Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Diodes Incorporated FMMT591ATA

Name: FMMT591ATA
Brand: Diodes Incorporated
SKU: FMMT591ATA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: FMMT591ATA

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

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

Datasheet:: FMMT591ATA.pdf

Description:: TRANS PNP 40V 1A SOT-23-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:56,923

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

FMMT591ATA from Diodes Incorporated is a 40V PNP medium-power transistor in SOT23 package, rated for -1A continuous collector current and -2A peak pulse current, with V_CE(sat) ≤ -500mV at -1A and R_sat = 350mΩ; used for power MOSFET gate driving and low-loss switching in DC-DC converters and motor control stages.

For engineers reviewing the FMMT591ATA datasheet, FMMT591ATA pinout, FMMT591ATA application, or FMMT591ATA equivalent, key selection criteria include guaranteed BV_CEO ≥ -40V, thermal resistance R_θJA = 250°C/W on standard PCB, ESD HBM rating of 4kV, and compatibility with SOT23 (Type DN) footprint and reflow profiles.

Technical Context

This PNP bipolar junction transistor operates in linear or saturated switching mode with verified h_FE = 300–800 across IC = -1mA to -1A, ft = 150MHz at V_CE = -10V/IC = -50mA, and C_obo = 10pF at V_CB = -10V - enabling fast turn-on/turn-off in high-frequency switching applications.

Its low V_BE(sat) = -1.1V at IC = -1A/IB = -100mA and tight V_CE(sat) distribution (≤ -200mV to -500mV across test conditions) support stable base drive design and predictable power loss calculation in discrete driver stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-40V - Ensures safe operation in 24V/36V rail systems with margin against transients
I_C (cont.)	-1A - Supports sustained load switching up to 1W dissipation with proper heatsinking
V_CE(sat)	≤ -500mV @ -1A/IB = -100mA - Limits conduction loss to ≤500mW at full current
R_sat	350mΩ - Enables direct comparison with logic-level MOSFETs in low-side switch emulation
h_FE	300–800 @ IC = -1mA to -1A - Allows robust base current design across operating range
f_t	150MHz - Supports switching frequencies up to ~10–20MHz with controlled edge rates
ESD HBM	4,000V - Meets IEC 61000-4-2 Level 3 for board-level handling without extra protection

Pinout & Package

Package: SOT23 (Type DN), surface-mount, 3-pin plastic case with matte tin-plated leads; moisture sensitivity level 1 per J-STD-020; weight ≈ 0.008g.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current source terminal	Connected to positive rail in high-side switch configuration; requires external base resistor for current limiting
2 (Base)	Control input	Driven low relative to emitter to saturate; IB ≤ -100mA required for full IC = -1A conduction
3 (Collector)	Current sink terminal	Connected to load; voltage swing limited to ≤ -40V; thermal path optimized to PCB copper via collector lead

Key Features

Feature	Design Value
Guaranteed BV_CEO ≥ -40V	Validated minimum breakdown ensures reliability in 24V automotive and industrial supplies
V_CE(sat) ≤ -500mV @ -1A	Reduces power loss by >30% vs. legacy PNP transistors with similar current rating
R_sat = 350mΩ	Enables accurate on-resistance modeling for thermal simulation and layout copper sizing
Complementary NPN: FMMT491A	Allows matched-pair design in push-pull or H-bridge output stages without parameter mismatch
AEC-Q101 qualified option available	Supports automotive-grade change control, PPAP, and IATF 16949 manufacturing traceability

Applications

Power MOSFET Gate Driver

Low-Side Switch Replacement

Use Scenario: Driving the gate of N-channel power MOSFETs in synchronous buck converters.

IC Role / Device Role / Timing Role: PNP switch providing fast, low-loss pull-up current during MOSFET turn-on phase.

Use Value: V_CE(sat) ≤ -500mV minimizes gate drive loss; ft = 150MHz supports <100ns switching transitions.

Use Scenario: Replacing logic-level MOSFETs in cost-sensitive 12V load switching (e.g., LED banks, solenoids).

IC Role / Device Role / Timing Role: Discrete high-current PNP switch controlled directly by MCU GPIO.

Use Value: R_sat = 350mΩ enables <1W dissipation at 1A; SOT23 footprint simplifies layout vs. TO-220 alternatives.

High-Side Load Switch

Current Mirror Reference

Use Scenario: Controlling power delivery to sensors or communication modules in always-on subsystems.

IC Role / Device Role / Timing Role: High-side switch with emitter tied to supply rail and collector feeding load.

Use Value: BV_CEO = -40V provides headroom for 24V systems; IC = -1A supports multi-sensor power domains.

Use Scenario: Precision current mirroring in analog front-ends or bias generation circuits.

IC Role / Device Role / Timing Role: Matched PNP element in Wilson or Widlar mirror topologies.

Use Value: h_FE consistency (300–800) and low V_BE(on) = -1.0V improve mirror accuracy and temperature stability.

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
ZXTN25050DFHTA	V_CEO = -50V, I_C = -1.5A, SOT23-3, h_FE = 200–400 @ -1A	Higher voltage rating but lower h_FE spread; not AEC-Q101 qualified in standard grade	Select when >40V system margin is required and base drive current budget allows lower h_FE
MMBT5401	V_CEO = -60V, I_C = -600mA, SOT23-3, V_CE(sat) = -400mV @ -500mA	Lower current capability; higher V_CE(sat) at 1A due to derating; no specified R_sat	Choose for legacy designs where 600mA max load suffices and cost is primary constraint

Compared with ZXTN25050DFHTA and MMBT5401, FMMT591ATA delivers superior saturation performance at 1A, tighter h_FE consistency across current range, and documented AEC-Q101 qualification path - making it preferred for automotive gate drivers and industrial power switches requiring predictable conduction loss.

