APT37F50B N-Channel 500V 37A MOSFET Equivalent & Substitute Parts

Part Overview

The APT37F50B is an N-Channel 500V 37A MOSFET manufactured by Microchip Technology in TO-247 [B] through-hole packaging. This device is rated for 520W power dissipation and operates across the temperature range of -55°C to 150°C. The part is currently in active product status with RoHS3 compliance and unlimited moisture sensitivity level (MSL 1).

Equivalent and substitute parts are identified based on matching or compatible electrical and mechanical parameters within the N-Channel MOSFET 500V category. Substitutes are selected when drain-source voltage, continuous drain current, gate charge characteristics, and through-hole packaging compatibility align with application requirements.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	500	V
Continuous Drain Current (Id) @ 25°C	37	A (Tc)
On-State Resistance (Rds On Max) @ 18A, 10V	150	mOhm
Gate Threshold Voltage (Vgs(th) Max) @ 1mA	5	V
Gate Charge (Qg Max) @ 10V	145	nC
Power Dissipation (Max)	520	W (Tc)
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-247-3	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution logic for the APT37F50B is based on the following critical parameters:

Primary Matching Criteria:

Drain to Source Voltage (Vdss): 500V (exact match required)
FET Type: N-Channel (exact match required)
Technology: MOSFET Metal Oxide (exact match required)
Mounting Type: Through Hole (exact match required)
Package Family: TO-247 variants (TO-247-3, TO-247AD, ISOPLUS247™, PLUS247™-3)

Secondary Compatibility Criteria:

Continuous Drain Current (Id): 25A to 46A range (application-dependent selection)
On-State Resistance (Rds On): 145mOhm to 200mOhm (performance trade-off consideration)
Gate Charge (Qg): 60nC to 260nC (switching speed and drive circuit compatibility)
Power Dissipation: 300W to 830W (thermal management dependent)
Operating Temperature: -55°C to 150°C (standard industrial range)

Compliance Requirements:

RoHS3 Compliant (all substitutes meet this requirement)
MSL 1 (Unlimited moisture sensitivity)
REACH Unaffected status

Substitutes are grouped by current rating proximity and on-state resistance characteristics. Parts with continuous drain current between 30A and 46A are considered direct functional alternatives when Vdss, package family, and compliance specifications match.

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On Max (mOhm)	Qg Max (nC)	Power Dissipation (W)	Package	Product Status
APT37F50B	Microchip Technology	500	37	150	145	520	TO-247 [B]	Active
IXFH36N50P	IXYS	500	36	170	93	540	TO-247AD	Active
IXFH34N50P3	IXYS	500	34	170	60	695	TO-247AD	Active
IXFH42N50P2	IXYS	500	42	145	92	830	TO-247AD	Last Time Buy
IXFH30N50Q3	IXYS	500	30	200	62	690	TO-247AD	Active
IXFR44N50Q3	IXYS	500	25	154	93	300	ISOPLUS247™	Active
IXTH30N50P	IXYS	500	30	200	70	460	TO-247	Active
IXTX46N50L	IXYS	500	46	160	260	700	PLUS247™-3	Active

Engineering Selection Recommendations

Direct Substitutes (Highest Compatibility):

IXFH36N50P and IXFH34N50P3 are the closest functional equivalents to the APT37F50B. Both devices maintain 500V Vdss rating, operate within 1A to 3A of the original 37A specification, and are packaged in TO-247AD through-hole format. Both parts are in active product status with RoHS3 compliance and MSL 1 rating. IXFH36N50P provides 36A continuous current with 540W power dissipation, while IXFH34N50P3 delivers 34A with 695W dissipation. The on-state resistance values (170mOhm) are slightly higher than the APT37F50B (150mOhm), representing a minor performance trade-off offset by improved power handling in the IXFH34N50P3.

Higher Current Alternative:

IXFH42N50P2 offers 42A continuous drain current with 145mOhm on-state resistance matching the APT37F50B specification. This part is suitable for applications requiring higher current capacity. However, IXFH42N50P2 is designated as Last Time Buy, indicating limited future availability. This part should be selected only when the additional 5A current capacity is essential to application performance.

Lower Current Alternatives:

IXFH30N50Q3 and IXTH30N50P both provide 30A continuous current at 500V Vdss. These parts are appropriate for applications where the APT37F50B's 37A rating exceeds system requirements. IXTH30N50P maintains TO-247 packaging identical to the APT37F50B, while IXFH30N50Q3 uses TO-247AD variant. Both are in active product status.

