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 MMST4403-7

Name: MMST4403-7
Brand: Diodes Incorporated
SKU: MMST4403-7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: MMST4403-7

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: -

Datasheet:: MMST4403-7.pdf

Description:: TRANS PNP 40V 0.6A SC70-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:1,623

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

Product details

Overview

MMST4403-7 from Diodes Incorporated is a 40V PNP small-signal transistor in SOT323 package, rated for -600mA continuous collector current, -40V V_CEO, and 200mW power dissipation. It delivers low saturation voltage (−0.75V max at −500mA), high DC current gain (h_FE = 30–300), and 200MHz f_T, supporting switching and amplification in compact DC-DC bias networks and level-shifting circuits.

For engineers reviewing the MMST4403-7 datasheet, MMST4403-7 pinout, MMST4403-7 application, or MMST4403-7 equivalent, key selection criteria include verified PNP polarity, SOT323 thermal resistance (R_θJA = 625°C/W), V_CE(sat) performance under −150mA/−500mA drive, h_FE variation across IC = −100µA to −500mA, and JEDEC-compliant reliability for non-automotive industrial use.

Technical Context

This PNP bipolar junction transistor operates in active, saturation, and cutoff regions with defined breakdown limits: V_CBO = −40V, V_EBO = −5V, and guaranteed ICEX ≤ −100nA at V_CE = −35V. Its small-signal parameters include h_ie = 1.5–15kΩ, h_fe = 60–500, and Cob = 8.5pF at −10V, enabling stable gain and bandwidth control in low-power analog stages.

Switching behavior is characterized by td = 15ns, tr = 20ns, ts = 225ns, and tf = 30ns under −30V V_CE and −15mA base drive-indicating suitability for medium-speed digital logic interfacing and PWM-driven load control where storage time must be managed.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−40V: Maximum reverse-biased collector-emitter voltage before avalanche breakdown; defines safe operating range in high-side switch configurations.
I_C (cont.)	−600mA: Continuous collector current rating; supports robust current sourcing in driver stages without derating below 25°C ambient.
P_D	200mW: Power dissipation limit on FR-4 PCB; requires thermal design consideration above ~85°C ambient per Fig.1 derating curve.
V_CE(sat)	−0.40V to −0.75V: Confirmed saturation voltage at −150mA/−15mA and −500mA/−50mA drive; enables <0.375W conduction loss in 5V logic-level switches.
f_T	200MHz: Current-gain bandwidth product at −10V V_CE, −20mA I_C; validates usable RF amplification up to UHF band in low-noise preamp designs.
h_FE	30–300: DC current gain spanning µA to mA collector currents; ensures predictable base drive sizing across wide dynamic range of bias conditions.
R_θJA	625°C/W: Junction-to-ambient thermal resistance on standard FR-4; implies ~125°C junction rise at full 200mW dissipation in still air.

Pinout & Package

Package: SOT323 - ultra-small surface-mount plastic package (2.15mm × 2.10mm × 0.95mm), moisture sensitivity level 1, lead-free matte tin plating, UL 94V-0 rated molding compound, 0.006g weight.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current source terminal for PNP operation	Connected to higher potential rail; carries full load current; requires low-impedance return path to minimize V_EB drop.
2 (Base)	Control input for minority-carrier injection	Receives negative bias relative to emitter to turn on; IB = −50mA required for full saturation at −500mA I_C.
3 (Collector)	Current sink terminal	Typically tied to load and ground reference; reverse voltage rating (−40V) defines maximum off-state blocking capability.

Key Features

Feature	Design Value
Low V_CE(sat)	−0.40V at −150mA ensures <60mW conduction loss in 5V logic interfaces, reducing self-heating and improving efficiency in battery-powered systems.
High h_FE consistency	h_FE ≥ 30 at −100µA and ≥ 20 at −500mA enables single-transistor bias networks without external gain stabilization components.
SOT323 footprint	0.65mm pitch, 2.15mm × 2.10mm body enables high-density placement in space-constrained IoT sensor nodes and wearable power management modules.
JEDEC-qualified reliability	Qualified to AEC-Q standards for high-reliability industrial use-no automotive qualification, but validated for extended temperature operation (−55°C to +150°C).

Applications

LED Driver Stage

Level-Shifting Interface

Use Scenario: Driving 20mA indicator LEDs from 3.3V microcontroller GPIO pins with inverted logic.

IC Role / Device Role / Timing Role: PNP switch sinking current from V_CC through LED to GPIO; provides logic inversion and current gain.

Use Value: V_CE(sat) ≤ −0.4V at −20mA ensures >2.8V forward drop across LED, maintaining brightness while limiting MCU pin stress.

Use Scenario: Translating 1.8V logic outputs to 5V-tolerant inputs in mixed-voltage MCU peripherals.

IC Role / Device Role / Timing Role: Active-low level shifter using emitter-follower configuration with pull-up to 5V rail.

