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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

Diodes Incorporated FMMT591TC

Name: FMMT591TC
Brand: Diodes Incorporated
SKU: FMMT591TC
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: FMMT591TC

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: FMMT591TC.pdf

Description:: TRANS PNP 60V 1A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Inventory:9,230

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Product details

Overview

FMMT591TC from Diodes Incorporated is a 60V PNP medium-power transistor in SOT23 package, rated for -1A continuous collector current and -2A peak pulse current, with V_CE(sat) = -295 mV at I_C = -1A/I_B = -100mA, h_FE = 155 at I_C = -1A, and used in discrete power switching and linear amplification stages of industrial DC-DC converters, LED drivers, and load control circuits.

For engineers reviewing the FMMT591TC datasheet, FMMT591TC pinout, FMMT591TC application, or FMMT591TC equivalent, key selection criteria include verified PNP polarity, SOT23 thermal derating behavior, guaranteed -60V V_CEO, low-saturation voltage under high-current drive, and automotive-grade variant availability (FMMT591Q).

Technical Context

This PNP bipolar junction transistor operates in active, saturation, and cutoff regions with defined breakdown limits: V_CBO = -80V, V_CEO = -60V, and V_EBO = -7V. Its h_FE remains stable up to -2A (min 40), supporting high-gain current amplification in switching and analog feedback paths.

Thermal performance is characterized with R_θJA = 250°C/W on 15mm × 15mm 1oz FR-4 PCB and R_θJL = 197°C/W to collector lead, enabling predictable power dissipation up to 500mW at T_A = +25°C with linear derating above 25°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-60 V - Maximum safe collector-emitter voltage before avalanche conduction in common-emitter configuration
I_C (cont.)	-1 A - Continuous DC collector current rating defining steady-state power switch capability
V_CE(sat)	-295 mV @ I_C = -1A/I_B = -100mA - Low on-state voltage drop enabling <0.3W conduction loss at full rated current
h_FE	155 @ I_C = -1A - Confirmed current gain ensuring reliable base drive sizing for switching applications
P_D	500 mW - Maximum steady-state power dissipation on standard PCB layout, limiting thermal design margin
f_T	150 MHz - Transition frequency confirming usable bandwidth for medium-speed switching (<1MHz) and RF biasing

Pinout & Package

Package: SOT23 - Surface-mount plastic package with 0.008 g mass, UL 94V-0 flammability rating, and matte tin-plated leads solderable per MIL-STD-202 Method 208.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current source terminal in PNP operation	Connected to higher potential rail; carries full load current and defines reference for base bias network
2 (Base)	Control input for minority-carrier injection	Receives negative current to turn on device; requires ≥-100mA for full saturation at I_C = -1A
3 (Collector)	Current sink terminal in PNP operation	Connected to load/ground side; thermally coupled to PCB copper for heat extraction per R_θJL = 197°C/W

Key Features

Feature	Design Value
High-voltage blocking	V_CEO = -60V enables use in 48V industrial bus and automotive battery-supplied circuits
Low saturation resistance	R_sat = 295 mΩ reduces conduction losses in high-duty-cycle switching applications
Stable gain at high current	h_FE ≥ 40 at I_C = -2A supports robust drive margin under transient overload
Automotive-compliant variant	FMMT591Q available with AEC-Q101 qualification and PPAP support for automotive systems

Applications

Industrial Power Switching

LED Constant-Current Driver

Use Scenario: Discrete high-side switch controlling 24V solenoid loads in PLC output modules.

IC Role / Device Role / Timing Role: PNP transistor operating in saturation as current-controlled switch with fixed base resistor network.

Use Value: -60V V_CEO withstands inductive kickback; -295mV V_CE(sat) limits self-heating during 100% duty cycle operation.

Use Scenario: Linear current regulator for high-brightness white LEDs in signage backlighting.

IC Role / Device Role / Timing Role: Emitter-follower configured PNP pass element with op-amp feedback loop.

Use Value: h_FE = 155 ensures precise current mirroring accuracy; 500mW P_D allows 350mA continuous LED current at ambient ≤60°C.

DC-DC Converter Bias Circuit

Load Disconnect Switch

Use Scenario: Base drive stage for synchronous rectifier MOSFETs in isolated flyback converters.

IC Role / Device Role / Timing Role: Fast-switching PNP providing negative gate drive pulses to N-channel MOSFETs.

