MCT271M Optoisolator Equivalent & Substitute Parts

Part Overview

The MCT271M is a 7500Vpk isolation voltage optoisolator transistor with base output manufactured by onsemi in a 6-DIP package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The MCT271M provides single-channel isolation with 45-90% current transfer ratio and 50mA output current capability, suitable for high-voltage isolation applications requiring through-hole mounting.

Key Parameters

Parameter	Value
Manufacturer Part Number	MCT271M
Manufacturer	onsemi
Category	Optoisolators
Package / Case	6-DIP (0.300", 7.62mm)
Number of Channels	1
Voltage - Isolation	7500Vpk
Current Transfer Ratio (Min)	45% @ 10mA
Current Transfer Ratio (Max)	90% @ 10mA
Output Type	Transistor with Base
Voltage - Output (Max)	30V
Current - Output / Channel	50mA
Operating Temperature	-40°C ~ 100°C
Mounting Type	Through Hole
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the MCT271M optoisolator is determined by the following critical parameters:

Primary Compatibility Criteria:

Package type: 6-DIP (0.300", 7.62mm) through-hole mounting
Output configuration: Transistor with base
Number of channels: Single channel (1)
Operating temperature range: -40°C to 100°C
Output current capability: 50mA per channel
Maximum output voltage: 30V or higher

Isolation Voltage Consideration: The MCT271M specifies 7500Vpk isolation. Substitute parts must maintain isolation voltage at or above this level to preserve circuit safety margins and regulatory compliance.

Current Transfer Ratio: The MCT271M operates with 45-90% CTR @ 10mA. Substitute parts with lower minimum CTR values require circuit design verification to ensure adequate signal transfer in the application.

Two substitute parts meet the core mechanical and electrical compatibility requirements: CNY171M and MCT2EM.

Parameter Comparison

Parameter	MCT271M	CNY171M	MCT2EM
Manufacturer	onsemi	onsemi	onsemi
Package / Case	6-DIP (0.300", 7.62mm)	6-DIP (0.300", 7.62mm)	6-DIP (0.300", 7.62mm)
Number of Channels	1	1	1
Voltage - Isolation	7500Vpk	4170Vrms	7500Vpk
Current Transfer Ratio (Min)	45% @ 10mA	40% @ 10mA	20% @ 10mA
Current Transfer Ratio (Max)	90% @ 10mA	80% @ 10mA	Not specified
Turn On / Turn Off Time (Typ)	1µs, 48µs	2µs, 3µs	2µs, 2µs
Output Type	Transistor with Base	Transistor with Base	Transistor with Base
Voltage - Output (Max)	30V	70V	30V
Current - Output / Channel	50mA	50mA	50mA
Vce Saturation (Max)	400mV	400mV	400mV
Operating Temperature	-40°C ~ 100°C	-40°C ~ 100°C	-40°C ~ 100°C
Mounting Type	Through Hole	Through Hole	Through Hole
Product Status	Obsolete	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

MCT2EM is the primary substitute for MCT271M. Both parts share identical isolation voltage (7500Vpk), maximum output voltage (30V), and output current (50mA). MCT2EM is currently in active production status with ROHS3 compliance certification. The minimum current transfer ratio of MCT2EM is 20% @ 10mA, which is lower than MCT271M's 45% minimum. Circuit designs relying on the higher CTR specification of MCT271M must account for this difference in signal transfer calculations.

CNY171M is an alternative substitute with active product status and ROHS3 compliance. However, CNY171M specifies 4170Vrms isolation voltage, which is lower than the MCT271M's 7500Vpk specification. CNY171M provides higher maximum output voltage (70V) and comparable current transfer ratio (40-80% @ 10mA). This part is suitable only for applications where the reduced isolation voltage meets circuit requirements.

Both substitute parts are manufactured by onsemi, use identical 6-DIP through-hole packaging, and operate across the same temperature range as the MCT271M.

Frequently Asked Questions (FAQ)

Q: Can MCT2EM directly replace MCT271M in existing designs?

A: MCT2EM shares the same package, isolation voltage, output voltage, and output current specifications as MCT271M. The primary design consideration is the lower minimum current transfer ratio (20% vs. 45%). Verify that circuit biasing and signal detection thresholds accommodate this difference before substitution.

Q: Why is CNY171M listed as a substitute if it has lower isolation voltage?

A: CNY171M meets the mechanical compatibility requirements (6-DIP package, through-hole mounting, single channel, 50mA output) and operates within the same temperature range. The 4170Vrms isolation is lower than MCT271M's 7500Vpk specification. CNY171M is suitable only for applications where isolation voltage requirements are 4170Vrms or lower.

Q: What is the difference between Vpk and Vrms isolation voltage specifications?

A: Vpk (peak voltage) and Vrms (RMS voltage) are different measurement standards for isolation voltage. Direct comparison requires conversion. CNY171M's 4170Vrms is approximately equivalent to 5900Vpk, which is lower than MCT271M's 7500Vpk specification.

Q: Are both substitute parts RoHS compliant?

A: Yes. Both MCT2EM and CNY171M are ROHS3 compliant. MCT271M's RoHS status is not specified in the available documentation.

Q: What are the packaging differences between these parts?

A: All three parts use identical 6-DIP (0.300", 7.62mm) through-hole packages. MCT271M is supplied in standard packaging, while CNY171M and MCT2EM are supplied in tube packaging. This difference does not affect electrical compatibility or board-level integration.

Q: Which substitute should I choose for new designs?

A: MCT2EM is the recommended choice for new designs due to matching isolation voltage (7500Vpk) and active product status. CNY171M is suitable only if your application's isolation voltage requirement is 4170Vrms or lower.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message