H11A2FM Optoisolator Equivalent & Substitute Parts

Part Overview

The H11A2FM is an optoisolator transistor with base output manufactured by onsemi, designed for high-voltage isolation applications. This component features a 7500Vpk isolation rating and operates as a single-channel optoisolator in a 6-SMD surface mount package. The H11A2FM is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. Substitute parts must maintain compatibility across isolation voltage, channel configuration, output type, and mounting characteristics.

Key Parameters

Parameter	H11A2FM
Manufacturer	onsemi
Product Status	Obsolete
Number of Channels	1
Voltage - Isolation	7500Vpk
Current Transfer Ratio (Min)	20% @ 10mA
Output Type	Transistor with Base
Voltage - Output (Max)	30V
Vce Saturation (Max)	400mV
Operating Temperature	-40°C ~ 100°C
Mounting Type	Surface Mount
Package / Case	6-SMD, Gull Wing

Substitute Part Grouping Explanation

Substitution for the H11A2FM is determined by the following critical parameters:

Number of Channels: Must be 1 channel
Output Type: Must be Transistor with Base
Voltage - Isolation: Minimum 7500Vpk (or equivalent Vrms rating)
Current Transfer Ratio: Minimum 20% @ 10mA
Voltage - Output (Max): 30V or greater
Operating Temperature Range: Must encompass -40°C to 100°C
Input Type: DC

The substitute parts identified are 4N25SR2M and H11A2X. The 4N25SR2M maintains surface mount compatibility with reduced isolation voltage (4170Vrms), while the H11A2X provides through-hole mounting with intermediate isolation voltage (5300Vrms). Both alternatives meet the core functional requirements of single-channel transistor output with base connection and equivalent current transfer characteristics.

Parameter Comparison

Parameter	H11A2FM	4N25SR2M	H11A2X
Manufacturer	onsemi	onsemi	Isocom Components
Product Status	Obsolete	Active	Active
Number of Channels	1	1	1
Voltage - Isolation	7500Vpk	4170Vrms	5300Vrms
Current Transfer Ratio (Min)	20% @ 10mA	20% @ 10mA	20% @ 10mA
Turn On / Turn Off Time (Typ)	2µs, 2µs	2µs, 2µs	—
Input Type	DC	DC	DC
Output Type	Transistor with Base	Transistor with Base	Transistor with Base
Voltage - Output (Max)	30V	30V	30V
Voltage - Forward (Vf) (Typ)	1.18V	1.18V	1.2V
Current - DC Forward (If) (Max)	60 mA	60 mA	60 mA
Vce Saturation (Max)	400mV	500mV	400mV
Operating Temperature	-40°C ~ 100°C	-40°C ~ 100°C	-55°C ~ 100°C
Mounting Type	Surface Mount	Surface Mount	Through Hole
Package / Case	6-SMD, Gull Wing	6-SMD, Gull Wing	6-DIP (0.300", 7.62mm)
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

4N25SR2M (onsemi): This substitute maintains identical surface mount packaging (6-SMD, Gull Wing) and is currently in active production status. It is ROHS3 compliant and carries the same REACH unaffected designation. The primary trade-off is reduced isolation voltage (4170Vrms versus 7500Vpk). Selection of this part is appropriate for applications where the lower isolation rating is acceptable and surface mount assembly is required.

H11A2X (Isocom Components): This substitute provides intermediate isolation voltage (5300Vrms) and is also in active production with ROHS3 compliance. The mounting type transitions to through-hole (6-DIP), requiring PCB redesign. The operating temperature range extends to -55°C, providing broader low-temperature capability. Selection of this part is appropriate for applications requiring through-hole assembly or extended low-temperature operation where the isolation voltage requirement can be met at 5300Vrms.

Both substitutes maintain the critical functional parameters: single-channel configuration, transistor output with base connection, 20% minimum current transfer ratio, and 30V maximum output voltage.

Frequently Asked Questions (FAQ)

Q: Can the 4N25SR2M directly replace the H11A2FM in existing designs?

A: Direct replacement is possible if the application isolation voltage requirement does not exceed 4170Vrms. The 4N25SR2M maintains identical surface mount packaging and electrical characteristics (current transfer ratio, output voltage, saturation voltage). PCB layout modifications are not required. Verify that your isolation voltage specification can be met at the lower rating.

Q: What is the primary difference between the H11A2X and H11A2FM?

A: The H11A2X differs in three aspects: mounting type (through-hole 6-DIP versus surface mount 6-SMD), isolation voltage (5300Vrms versus 7500Vpk), and operating temperature range (-55°C to 100°C versus -40°C to 100°C). PCB redesign is necessary to accommodate the through-hole package.

Q: Are both substitute parts RoHS compliant?

A: Yes. Both 4N25SR2M and H11A2X are ROHS3 compliant. The original H11A2FM RoHS status is not specified in the available data.

Q: Which substitute should I select if isolation voltage is critical?

A: If your application requires isolation voltage at or above 7500Vpk, neither substitute fully meets this specification. The H11A2X provides the highest isolation among the substitutes at 5300Vrms. Evaluate whether your actual isolation requirement can be satisfied at this level, or consider alternative optoisolator families with higher voltage ratings.

Q: Can I use the H11A2X in a surface mount assembly?

A: No. The H11A2X is a through-hole component (6-DIP package). Surface mount assembly requires either the H11A2FM or 4N25SR2M, both available in 6-SMD surface mount packages.

Q: What is the impact of the 500mV Vce saturation in the 4N25SR2M versus 400mV in the H11A2FM?

A: The 4N25SR2M has a 100mV higher saturation voltage. This results in slightly higher power dissipation in the output transistor. For most applications, this difference is negligible. Verify saturation voltage specifications against your circuit design requirements if output transistor power dissipation is a critical parameter.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message