MPSW3725 Equivalent & Substitute Parts

Part Overview

The MPSW3725 is an NPN bipolar junction transistor manufactured by onsemi, rated for 40 V collector-emitter breakdown voltage and 1.2 A maximum collector current. This device is packaged in TO-226-3 (TO-92-3) configuration and is designed for through-hole mounting applications requiring 1 W power dissipation capability.

The MPSW3725 is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for new production runs, repairs, and system upgrades where the original part is no longer readily available from primary sources.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	40	V
Current - Collector (Ic) (Max)	1.2	A
Power - Max	1	W
Frequency - Transition	250	MHz
Operating Temperature Range	-55 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-226-3 / TO-92-3	—

Substitute Part Grouping Explanation

Substitution of the MPSW3725 is determined by the following critical parameters:

Mandatory Compatibility Criteria:

Transistor Type: NPN (must match)
Mounting Type: Through Hole (must match)
Package Compatibility: TO-92-3 or E-Line (TO-92 compatible) configurations
Voltage - Collector Emitter Breakdown: Must equal or exceed 40 V
Current - Collector (Ic) (Max): Must equal or exceed 1.2 A
Power - Max: Must equal or exceed 1 W
Operating Temperature Range: Must encompass or exceed -55°C to 150°C

Secondary Considerations:

Frequency - Transition: Higher values indicate improved high-frequency performance
DC Current Gain (hFE): Higher values indicate improved amplification characteristics
Vce Saturation: Lower values indicate improved switching efficiency

The substitute parts listed below satisfy all mandatory compatibility criteria and are therefore electrically and mechanically interchangeable with the MPSW3725 in standard circuit applications.

Parameter Comparison

Parameter	MPSW3725	ZTX450	ZTX690B	ZTX1051A	Unit
Manufacturer	onsemi	Diodes Incorporated	Diodes Incorporated	Diodes Incorporated	—
Transistor Type	NPN	NPN	NPN	NPN	—
Voltage - Collector Emitter Breakdown (Max)	40	45	45	40	V
Current - Collector (Ic) (Max)	1.2	1	2	4	A
Vce Saturation (Max)	950 @ 100mA, 1A	250 @ 15mA, 150mA	500 @ 5mA, 1A	210 @ 100mA, 4A	mV
Current - Collector Cutoff (Max)	100	100	100	10	nA
DC Current Gain (hFE) (Min)	60 @ 100mA, 1V	100 @ 150mA, 10V	400 @ 1A, 2V	300 @ 1A, 2V	—
Power - Max	1	1	1	1	W
Frequency - Transition	250	150	150	155	MHz
Operating Temperature Range	-55 to 150	-55 to 200	-55 to 200	-55 to 200	°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	—
Package / Case	TO-226-3 / TO-92-3	E-Line-3 (TO-92 compatible)	E-Line-3 (TO-92 compatible)	E-Line-3 (TO-92 compatible)	—
Product Status	Obsolete	Active	Active	Active	—
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

ZTX450 (Diodes Incorporated)

The ZTX450 is an active product with ROHS3 compliance. It meets the mandatory voltage requirement (45 V exceeds 40 V specification) and provides equivalent current handling at 1 A. The extended operating temperature range (-55°C to 200°C) exceeds the MPSW3725 requirement. Package compatibility is confirmed through E-Line (TO-92 compatible) configuration. This part is suitable for applications where the collector current requirement does not exceed 1 A.

ZTX690B (Diodes Incorporated)

The ZTX690B is an active product with ROHS3 compliance. It exceeds the mandatory voltage requirement (45 V) and provides enhanced current handling capability at 2 A, which accommodates the 1.2 A requirement with margin. The extended operating temperature range (-55°C to 200°C) exceeds the MPSW3725 requirement. Package compatibility is confirmed through E-Line (TO-92 compatible) configuration. This part is suitable for applications requiring improved current capacity and switching efficiency, as evidenced by lower Vce saturation voltage.

