Vrms isolation, suitable for applications not requiring the full 5300Vrms specification: 4N27-X007 (Vishay), 4N27-X009T (Vishay), 4N27-X017T (Vishay)

Category C - Lower Isolation Voltage (1500Vrms): Parts with significantly reduced isolation voltage, applicable only to low-voltage isolation applications: 4N27S-TA (Lite-On), 4N27S-TA1 (Lite-On)

Category D - Non-Standard Isolation Specification: Part with alternative isolation specification: 4N27SMT&R (Isocom) - 7.5Vpk isolation

Parameter Comparison

Parameter	4N273S	4N27S	4N27XSM	4N27-X007	4N27-X009T	4N27-X017T	4N27S-TA	4N27S-TA1	4N27SMT&R
Manufacturer	onsemi	onsemi	Isocom	Vishay	Vishay	Vishay	Lite-On	Lite-On	Isocom
Number of Channels	1	1	1	1	1	1	1	1	1
Voltage - Isolation	5300Vrms	5300Vrms	5300Vrms	5000Vrms	5000Vrms	5000Vrms	1500Vrms	1500Vrms	7.5Vpk
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
Current Transfer Ratio (Min)	10% @ 10mA	10% @ 10mA	10% @ 10mA	10% @ 10mA	10% @ 10mA	10% @ 10mA	10% @ 10mA	10% @ 10mA	10% @ 10mA
Voltage - Output (Max)	30V	30V	30V	70V	70V	70V	30V	30V	30V
Current - Output / Channel	—	—	50mA	50mA	50mA	50mA	100mA	100mA	50mA
Voltage - Forward (Vf) (Typ)	1.18V	1.18V	1.2V	1.36V	1.36V	1.36V	1.2V	1.2V	1.2V
Current - DC Forward (If) (Max)	100 mA	100 mA	60 mA	60 mA	60 mA	60 mA	80 mA	80 mA	60 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
Input Type	DC	DC	DC	DC	DC	DC	DC	DC	DC
Product Status	Obsolete	Obsolete	Active	Active	Active	Active	Active	Active	Active
RoHS Status	—	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (5300Vrms Isolation Required):

4N27XSM (Isocom Components) is the primary substitute. It maintains identical isolation voltage (5300Vrms), output voltage (30V), and thermal range. Product status is Active with ROHS3 compliance. Packaging is Tube. Current inventory is 693 units.

4N27S (onsemi) provides equivalent electrical specifications but shares obsolete product status with the original part. Use only if existing supply chain relationships require onsemi sourcing.

For Applications Tolerating 5000Vrms Isolation:

4N27-X009T (Vishay Semiconductor Opto Division) offers the highest inventory availability (12,590 units) in Tape & Reel packaging. Isolation voltage is reduced to 5000Vrms, but output voltage capability increases to 70V. Product status is Active with ROHS3 compliance.

4N27-X017T (Vishay) provides identical electrical specifications to 4N27-X009T with 12,850 units in stock.

4N27-X007 (Vishay) is available in Tube packaging with 830 units in stock, offering the same 5000Vrms isolation and 70V output capability.

For Low-Voltage Isolation Applications (1500Vrms):

4N27S-TA and 4N27S-TA1 (Lite-On Inc.) are suitable only for applications where 1500Vrms isolation is sufficient. Both are Active products with ROHS3 compliance and offer higher output current (100mA) compared to the original part.

Not Recommended:

4N27SMT&R (Isocom) features non-standard 7.5Vpk isolation specification, incompatible with the original 5300Vrms requirement. Use only for specialized low-voltage applications.

Frequently Asked Questions (FAQ)

Q: Can 4N27-X009T replace 4N273S directly in my circuit?

A: 4N27-X009T is electrically compatible if your application does not require the full 5300Vrms isolation. The substitute provides 5000Vrms isolation, which is suitable for most industrial applications. Both parts share identical channel count, output type, current transfer ratio, and operating temperature range. Verify your circuit's isolation voltage requirement before substitution.

Q: What is the difference between Tape & Reel and Tube packaging?

A: Tape & Reel (TR) packaging is used for automated assembly lines and high-volume production. Tube packaging is used for manual assembly or lower-volume applications. Both contain the same component; packaging choice depends on manufacturing process requirements. 4N27-X009T and 4N27-X017T are supplied in Tape & Reel. 4N27-X007 and 4N27XSM are supplied in Tube.

Q: Why is 4N273S obsolete?

A: The original manufacturer (onsemi) has discontinued the 4N273S. Active substitutes from Vishay, Isocom, and Lite-On provide equivalent or superior functionality, making the original part unnecessary for new designs.

Q: Can I use 4N27S-TA if my application requires high isolation voltage?

A: No. 4N27S-TA provides only 1500Vrms isolation, significantly lower than the original 5300Vrms. Use this part only for low-voltage isolation applications. For high-isolation requirements, select 4N27XSM, 4N27-X009T, 4N27-X017T, or 4N27-X007.

Q: What is the difference between 4N27-X009T and 4N27-X017T?

A: Both parts are manufactured by Vishay and provide identical electrical specifications: 5000Vrms isolation, 70V output voltage, 50mA output current, and 500mV Vce saturation. The difference is in internal design variant (X009T vs. X017T). Both are Active products with ROHS3 compliance. Selection between them depends on availability and supplier preference.

Q: Is 4N27XSM a true equivalent to 4N273S?

A: Yes. 4N27XSM (Isocom) maintains the original 5300Vrms isolation voltage, 30V output voltage, and 500mV Vce saturation. It is an Active product with ROHS3 compliance. The primary difference is manufacturer (Isocom vs. onsemi) and packaging (Tube). Electrical performance is equivalent.

Q: What does "Current Transfer Ratio (Min): 10% @ 10mA" mean?

A: This specifies the minimum ratio of output current to input current at a 10mA input level. All listed substitutes meet or exceed this 10% minimum specification, ensuring consistent optical coupling efficiency.

Q: Can I mix different substitute parts in the same production batch?

A: All listed substitutes are pin-compatible and functionally equivalent within their isolation voltage class. However, mixing parts from different manufacturers may introduce minor variations in forward voltage and saturation characteristics. Verify circuit tolerance to these variations before mixing suppliers.

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