FDC636P Equivalent & Substitute Parts

Part Overview

The FDC636P is a P-Channel MOSFET manufactured by onsemi, rated for 20V drain-to-source voltage with 2.8A continuous drain current at 25°C. The device is packaged in SuperSOT-6 (SOT-23-6 Thin, TSOT-23-6) surface mount configuration and is designed for low-power switching applications requiring P-channel enhancement-mode operation.

The FDC636P is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications currently utilizing this component.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	20	V
Continuous Drain Current (Id) @ 25°C	2.8	A
On-State Resistance (Rds On Max) @ Id, Vgs	130 mOhm @ 2.8A, 4.5V	mOhm
Gate-Source Voltage (Vgs Max)	±8	V
Power Dissipation (Max)	1.6	W
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount
Package Type	SOT-23-6 Thin, TSOT-23-6
FET Type	P-Channel
Technology	MOSFET (Metal Oxide)

Substitute Part Grouping Explanation

Substitution eligibility for the FDC636P is determined by the following critical parameters:

Mandatory Matching Criteria:

FET Type: P-Channel
Technology: MOSFET (Metal Oxide)
Drain-to-Source Voltage (Vdss): 20V minimum
Mounting Type: Surface Mount
Operating Temperature Range: -55°C to 150°C (TJ)

Functional Compatibility Criteria:

Continuous Drain Current (Id) @ 25°C: Equal to or greater than 2.8A
On-State Resistance (Rds On): Equal to or lower than 130 mOhm at rated conditions
Power Dissipation: Equal to or greater than 1.6W
Gate-Source Voltage (Vgs Max): Equal to or greater than ±8V

Package Compatibility: Substitute parts must be housed in SOT-23-6 Thin or TSOT-23-6 surface mount packages to ensure mechanical and electrical compatibility with existing PCB layouts.

The identified substitute parts meet these criteria with variations in specific parameters that do not compromise functional performance in applications designed for the FDC636P.

Parameter Comparison

Parameter	FDC636P	NTGS3443T1G	AO6415
Manufacturer	onsemi	onsemi	Alpha & Omega Semiconductor Inc.
Product Status	Obsolete	Active	Not For New Designs
FET Type	P-Channel	P-Channel	P-Channel
Technology	MOSFET (Metal Oxide)	MOSFET (Metal Oxide)	MOSFET (Metal Oxide)
Vdss (V)	20	20	20
Id @ 25°C (A)	2.8	2.2	3.3
Rds On (Max) (mOhm)	130 @ 2.8A, 4.5V	65 @ 4.4A, 4.5V	75 @ 3.3A, 10V
Vgs(th) (Max) @ 250µA (V)	1	1.5	1.4
Gate Charge (Qg) @ 4.5V (nC)	8.5	15	6
Vgs (Max) (V)	±8	±12	±12
Input Capacitance (Ciss) (pF)	390 @ 10V	565 @ 5V	620 @ 10V
Power Dissipation (Max) (W)	1.6	0.5	1.25
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Package / Case	SOT-23-6 Thin, TSOT-23-6	SOT-23-6 Thin, TSOT-23-6	SC-74, SOT-457
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected
ECCN	EAR99	EAR99	EAR99

Engineering Selection Recommendations

NTGS3443T1G (onsemi)

The NTGS3443T1G is an active product from onsemi with full production support and availability. This part meets all mandatory substitution criteria with equivalent Vdss (20V) and operating temperature range (-55°C to 150°C). The continuous drain current rating of 2.2A is lower than the FDC636P specification of 2.8A; however, the on-state resistance of 65 mOhm is significantly lower, resulting in reduced power dissipation during operation. The NTGS3443T1G is suitable for applications where the 2.2A current rating is sufficient and where lower on-state resistance provides thermal or efficiency benefits. The higher Vgs(Max) rating of ±12V provides additional gate drive margin compared to the FDC636P.

AO6415 (Alpha & Omega Semiconductor Inc.)

The AO6415 is classified as "Not For New Designs" and is therefore not recommended for new product development. However, this part is available in high inventory quantities and meets all mandatory substitution criteria. The AO6415 provides superior continuous drain current capability at 3.3A, exceeding the FDC636P specification of 2.8A. The on-state resistance of 75 mOhm is lower than the FDC636P, and power dissipation capability of 1.25W is lower than the FDC636P specification of 1.6W. The package type (SC-74, SOT-457) differs from the FDC636P (SOT-23-6 Thin, TSOT-23-6), requiring PCB layout modification. The AO6415 is suitable only for legacy system maintenance where existing designs can accommodate package differences.

For new designs and ongoing production requiring direct replacement capability, the NTGS3443T1G is the recommended substitute due to its active product status and full compliance with all mandatory electrical and environmental specifications.

Frequently Asked Questions (FAQ)

Q: Can the NTGS3443T1G be used as a direct replacement for the FDC636P in existing designs?

A: The NTGS3443T1G meets all mandatory electrical and environmental specifications for substitution. Both parts are housed in SOT-23-6 Thin / TSOT-23-6 packages and are pin-compatible. The primary design consideration is the lower continuous drain current rating of 2.2A versus 2.8A for the FDC636P. Applications operating below 2.2A continuous drain current can use the NTGS3443T1G without modification. Applications requiring the full 2.8A rating require current derating analysis.

Q: What is the significance of the lower power dissipation rating in the NTGS3443T1G?

A: The NTGS3443T1G has a maximum power dissipation rating of 500 mW compared to 1.6W for the FDC636P. This reflects the lower continuous drain current specification. The lower on-state resistance (65 mOhm versus 130 mOhm) results in reduced I²R losses during operation. Thermal performance depends on application duty cycle, switching frequency, and PCB thermal design. Applications with intermittent switching or lower average current benefit from the improved on-state resistance characteristics.

Q: Why does the AO6415 have a different package designation?

A: The AO6415 is packaged in SC-74 or SOT-457, which differs from the FDC636P SOT-23-6 Thin / TSOT-23-6 package. Although both are six-pin surface mount packages, the physical dimensions and pin layouts differ. PCB layout modification is required to accommodate the AO6415. The AO6415 is suitable only for legacy system maintenance where design changes are acceptable.

Q: What is the impact of higher gate charge in the NTGS3443T1G?

A: The NTGS3443T1G has a gate charge specification of 15 nC at 4.5V compared to 8.5 nC for the FDC636P. Higher gate charge requires longer switching times and increased gate drive current from the control circuit. Applications with high-frequency switching or current-limited gate drive circuits require analysis to confirm adequate gate drive capability. The higher Vgs(Max) rating of ±12V provides additional margin for gate drive voltage selection.

Q: Are all three parts compliant with environmental and regulatory requirements?

A: All three parts (FDC636P, NTGS3443T1G, and AO6415) have identical REACH Status (REACH Unaffected), ECCN classification (EAR99), and Moisture Sensitivity Level (MSL 1 - Unlimited). The NTGS3443T1G and AO6415 are RoHS3 Compliant. All parts meet the specified operating temperature range of -55°C to 150°C (TJ). Environmental and regulatory compliance is equivalent across all three parts.

Q: What inventory considerations apply to these substitute parts?

A: The FDC636P has 1,190 pieces in stock as an obsolete product with no ongoing production. The NTGS3443T1G has 38,400 pieces in stock as an active product with full production support. The AO6415 has 81,390 pieces in stock but is classified as "Not For New Designs," indicating limited future availability and no manufacturer support for new applications. For long-term supply chain planning, the NTGS3443T1G is the preferred substitute.

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