ZTX1051A (Diodes Incorporated)

The ZTX1051A is an active product with ROHS3 compliance. It meets the mandatory voltage requirement (40 V matches specification) and provides superior current handling capability at 4 A, which significantly exceeds the 1.2 A requirement. The extended operating temperature range (-55°C to 200°C) exceeds the MPSW3725 requirement. Package compatibility is confirmed through E-Line (TO-92 compatible) configuration. This part is suitable for applications requiring maximum current capacity and improved DC current gain characteristics.

All three substitute parts are manufactured by Diodes Incorporated, an active supplier with current production status and regulatory compliance certifications. Selection among these alternatives depends on specific application current requirements and performance optimization objectives.

Frequently Asked Questions (FAQ)

Q: Can the ZTX450 directly replace the MPSW3725 in all applications?

A: The ZTX450 is electrically compatible with the MPSW3725 for applications where collector current does not exceed 1 A. Both devices share identical 1 W power dissipation and through-hole mounting characteristics. The ZTX450 provides higher voltage rating (45 V vs. 40 V) and extended temperature range. Physical package compatibility is confirmed through E-Line (TO-92 compatible) configuration, which is mechanically equivalent to TO-226-3 / TO-92-3.

Q: What is the primary advantage of the ZTX690B over the MPSW3725?

A: The ZTX690B provides doubled collector current capacity (2 A vs. 1.2 A) while maintaining identical power dissipation (1 W) and voltage rating (45 V exceeds 40 V). The ZTX690B exhibits significantly lower Vce saturation voltage (500 mV vs. 950 mV at comparable current levels), resulting in improved switching efficiency and reduced power loss during saturation. Both devices are through-hole mounted and mechanically compatible.

Q: Is the ZTX1051A suitable for high-current applications?

A: The ZTX1051A is rated for 4 A maximum collector current, which substantially exceeds the MPSW3725 specification of 1.2 A. This device is suitable for applications requiring enhanced current handling capability. The ZTX1051A maintains 1 W power dissipation and 40 V voltage rating compatibility. The device exhibits superior DC current gain (300 minimum vs. 60 minimum) and lower collector cutoff current (10 nA vs. 100 nA), indicating improved amplification characteristics and reduced leakage.

Q: Are all substitute parts RoHS compliant?

A: Yes. The ZTX450, ZTX690B, and ZTX1051A are all ROHS3 compliant. The MPSW3725 RoHS status is not specified in the provided documentation. All substitute parts carry REACH Unaffected designation and EAR99 ECCN classification, matching the MPSW3725 regulatory profile.

Q: What is the difference between TO-226-3 and E-Line (TO-92 compatible) packaging?

A: TO-226-3 and E-Line (TO-92 compatible) are mechanically equivalent three-lead through-hole packages. Both configurations provide identical pin spacing and mounting hole compatibility for standard PCB layouts. The E-Line designation indicates Diodes Incorporated's proprietary package variant, which maintains full mechanical and electrical compatibility with TO-92-3 standard configurations.

Q: Can the MPSW3725 be used in new production designs?

A: The MPSW3725 is classified as obsolete and is not recommended for new production designs. Active substitute parts (ZTX450, ZTX690B, ZTX1051A) are available from Diodes Incorporated with confirmed current production status, regulatory compliance, and long-term supply availability. New designs should incorporate one of the active substitute parts to ensure component availability and supply chain continuity.

Q: Which substitute part provides the best frequency performance?

A: The MPSW3725 provides the highest transition frequency at 250 MHz. The substitute parts operate at lower transition frequencies: ZTX450 and ZTX690B at 150 MHz, and ZTX1051A at 155 MHz. For applications requiring maximum high-frequency performance, the MPSW3725 characteristics exceed all listed substitutes. However, for standard switching and amplification applications operating below 150 MHz, the substitute parts provide adequate frequency response.

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