Use Value: h_FE ≥ 100 at −1mA enables <10µA base drive, minimizing loading on low-drive-strength 1.8V sources.

DC-DC Feedback Bias

Relay Driver Circuit

Use Scenario: Providing precise bias current to optocoupler LED in isolated flyback converter feedback loop.

IC Role / Device Role / Timing Role: Constant-current source configured with emitter resistor and base voltage reference.

Use Value: V_BE(sat) = −0.75V to −0.95V ensures stable 1mA–5mA LED current over temperature with <±5% drift.

Use Scenario: Switching 12V/100mA relay coil controlled by 3.3V microcontroller output.

IC Role / Device Role / Timing Role: High-side PNP switch with base resistor network; handles inductive kickback via snubber or clamp diode.

Use Value: V_CEO = −40V exceeds relay flyback voltage; ts = 225ns allows clean turn-off before back-EMF peak.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP small-signal transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT4403 (SOT23)	Same electrical specs but larger SOT23 package (R_θJA = 350°C/W); 200mW rating applies only with heatsink pad.	Better thermal performance in high-duty-cycle switching; incompatible pinout (E-B-C vs. E-B-C top-view differs).	Select when board layout allows SOT23 and thermal margin is critical; verify PCB pad compatibility.
DXT4403 (SOT363)	Matched dual PNP array; individual device specs identical but shared thermal mass increases R_θJA to 750°C/W.	Used where two synchronized PNP switches needed (e.g., H-bridge half-bridge); not suitable for single-device replacement.	Choose only for dual-channel requirements; avoid for single-transistor upgrades due to thermal penalty and cost premium.

Compared with MMBT4403 and DXT4403, MMST4403-7 offers optimal density for space-limited designs without sacrificing V_CEO or f_T, though its 625°C/W thermal resistance demands careful ambient temperature management above 70°C.

Availability

MMST4403-7 is available at Aetrix Electronics and suitable for LED driver stages, level-shifting interfaces, DC-DC feedback bias networks, and relay driver circuits requiring stable component supply and JEDEC-qualified reliability.

Supply support for MMST4403-7 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 North America.

The MMST4403 belongs to Diodes' general-purpose bipolar transistor product line, engineered for cost-sensitive, high-volume industrial and consumer applications where small size, consistent h_FE, and low saturation voltage are prioritized over automotive qualification.

FAQ

Is MMST4403-7 qualified for automotive applications?

No. MMST4403-7 is not AEC-Q101 qualified. Diodes offers automotive-grade variants with Q-suffix (e.g., MMST4403Q-7-F) manufactured in IATF 16949-certified facilities and PPAP-capable. This part meets JEDEC high-reliability standards but lacks automotive change control and stress testing.

What is the correct pinout orientation for SOT323 package marking 'K3T'?

Top view, left-to-right: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. The 'K3T' marking is adjacent to Pin 1. This matches Diodes' official SOT323 outline drawing and is confirmed in DS30083 Rev. 9-2 page 2 (Pinout – Top View section).

Can MMST4403-7 replace MMST4401 in a circuit?

No-it cannot serve as a direct replacement because MMST4401 is an NPN transistor with opposite polarity. Swapping them would invert circuit functionality. They are complementary types intended for matched pair designs (e.g., push-pull amplifiers), not drop-in substitutes.

What is the maximum safe operating temperature for continuous 200mW dissipation?

At 200mW, junction temperature rise is ΔT = P × R_θJA = 0.2W × 625°C/W = 125°C. With T_J(max) = +150°C, maximum ambient temperature is 150°C − 125°C = +25°C. Derating is required above 25°C ambient per Fig.1; at +70°C ambient, max power drops to ~120mW.

MMST4403-7 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: *

Package/Case:: -

Packaging:: Cut Tape (CT)

Product Status:: Active

Transistor Type:: -

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

Voltage - Collector Emitter Breakdown (Max):: -

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Power - Max:: -

Frequency - Transition:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

MMST4403-7 FAQ

1.How can I place an order for MMST4403-7 through Aetrix?

Please submit a Request for Quotation (RFQ) for MMST4403-7 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 MMST4403-7 reliable?

The price and inventory of MMST4403-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMST4403-7 is usually 5 days.

3.What payment methods are accepted for MMST4403-7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMST4403-7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMST4403-7?

MMST4403-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMST4403-7 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 MMST4403-7?

For technical support, including MMST4403-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMST4403-7 requirements.

6.How does Aetrix verify that MMST4403-7 is sourced from the original manufacturer or authorized distributors?

All MMST4403-7 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 MMST4403-7 meets industry standards.

7.What is the process for return or replacement of MMST4403-7?

All MMST4403-7 units undergo pre-shipment inspection (PSI). If there is an issue with MMST4403-7, 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 MMST4403-7 part is unused and in its original packaging.

Return procedure for MMST4403-7:

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…