FMMT591AQTC Equivalent & Substitute Parts

Part Overview

The FMMT591AQTC is a surface mount PNP bipolar junction transistor manufactured by Diodes Incorporated. This device is classified as a mid-performance transistor in the automotive-grade AEC-Q101 series, designed for general-purpose switching and amplification applications. The part is currently active in production with 1031 pieces available in new original inventory. Substitute parts are necessary to address supply chain continuity, inventory availability, or specific packaging and compliance requirements across different manufacturing batches and distribution channels.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Maximum Collector Current (Ic)	1	A
Collector-Emitter Breakdown Voltage (Max)	40	V
Vce Saturation (Max)	500	mV @ 100mA, 1A
Collector Cutoff Current (Max)	100	nA
DC Current Gain (hFE Min)	300	@ 100mA, 5V
Maximum Power Dissipation	500	mW
Transition Frequency	150	MHz
Operating Temperature Range	-55 to 150	°C (TJ)
Package Type	SOT-23-3 (TO-236-3, SC-59)	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

All substitute parts listed are parametric equivalents of the FMMT591AQTC. Substitution is based on identical electrical and mechanical specifications across the following critical parameters:

Transistor polarity and type (PNP)
Maximum collector current rating (1 A)
Collector-emitter breakdown voltage (40 V)
Saturation voltage characteristics (500 mV @ 100mA, 1A)
DC current gain minimum specification (300 @ 100mA, 5V)
Maximum power dissipation (500 mW)
Transition frequency (150 MHz)
Operating temperature range (-55°C to 150°C)
Package configuration (SOT-23-3)
Surface mount mounting type
RoHS3 compliance status

The substitute parts differ only in packaging designation codes (TA, QTA, TC suffixes) and inventory availability. These designations reflect different manufacturing batches, tape and reel configurations, or distribution channels from Diodes Incorporated, but do not alter the electrical or mechanical performance characteristics.

Parameter Comparison

Parameter	FMMT591AQTC	FMMT591AQTA	FMMT591ATA	FMMT591ATC
Manufacturer	Diodes Incorporated	Diodes Incorporated	Diodes Incorporated	Diodes Incorporated
Category	Transistors, Bipolar (BJT)	Transistors, Bipolar (BJT)	Transistors, Bipolar (BJT)	Transistors, Bipolar (BJT)
Transistor Type	PNP	PNP	PNP	PNP
Ic (Max)	1 A	1 A	1 A	1 A
Vce Breakdown (Max)	40 V	40 V	40 V	40 V
Vce Saturation (Max)	500 mV @ 100mA, 1A	500 mV @ 100mA, 1A	500 mV @ 100mA, 1A	500 mV @ 100mA, 1A
Ic Cutoff (Max)	100 nA	100 nA	100 nA	100 nA
hFE (Min)	300 @ 100mA, 5V	300 @ 100mA, 5V	300 @ 100mA, 5V	300 @ 100mA, 5V
Power (Max)	500 mW	500 mW	500 mW	500 mW
Frequency - Transition	150 MHz	150 MHz	150 MHz	150 MHz
Operating Temperature	-55°C to 150°C (TJ)	-55°C to 150°C (TJ)	-55°C to 150°C (TJ)	-55°C to 150°C (TJ)
Package / Case	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Packaging	Tape & Reel (TR)	Tape & Reel (TR)	Tape & Reel (TR)	Tape & Reel (TR)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected
ECCN	EAR99	EAR99	EAR99	EAR99
HTSUS	8541.21.0075	8541.21.0075	8541.21.0075	8541.21.0075
Product Status	Active	Active	Active	Active

Engineering Selection Recommendations

All listed substitute parts are direct parametric equivalents to the FMMT591AQTC and are suitable for one-to-one replacement in circuit designs. Selection among these parts should be based on the following factors:

Inventory Availability: FMMT591ATA offers the highest inventory level at 72,500 pieces, followed by FMMT591ATC at 35,300 pieces and FMMT591AQTA at 23,300 pieces. The main part FMMT591AQTC has 1,031 pieces available.

Compliance and Certifications: All parts maintain identical RoHS3 compliance, REACH unaffected status, and EAR99 export classification. All parts are active products from Diodes Incorporated with no end-of-life notices.

Moisture Sensitivity: The substitute parts FMMT591AQTA, FMMT591ATA, and FMMT591ATC specify Moisture Sensitivity Level (MSL) 1 (Unlimited), indicating no moisture sensitivity restrictions during storage and handling.

Series Classification: The main part FMMT591AQTC is designated as part of the Automotive, AEC-Q101 series. The substitute parts do not carry explicit series designation in the provided data but maintain identical electrical specifications and surface mount SOT-23-3 packaging.

Parts may be selected interchangeably based on supply chain requirements, manufacturing batch preferences, or specific packaging reel configurations without affecting circuit performance or reliability.

Frequently Asked Questions (FAQ)

Q: Can FMMT591AQTA, FMMT591ATA, and FMMT591ATC be used interchangeably with FMMT591AQTC?

A: Yes. All four parts are parametric equivalents with identical electrical specifications, maximum ratings, and performance characteristics. They share the same SOT-23-3 package configuration and surface mount mounting type. Substitution is direct and does not require circuit redesign or re-qualification.

Q: What do the different suffix designations (AQTC, AQTA, ATA, ATC) indicate?

A: The suffix designations reflect different manufacturing batches, tape and reel configurations, or distribution channels from Diodes Incorporated. These designations do not alter electrical performance, mechanical compatibility, or compliance status. All parts are manufactured to identical specifications.

Q: Are there any differences in operating temperature range among these parts?

A: No. All parts operate across the identical temperature range of -55°C to 150°C (junction temperature). There are no thermal performance differences.

Q: Do all substitute parts meet the same compliance requirements?

A: Yes. All parts are RoHS3 compliant, REACH unaffected, and classified under ECCN EAR99. All parts carry the same HTSUS code (8541.21.0075). Compliance status is identical across all listed parts.

Q: What is the significance of the Moisture Sensitivity Level (MSL) 1 specification on the substitute parts?

A: MSL 1 (Unlimited) indicates that these parts have no moisture sensitivity restrictions. They can be stored and handled without special moisture control measures, providing flexibility in inventory management and supply chain logistics.

Q: Can the FMMT591AQTC be used in automotive applications?

A: The FMMT591AQTC is designated as part of the Automotive, AEC-Q101 series, indicating it meets automotive-grade reliability and performance standards. The substitute parts maintain identical electrical specifications but do not carry explicit automotive series designation in the provided documentation.

Q: Are there any package or pinout differences between these parts?

A: No. All parts use the SOT-23-3 package (also designated TO-236-3 or SC-59). Pinout, lead spacing, and mechanical dimensions are identical. Direct PCB footprint compatibility is assured.

Q: Which substitute part should be selected for new designs?

A: Selection should be based on current inventory availability and supply chain requirements. FMMT591ATA offers the highest inventory level and represents the most readily available option. All parts are equally suitable for new designs from an electrical and mechanical standpoint.

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