Specialized Package Options:

IXFR44N50Q3 (ISOPLUS247™ package) and IXTX46N50L (PLUS247™-3 package) represent alternative through-hole packaging formats within the 500V N-Channel MOSFET category. IXFR44N50Q3 is rated for 25A continuous current with 300W power dissipation, suitable for lower-current applications. IXTX46N50L provides 46A continuous current with 700W power dissipation and is appropriate for high-current applications. Both maintain 500V Vdss and RoHS3 compliance. Package selection depends on PCB layout constraints and thermal management requirements specific to the application.

Compliance and Availability:

All substitute parts listed are RoHS3 compliant, REACH unaffected, and carry MSL 1 (unlimited) moisture sensitivity rating, matching the APT37F50B environmental specifications. Current inventory levels range from 888 to 5580 pieces across substitute options, with IXFH34N50P3 offering the highest stock availability at 5314 pieces.

Frequently Asked Questions (FAQ)

Q: Can IXFH36N50P directly replace APT37F50B in my circuit?

A: IXFH36N50P is functionally compatible with APT37F50B for most applications. Both devices share 500V Vdss rating, similar continuous current specifications (36A vs. 37A), and TO-247 family packaging. The primary difference is on-state resistance: IXFH36N50P specifies 170mOhm compared to APT37F50B's 150mOhm. This 20mOhm increase results in slightly higher conduction losses. Verify that your thermal management design accommodates the 540W power dissipation rating of IXFH36N50P. Gate charge characteristics differ (93nC vs. 145nC), which may affect switching speed; confirm gate drive circuit compatibility.

Q: What is the difference between TO-247 and TO-247AD packaging?

A: Both TO-247 and TO-247AD are through-hole packages with identical pin configuration and mechanical footprint compatibility. TO-247AD is a variant designation used by IXYS for their HiPerFET™ series devices. PCB layouts designed for standard TO-247 packages accept TO-247AD components without modification. The functional difference lies in internal die design and electrical characteristics specific to each manufacturer's process technology, not in physical package dimensions.

Q: Why does IXFH42N50P2 show "Last Time Buy" status?

A: Last Time Buy status indicates that the manufacturer has announced end-of-life for this part number. New production will cease after a specified date, though existing inventory remains available for purchase. If IXFH42N50P2's 42A current rating is critical to your application, secure inventory during the Last Time Buy window. Alternatively, select IXTX46N50L (46A rating) or IXFH36N50P (36A rating) as long-term alternatives.

Q: Is IXFR44N50Q3 with ISOPLUS247™ packaging compatible with my TO-247 PCB layout?

A: ISOPLUS247™ is a specialized through-hole package variant with different mechanical dimensions and pin spacing compared to standard TO-247. PCB layouts designed for TO-247 packages do not directly accept ISOPLUS247™ components without redesign. Select IXFR44N50Q3 only if your PCB layout explicitly supports ISOPLUS247™ packaging or if you are redesigning the PCB footprint.

Q: How do gate charge differences affect my gate drive circuit?

A: Gate charge (Qg) determines the total charge required to switch the MOSFET from off to on state. APT37F50B specifies 145nC at 10V, while substitute parts range from 60nC to 260nC. Lower gate charge (IXFH34N50P3 at 60nC) reduces switching losses and allows faster switching with lower gate drive current. Higher gate charge (IXTX46N50L at 260nC) requires higher gate drive current and longer switching times. Verify that your gate drive circuit can supply the required charge current for your selected substitute part. Consult the gate drive circuit design specifications and the substitute part's gate charge datasheet values.

Q: Can I use IXTX46N50L (46A) instead of APT37F50B (37A) for current margin?

A: IXTX46N50L is electrically compatible with APT37F50B at 500V Vdss and provides 9A additional continuous current capacity. However, IXTX46N50L uses PLUS247™-3 packaging, which differs mechanically from APT37F50B's TO-247 [B] package. PCB layout compatibility must be verified before substitution. Additionally, IXTX46N50L specifies 260nC gate charge compared to APT37F50B's 145nC, requiring higher gate drive current. Select IXTX46N50L only if your PCB supports PLUS247™-3 footprint and your gate drive circuit can deliver the higher charge current.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed in this reference—IXFH36N50P, IXFH34N50P3, IXFH42N50P2, IXFH30N50Q3, IXFR44N50Q3, IXTH30N50P, and IXTX46N50L—are RoHS3 compliant with REACH unaffected status and MSL 1 (unlimited) moisture sensitivity rating, matching APT37F50B environmental and regulatory specifications.

Q: What is the minimum continuous current rating I can use as a substitute?

A: IXFH30N50Q3 and IXTH30N50P both provide 30A continuous current at 500V Vdss. These parts are suitable for applications where the APT37F50B's 37A rating exceeds system requirements. Verify that your application's maximum continuous current does not exceed 30A before selecting these lower-rated alternatives. Operating a MOSFET below its rated current does not degrade performance; however, operating above rated current causes thermal stress and device failure.

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