IRF644 N-Channel MOSFET 250V 14A Equivalent & Substitute Parts

Part Overview

The IRF644 is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 250V drain-to-source voltage with 14A continuous drain current at 25°C. The device is housed in a TO-220AB through-hole package and is rated for 125W maximum power dissipation. The IRF644 is classified as obsolete, making identification of active equivalent and substitute parts essential for ongoing design support and procurement continuity. Substitute parts must maintain electrical and mechanical compatibility while meeting current manufacturing and compliance standards.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	250	V
Continuous Drain Current (Id) @ 25°C	14	A
Drive Voltage (Max Rds On)	10	V
Rds On (Max) @ Id, Vgs	280 mOhm @ 8.4A, 10V	—
Gate Threshold Voltage (Vgs(th)) @ Id	4	V @ 250µA
Gate Charge (Qg) @ Vgs	68	nC @ 10V
Maximum Gate Voltage (Vgs)	±20	V
Input Capacitance (Ciss) @ Vds	1300	pF @ 25V
Power Dissipation (Max)	125	W
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—

Substitute Part Grouping Explanation

Substitute parts for the IRF644 are selected based on strict electrical and mechanical parameter matching. The primary substitution criteria are:

Critical Matching Parameters:

Drain-to-Source Voltage (Vdss): 250V minimum
FET Type: N-Channel
Mounting Type: Through Hole
Package: TO-220 or TO-220AB compatible
Operating Temperature Range: -55°C to 150°C minimum
Gate Voltage Rating (Vgs): ±20V

Secondary Compatibility Parameters:

Continuous Drain Current (Id): Equal to or greater than 14A
Drive Voltage: 10V gate drive compatibility
Gate Threshold Voltage (Vgs(th)): Within 3.5V to 4V range
Maximum Gate Charge (Qg): Lower values indicate improved switching performance

Substitute parts are grouped into two categories: direct equivalents (identical electrical specifications) and functional substitutes (superior or equivalent performance within the same voltage and current class).

Parameter Comparison

Parameter	IRF644	IRF644PBF	STP17NF25	TK13E25D,S1X(S
Manufacturer	Vishay Siliconix	Vishay Siliconix	STMicroelectronics	Toshiba Semiconductor
Product Status	Obsolete	Active	Active	Active
Vdss (V)	250	250	250	250
Id @ 25°C (A)	14	14	17	13
Rds On (Max) @ 10V (mOhm)	280 @ 8.4A	280 @ 8.4A	165 @ 8.5A	250 @ 6.5A
Vgs(th) (V)	4 @ 250µA	4 @ 250µA	4 @ 250µA	3.5 @ 1mA
Gate Charge Qg (nC @ 10V)	68	68	29.5	25
Ciss (pF)	1300 @ 25V	1300 @ 25V	1000 @ 25V	1100 @ 100V
Power Dissipation (Max) (W)	125	125	90	102
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package	TO-220AB	TO-220AB	TO-220	TO-220-3
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

IRF644PBF (Direct Equivalent)

The IRF644PBF is the active production equivalent of the IRF644. It maintains identical electrical specifications including 250V Vdss, 14A continuous drain current, 280mOhm Rds(on), and 125W power dissipation. The IRF644PBF is ROHS3 compliant and carries active product status, making it the primary replacement for obsolete IRF644 units. Packaging is supplied in tube format. This part is suitable for direct substitution in all applications where the IRF644 was originally specified.

STP17NF25 (Functional Substitute)

The STP17NF25 from STMicroelectronics is a functional substitute offering superior electrical performance. It maintains the 250V Vdss rating and exceeds the current requirement with 17A continuous drain current. The STP17NF25 features significantly lower Rds(on) at 165mOhm (versus 280mOhm), resulting in reduced power dissipation and improved thermal efficiency. Gate charge is reduced to 29.5nC, enabling faster switching characteristics. The device is ROHS3 compliant and carries active product status. The TO-220 package is mechanically compatible with TO-220AB footprints. This substitute is applicable in applications where improved efficiency and thermal performance are beneficial.

TK13E25D,S1X(S (Functional Substitute)

The TK13E25D,S1X(S from Toshiba Semiconductor is a functional substitute with 250V Vdss rating and 13A continuous drain current, slightly below the IRF644 specification. The device features 250mOhm Rds(on) and reduced gate charge of 25nC, supporting faster switching operation. Power dissipation is rated at 102W. The TK13E25D,S1X(S is ROHS3 compliant and carries active product status. The TO-220-3 package is mechanically compatible with the IRF644 footprint. This substitute is suitable for applications where the 13A current rating is sufficient and lower gate charge is advantageous.

Frequently Asked Questions (FAQ)

Q: Can the IRF644PBF be used as a direct replacement for the IRF644?

A: Yes. The IRF644PBF is electrically and mechanically identical to the IRF644, with matching Vdss (250V), Id (14A), Rds(on) (280mOhm), and power dissipation (125W). The primary difference is product status: IRF644PBF is active production while IRF644 is obsolete. IRF644PBF is ROHS3 compliant, whereas the original IRF644 is non-compliant.

Q: What are the advantages of using STP17NF25 over IRF644PBF?

A: The STP17NF25 offers superior performance characteristics: 17A continuous drain current (versus 14A), significantly lower Rds(on) at 165mOhm (versus 280mOhm), and reduced gate charge at 29.5nC (versus 68nC). These improvements result in lower power dissipation, reduced thermal load, and faster switching response. The trade-off is slightly lower maximum power dissipation rating (90W versus 125W).

Q: Are all substitute parts compatible with the original TO-220AB footprint?

A: Yes. All substitute parts use TO-220 or TO-220-3 packages, which are mechanically and electrically compatible with the TO-220AB footprint. Pin configuration and lead spacing are identical across these package variants.

Q: What is the minimum continuous drain current requirement for a valid substitute?

A: A valid substitute must support a continuous drain current equal to or greater than 14A at 25°C. The STP17NF25 (17A) and TK13E25D,S1X(S (13A) both meet or approach this requirement. The TK13E25D,S1X(S at 13A is marginally below specification and should be evaluated for specific application current demands.

Q: Are all substitute parts RoHS compliant?

A: The IRF644PBF, STP17NF25, and TK13E25D,S1X(S are all ROHS3 compliant. The original IRF644 is RoHS non-compliant. For applications requiring RoHS compliance, only the three active substitutes are acceptable.

Q: What is the significance of gate charge (Qg) differences between parts?

A: Gate charge determines the energy required to switch the MOSFET on and off. Lower gate charge (STP17NF25 at 29.5nC, TK13E25D,S1X(S at 25nC) enables faster switching transitions and reduced driver power consumption compared to the IRF644 and IRF644PBF (both 68nC). This is particularly important in high-frequency switching applications.

Q: Can the TK13E25D,S1X(S be used in all IRF644 applications?

A: The TK13E25D,S1X(S is suitable for applications where the 13A continuous drain current rating is sufficient. Applications requiring the full 14A specification should use IRF644PBF or STP17NF25. Verify application current demands before selecting this substitute.

Q: What is the operating temperature range for all substitute parts?

A: All substitute parts, including IRF644PBF, STP17NF25, and TK13E25D,S1X(S, support the full operating temperature range of -55°C to 150°C (TJ), matching the original IRF644 specification.

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