IRLZ44STRL N-Channel MOSFET 60V 50A D2PAK Equivalent & Substitute Parts

Part Overview

The IRLZ44STRL is an N-Channel metal oxide semiconductor field-effect transistor (MOSFET) manufactured by Vishay Siliconix, rated for 60V drain-to-source voltage and 50A continuous drain current in a surface mount TO-263 (D2PAK) package. This device is classified as obsolete, which necessitates identification of equivalent and substitute parts for ongoing design support and procurement continuity. The IRLZ44STRL serves in applications requiring moderate voltage and high current switching capability with low on-state resistance characteristics.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	60	V
Continuous Drain Current (Id) @ 25°C	50	A (Tc)
On-State Resistance (Rds On Max) @ 31A, 5V	28	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	2	V
Gate Charge (Qg) @ 5V	66	nC
Input Capacitance (Ciss) @ 25V	3300	pF
Power Dissipation (Max)	3.7 (Ta), 150 (Tc)	W
Operating Temperature Range	-55 to 175	°C (TJ)
Package Type	TO-263 (D2PAK)	Surface Mount
FET Technology	Metal Oxide	N-Channel

Substitute Part Grouping Explanation

Substitution of the IRLZ44STRL is determined by electrical and mechanical compatibility across the following critical parameters:

Primary Substitution Criteria:

Drain-to-Source Voltage (Vdss): Minimum 60V required for direct substitution
Continuous Drain Current (Id): Minimum 50A required to maintain current handling capability
On-State Resistance (Rds On): Maximum 28mOhm at specified gate voltage to preserve switching efficiency
Package Type: TO-263 (D2PAK) surface mount configuration mandatory for mechanical compatibility
Operating Temperature Range: -55°C to 175°C (TJ) minimum required
Gate Threshold Voltage (Vgs(th)): 2V maximum for consistent gate drive compatibility

Substitution Categories:

Category 1: Direct Parametric Equivalents – Parts meeting or exceeding all primary electrical specifications with identical package type and active product status.

Category 2: Parametric Equivalents with Reduced Ratings – Parts with lower voltage or current ratings but compatible package and operating characteristics, suitable for applications not requiring full rated specifications.

Category 3: Packaging Variants – Identical electrical specifications with alternative packaging formats (Tube, Tape & Reel) from the same manufacturer base product line.

Parameter Comparison

Parameter	IRLZ44STRL (Main)	IRLZ44SPBF	IRLZ44STRRPBF	BUK9635-55A,118	IRLZ44NSTRLPBF	IRLZ44ZSTRLPBF
Manufacturer	Vishay Siliconix	Vishay Siliconix	Vishay Siliconix	Nexperia USA Inc.	Infineon Technologies	Infineon Technologies
Vdss (V)	60	60	60	55	55	55
Id @ 25°C (A)	50	50	50	34	47	51
Rds On Max (mOhm)	28 @ 31A, 5V	28 @ 31A, 5V	28 @ 31A, 5V	32 @ 25A, 10V	22 @ 25A, 10V	13.5 @ 31A, 10V
Vgs(th) Max (V)	2 @ 250µA	2 @ 250µA	2 @ 250µA	2 @ 1mA	2 @ 250µA	3 @ 250µA
Qg @ 5V (nC)	66	66	66	—	48	36
Ciss @ 25V (pF)	3300	3300	3300	1173	1700	1620
Power Dissipation (W)	3.7 (Ta), 150 (Tc)	3.7 (Ta), 150 (Tc)	3.7 (Ta), 150 (Tc)	85 (Tc)	3.8 (Ta), 110 (Tc)	80 (Tc)
Operating Temp (°C)	-55 to 175	-55 to 175	-55 to 175	-55 to 175	-55 to 175	-55 to 175
Package	TO-263 (D2PAK)	TO-263 (D2PAK)	TO-263 (D2PAK)	D2PAK	D2PAK	D2PAK
Product Status	Obsolete	Active	Active	Active	Not For New Designs	Obsolete
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging Format	—	Tube	Tape & Reel (TR)	Tape & Reel (TR)	Cut Tape (CT) & Digi-Reel®	Cut Tape (CT)

Engineering Selection Recommendations

IRLZ44SPBF (Recommended Primary Substitute)

The IRLZ44SPBF is the manufacturer-recommended substitute for the obsolete IRLZ44STRL. This part maintains identical electrical specifications across all critical parameters: 60V Vdss, 50A continuous drain current, and 28mOhm on-state resistance. The device is manufactured by Vishay Siliconix and carries active product status with ROHS3 compliance. The primary distinction is packaging format (Tube versus unspecified original packaging). This part is suitable for direct replacement in existing designs without circuit modification.

IRLZ44STRRPBF (Recommended Primary Substitute – Tape & Reel Format)

The IRLZ44STRRPBF provides identical electrical performance to the IRLZ44STRL with active product status and ROHS3 compliance. This variant is supplied in Tape & Reel (TR) format, appropriate for high-volume manufacturing environments. Electrical specifications are fully equivalent: 60V Vdss, 50A Id, and 28mOhm Rds On. This part is suitable for direct replacement in existing designs without circuit modification.