Use Value: f_T = 150MHz supports clean 500kHz gate drive edges; -2A I_CM handles pulsed gate charge demands.

Use Scenario: Reverse-polarity protection and hot-swap enable switch in 12V embedded systems.

IC Role / Device Role / Timing Role: High-side PNP switch placed between input supply and system rail with series sense resistor.

Use Value: V_EBO = -7V permits direct microcontroller GPIO interface; -1A I_C rating matches typical board-level fuse limits.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP medium-power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ZTX653	V_CEO = -60V, I_C = -1A, but h_FE = 100 min @ I_C = -500mA only; no specified V_CE(sat) at -1A	Limited high-current gain validation; less suitable for saturated switching near I_C = -1A	Prefer FMMT591TC where guaranteed h_FE ≥ 155 at full rated current is required
MMBT591	SOT23 package same, but V_CEO = -40V and P_D = 350mW - lower voltage and power capability	Not suitable for 48V bus or >350mA continuous loads due to derated specs	Select FMMT591TC when -60V blocking or 500mW dissipation is mandatory

Compared with ZTX653 and MMBT591, FMMT591TC delivers superior high-current gain stability and higher absolute maximum ratings, making it the preferred choice for industrial 24–48V power control where thermal margin and saturation performance are critical.

Availability

FMMT591TC is available at Aetrix Electronics and suitable for industrial power switching, LED driver design, DC-DC converter bias circuits, and load disconnect applications requiring stable component supply and traceable sourcing.

Supply support for FMMT591TC includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and integrated circuits, specializing in high-reliability power management, signal integrity, and protection solutions.

FMMT591TC belongs to Diodes' FMMT series of medium-power transistors designed for industrial and automotive-grade discrete switching and amplification, emphasizing ruggedness, thermal stability, and AEC-Q101 compatibility.

FAQ

What is the maximum safe operating temperature for FMMT591TC?

The FMMT591TC has an operating junction temperature range of -55°C to +150°C. Its thermal resistance R_θJA = 250°C/W on a 15mm × 15mm 1oz FR-4 PCB means that at 25°C ambient, the junction reaches 150°C at 500mW dissipation. Derating begins linearly above 25°C, reaching zero power at 150°C ambient.

Is FMMT591TC pin-compatible with its NPN complement FMMT491?

Yes - FMMT591TC (PNP) and FMMT491 (NPN) share identical SOT23 pinout: Emitter (Pin 1), Base (Pin 2), Collector (Pin 3). This allows direct complementary placement in H-bridge, push-pull, or differential amplifier designs without layout changes.

Does FMMT591TC meet automotive qualification standards?

The standard FMMT591TC is not AEC-Q101 qualified. However, the automotive-compliant variant FMMT591Q is available separately, manufactured in IATF 16949-certified facilities and qualified to AEC-Q101 with full PPAP documentation support.

What is the recommended PCB pad layout for SOT23 mounting of FMMT591TC?

Diodes specifies SOT23 pad dimensions based on JEDEC MO-178: 0.915mm width × 1.35mm length for Pin 1 (Emitter), with 0.535mm spacing between pins. Thermal relief to 15mm × 15mm 1oz copper pour on the collector pad is required to achieve R_θJA = 250°C/W and maintain 500mW power rating.

FMMT591TC Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 1 A

Voltage - Collector Emitter Breakdown (Max):: 60 V

Vce Saturation (Max) @ Ib, Ic:: 350mV @ 100mA, 1A

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 500mA, 5V

Power - Max:: 500 mW

Frequency - Transition:: 150MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

FMMT591TC FAQ

1.How can I place an order for FMMT591TC through Aetrix?

Please submit a Request for Quotation (RFQ) for FMMT591TC on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for FMMT591TC reliable?

The price and inventory of FMMT591TC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FMMT591TC is usually 5 days.

3.What payment methods are accepted for FMMT591TC?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FMMT591TC transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for FMMT591TC?

FMMT591TC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your FMMT591TC order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for FMMT591TC?

For technical support, including FMMT591TC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FMMT591TC requirements.

6.How does Aetrix verify that FMMT591TC is sourced from the original manufacturer or authorized distributors?

All FMMT591TC products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that FMMT591TC meets industry standards.

7.What is the process for return or replacement of FMMT591TC?

All FMMT591TC units undergo pre-shipment inspection (PSI). If there is an issue with FMMT591TC, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The FMMT591TC part is unused and in its original packaging.

Return procedure for FMMT591TC:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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