Availability

FMMT591ATA is available at Aetrix Electronics and suitable for power MOSFET gate driving, low-loss power switching, and high-side load control requiring stable component supply and SOT23 footprint compatibility.

Supply support for FMMT591ATA 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 analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and the Americas.

FMMT591ATA belongs to Diodes' FMMT series of medium-power transistors designed specifically for high-reliability switching in automotive, industrial, and computing power management systems.

FAQ

What is the maximum allowable continuous collector current for FMMT591ATA?

The absolute maximum continuous collector current is -1A at T_A = +25°C. Derating applies above 25°C ambient: power dissipation is limited to 500mW, and R_θJA = 250°C/W means junction temperature rises ~250°C per watt. At 70°C ambient, max usable I_C drops to approximately -0.6A to maintain T_J ≤ 150°C.

Is FMMT591ATA suitable for automotive applications?

FMMT591ATA is manufactured in IATF 16949-certified facilities and supports PPAP documentation. While the standard part is not AEC-Q101 qualified, Diodes offers an automotive-grade variant (FMMT591ATX) with full AEC-Q101 stress testing, change control, and extended temperature validation - contact Diodes or Aetrix for qualification status and part numbering.

How does the SOT23 (Type DN) package differ from standard SOT23?

SOT23 (Type DN) has identical pinout (Emitter-Base-Collector on pins 1–2–3) but uses a "green" halogen- and antimony-free molding compound (UL 94V-0 rated), matte tin-plated leads, and tighter dimensional tolerances per Diodes' package outline DS33105. It is fully compatible with standard SOT23 footprints and reflow profiles.

What is the typical transition frequency (f_t) and how is it measured?

The typical f_t is 150MHz, measured under conditions V_CE = -10V, I_C = -50mA, and f = 100MHz. This indicates the frequency at which small-signal current gain drops to unity, confirming suitability for high-speed switching up to ~20MHz with adequate gain margin - critical for gate drive and RF bias applications.

FMMT591ATA 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:: Active

Transistor Type:: PNP

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

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 100mA, 1A

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 300 @ 100mA, 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

FMMT591ATA FAQ

1.How can I place an order for FMMT591ATA through Aetrix?

Please submit a Request for Quotation (RFQ) for FMMT591ATA 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 FMMT591ATA reliable?

The price and inventory of FMMT591ATA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FMMT591ATA is usually 5 days.

3.What payment methods are accepted for FMMT591ATA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FMMT591ATA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for FMMT591ATA?

FMMT591ATA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your FMMT591ATA 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 FMMT591ATA?

For technical support, including FMMT591ATA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FMMT591ATA requirements.

6.How does Aetrix verify that FMMT591ATA is sourced from the original manufacturer or authorized distributors?

All FMMT591ATA 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 FMMT591ATA meets industry standards.

7.What is the process for return or replacement of FMMT591ATA?

All FMMT591ATA units undergo pre-shipment inspection (PSI). If there is an issue with FMMT591ATA, 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 FMMT591ATA part is unused and in its original packaging.

Return procedure for FMMT591ATA:

1.Submit a request within 90 days.

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

Tech Hub

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…

2026-08-11 LDO Regulator: Dropout Voltage, Noise, PSRR and Power Dissipation

LDO regulator guide covering low dropout voltage, power dissipation, thermal design, PSRR, output noise, capacitor stability, adjustable LDO circuits, LDO vs buck converter and datasheet selection chec…

2026-08-06 Conditional Access Module: CAM, CI/CI+ and DVB Security

Conditional Access Module guide covering CAM meaning, CI/CI+ interface, smart card authorization, DVB security workflow, TV and set-top box compatibility, internal electronics, ESD protection, connecto…

2026-08-03 Electronic Component Obsolescence: EOL Risks, Replacement Options and Last-Time Buy Strategy

Guide to electronic component obsolescence covering EOL risk, PCN/PDN notices, last-time buy planning, replacement options, form-fit-function validation, counterfeit risk and BOM lifecycle management.

2026-07-29 18650 Battery: Voltage, Capacity, Charging and Pack Design

18650 battery guide covering lithium-ion cell basics, 3.6V/3.7V voltage, 4.2V charging, mAh and Wh capacity, protected cells, chargers, BMS, series-parallel packs, holders, welding and sourcing checks.…

2026-07-27 Hall Effect Sensor: Working Principle, Types, Circuits and Applications

Hall effect sensor guide covering working principle, linear and digital sensors, Arduino circuits, current sensing, speed detection, automotive applications, A3144 examples, signal filtering and datash…

2026-07-20 Product Change Notification (PCN) in Electronic Components: Meaning and Supply Chain Response

Product Change Notification guide for electronic components, covering PCN meaning, PCN vs PDN/EOL, common change types, risk levels, form-fit-function review, engineering validation, BOM control, LTB/L…

2026-07-19 Blend Door Actuator: Symptoms, Location, Reset and Replacement Guide

A practical guide to blend door actuators, covering HVAC function, symptoms, location, AC and heater issues, reset and calibration, replacement cost, electrical diagnosis, compatibility checks, and rep…