BUK9635-55A,118 (Parametric Equivalent – Reduced Ratings)

The BUK9635-55A,118 from Nexperia USA Inc. operates at reduced voltage (55V Vdss) and current (34A Id) specifications compared to the IRLZ44STRL. This part is suitable only for applications where the full 60V/50A ratings are not required. The device carries active product status, ROHS3 compliance, and AEC-Q101 automotive qualification. On-state resistance is 32mOhm at 25A, 10V, which is acceptable for lower-current applications. Package type is D2PAK, maintaining mechanical compatibility.

IRLZ44NSTRLPBF (Parametric Equivalent – Reduced Voltage)

The IRLZ44NSTRLPBF from Infineon Technologies operates at 55V Vdss with 47A continuous drain current. This part is classified as "Not For New Designs" and carries ROHS3 compliance. On-state resistance is 22mOhm at 25A, 10V, providing superior switching efficiency compared to the main part. This device is suitable for applications not requiring the full 60V rating. The lower gate charge (48nC) and reduced input capacitance (1700pF) may provide improved switching speed in gate-drive-limited applications.

IRLZ44ZSTRLPBF (Parametric Equivalent – Enhanced Performance)

The IRLZ44ZSTRLPBF from Infineon Technologies operates at 55V Vdss with 51A continuous drain current, exceeding the main part's current rating. This part is classified as obsolete with ROHS3 compliance. On-state resistance is significantly lower at 13.5mOhm at 31A, 10V, providing superior efficiency. Gate charge is reduced to 36nC, and input capacitance is 1620pF. This device is suitable for applications where the 55V rating is acceptable and enhanced switching performance is beneficial.

Compliance Considerations:

The IRLZ44STRL is RoHS non-compliant. All recommended substitutes (IRLZ44SPBF, IRLZ44STRRPBF, BUK9635-55A,118, IRLZ44NSTRLPBF, IRLZ44ZSTRLPBF) are ROHS3 compliant, supporting regulatory requirements for new designs and manufacturing environments with RoHS mandates.

Frequently Asked Questions (FAQ)

Q: Can IRLZ44SPBF be used as a direct replacement for IRLZ44STRL without circuit modification?

A: Yes. The IRLZ44SPBF maintains identical electrical specifications: 60V Vdss, 50A continuous drain current, 28mOhm on-state resistance, and 2V gate threshold voltage. The only difference is packaging format (Tube). No circuit modification is required.

Q: What is the difference between IRLZ44STRRPBF and IRLZ44SPBF?

A: Both parts are electrically identical with 60V Vdss and 50A Id ratings. The primary difference is packaging format: IRLZ44STRRPBF is supplied in Tape & Reel (TR) format for automated assembly, while IRLZ44SPBF is supplied in Tube format. Selection depends on manufacturing process requirements.

Q: Can BUK9635-55A,118 replace IRLZ44STRL in all applications?

A: No. The BUK9635-55A,118 has reduced voltage (55V versus 60V) and current (34A versus 50A) ratings. This part is suitable only for applications where the full 60V/50A specifications are not required. Verify application requirements before substitution.

Q: Why is IRLZ44NSTRLPBF marked "Not For New Designs"?

A: This designation indicates the part is in the later stages of its product lifecycle. While the part remains available and functional, Infineon recommends using alternative parts for new design projects. For existing designs requiring this part, continued availability is supported.

Q: What is the significance of the D2PAK package designation?

A: D2PAK (also designated TO-263) is a surface mount package with three leads: Drain, Gate, and Source (with Source connected to the tab). All substitute parts listed maintain this package type, ensuring mechanical and thermal compatibility with existing PCB layouts and thermal management designs.

Q: How does on-state resistance (Rds On) affect device selection?

A: On-state resistance determines power dissipation during switching operation. Lower Rds On values reduce heat generation and improve efficiency. The IRLZ44STRL specifies 28mOhm at 31A, 5V. Substitutes with lower Rds On (such as IRLZ44ZSTRLPBF at 13.5mOhm) provide improved efficiency but may have different gate drive requirements. Substitutes with higher Rds On increase power dissipation and may require enhanced thermal management.

Q: Are all substitute parts RoHS compliant?

A: Yes. All recommended substitutes carry ROHS3 compliance status. The original IRLZ44STRL is RoHS non-compliant. Substitution to any recommended part satisfies RoHS regulatory requirements for manufacturing environments with RoHS mandates.

Q: What is the impact of gate charge (Qg) differences on circuit design?

A: Gate charge affects gate drive circuit design and switching speed. The IRLZ44STRL specifies 66nC at 5V. Substitutes with lower gate charge (IRLZ44NSTRLPBF at 48nC, IRLZ44ZSTRLPBF at 36nC) require less gate drive energy and may switch faster. Verify gate drive circuit capability before substitution if gate charge differs significantly.

Q: Can IRLZ44ZSTRLPBF be used in place of IRLZ44STRL despite obsolete status?

A: The IRLZ44ZSTRLPBF is electrically superior with lower on-state resistance and gate charge, but operates at 55V Vdss versus the original 60V. This part is suitable only if the application does not require the full 60V rating. Both parts are obsolete; IRLZ44SPBF or IRLZ44STRRPBF are preferred for new designs due to active product status.

Q: What thermal considerations apply when substituting parts with different power dissipation ratings?

A: Power dissipation specifications are provided for reference. Actual dissipation depends on application current, switching frequency, and duty cycle. Parts with lower on-state resistance (such as IRLZ44ZSTRLPBF at 13.5mOhm) generate less heat than the original (28mOhm), potentially reducing thermal management requirements. Verify thermal design margins for substitutes with higher on-state resistance values.

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