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

Diodes Incorporated MMST2222A-7

Name: MMST2222A-7
Brand: Diodes Incorporated
SKU: MMST2222A-7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMST2222A-7

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: MMST2222A-7.pdf

Description:: TRANS NPN 40V 0.6A SOT-323

Quantity:: RFQ Add To RFQ list

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Inventory:9,173

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Product details

Overview

MMST2222A-7 from Diodes Incorporated is an NPN small-signal surface-mount transistor in SOT-323 package, rated for 40 V V_CEO, 600 mA I_C, and 200 mW P_D, with h_FE = 35–300 (depending on bias), f_T = 300 MHz, and V_CE(SAT) ≤ 1.0 V at 500 mA. It serves as a general-purpose switching and amplification device in compact DC-DC feedback paths, LED drivers, and signal conditioning stages.

For engineers reviewing the MMST2222A-7 datasheet, MMST2222A-7 pinout, MMST2222A-7 application, or MMST2222A-7 equivalent, key selection considerations include its SOT-323 footprint compatibility, thermal resistance of 625 °C/W on FR-4, guaranteed h_FE across temperature (−55 to +150 °C), and low-noise performance (NF = 4.0 dB at 1 kHz).

Technical Context

This epitaxial planar NPN transistor operates in linear and saturation regions with defined DC gain curves across collector currents (100 µA to 500 mA) and temperatures (−55 to +150 °C). Its switching behavior is characterized by td = 10 ns, tr = 25 ns, ts = 225 ns, and tf = 60 ns under standardized 30 V/150 mA test conditions.

The device features low C_obo = 8 pF and C_ibo ≤ 25 pF at 1 MHz, enabling stable high-frequency operation up to 300 MHz f_T. Base-emitter and collector-emitter breakdown voltages are tightly specified (V_(BR)EBO = 6.0 V, V_(BR)CEO = 40 V), supporting reliable biasing in low-voltage logic interface circuits.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage before avalanche conduction in common-emitter configuration.
I_C (continuous)	600 mA - Continuous collector current capability at T_A = 25 °C with derating above 25 °C per Fig. 1.
P_D	200 mW - Power dissipation limit on standard FR-4 PCB; drops to ~80 mW at 100 °C ambient.
h_FE	35–300 - DC current gain range across operating points; 100 typical at I_C = 150 mA, V_CE = 10 V.
f_T	300 MHz - Frequency at which short-circuit current gain drops to unity; usable for RF preamp and oscillator bias stages.
V_CE(SAT)	≤1.0 V - Saturation voltage at I_C = 500 mA / I_B = 50 mA; ensures <100 mW loss in switch-on state.
NF	4.0 dB - Noise figure at 1 kHz, 100 µA I_C, 1 kΩ source impedance; suitable for low-noise analog front ends.

Pinout & Package

Package: SOT-323 - ultra-small surface-mount plastic case (2.20 × 1.35 × 0.90 mm), UL 94V-0 rated, moisture sensitivity Level 1, lead-free matte tin finish available.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal	Connected to ground or low-impedance return path; defines reference for V_BE and I_C control.
Base (B)	Control input	Receives bias current to modulate collector current; requires series resistor for current-limited drive.
Collector (C)	Current source terminal	Delivers switched or amplified output current; connected to load or next stage's input impedance.

Key Features

Feature	Design Value
Ultra-small SOT-323 footprint	Enables high-density PCB layouts in space-constrained applications like wearables and IoT sensor nodes.
Guaranteed h_FE over temperature	Supports stable gain in automotive cabin modules and industrial controllers operating from −55 to +150 °C.
Low V_CE(SAT) at high I_C	Reduces conduction loss in 500 mA switching loads (e.g., relay drivers), improving thermal margin on FR-4 boards.
300 MHz f_T	Permits use in local oscillator buffers and IF amplifiers in sub-GHz wireless transceivers without external compensation.
Lead-free and RoHS-compliant	Meets IPC-J-STD-020A Level 1 moisture sensitivity and global environmental compliance requirements.

Applications

LED Driver Circuit

Microcontroller GPIO Expander

Use Scenario: Driving discrete indicator LEDs or low-current RGB segments from 3.3 V or 5 V microcontroller outputs.

IC Role / Device Role: NPN switch controlling LED anode current with base driven by MCU GPIO.

Use Value: V_CE(SAT) ≤ 0.3 V at 150 mA ensures >95% efficiency and minimal self-heating in continuous blink modes.

Use Scenario: Amplifying weak analog sensor signals (e.g., thermistor, photodiode) before ADC sampling.

IC Role / Device Role: Common-emitter amplifier stage with fixed bias network and emitter degeneration.

Use Value: h_FE ≥ 100 at I_C = 1 mA enables stable 10× voltage gain with <1% nonlinearity over 0–100 °C.

DC-DC Feedback Transistor

Logic-Level Signal Translator

Use Scenario: Providing optocoupler drive current in isolated flyback converter feedback loops.

IC Role / Device Role: Switching transistor turning on/off PC817 or similar optocoupler LED.

Use Value: 600 mA I_C rating supports 20 mA opto-LED drive with 30× safety margin and fast turn-off (tf = 60 ns).

Use Scenario: Converting 1.8 V logic-high signals to 5 V-compatible levels for legacy peripherals.

IC Role / Device Role: Level-shifting emitter-follower or common-base translator.

Use Value: Low C_ibo ≤ 25 pF and f_T = 300 MHz allow clean 10 MHz square-wave translation with <1 ns jitter.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
PN2222A (TO-92)	Through-hole TO-92 package; higher R_JA = 200 °C/W; same V_CEO/I_C ratings but lower f_T (250 MHz).	Not suitable for automated SMT assembly; better for prototyping or low-volume through-hole designs.	Select when manual soldering or breadboard validation is required, not for production SMT lines.
MMBT2222A (SOT-23)	SOT-23 package (larger than SOT-323); identical electrical specs; R_JA = 350 °C/W on same PCB layout.	Acceptable where board area allows larger footprint; offers easier rework than SOT-323.	Choose when thermal margin is critical and 0.5 mm² extra board space is available.

Compared with PN2222A and MMBT2222A, MMST2222A-7 delivers the smallest footprint and highest frequency response, making it optimal for miniaturized, high-speed switching-though its 625 °C/W thermal resistance demands careful layout for >200 mW average power.

Availability

MMST2222A-7 is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO expansion, DC-DC feedback paths, and logic-level signal translation requiring stable component supply and full traceability.

Supply support for MMST2222A-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 centers across Asia and manufacturing in China, Taiwan, and the U.S.

The MMST2222A belongs to Diodes' small-signal transistor product line, engineered for high-reliability, space-constrained applications including portable electronics, automotive body control modules, and industrial sensing interfaces.

FAQ

What is the maximum junction temperature for MMST2222A-7?

The absolute maximum junction temperature is +150 °C, matching its storage temperature limit. Operation at this temperature requires strict derating of P_D per Fig. 1 in the datasheet-maximum dissipation drops to ~40 mW at 125 °C ambient on standard FR-4, assuming θ_JA = 625 °C/W.

Is MMST2222A-7 pin-compatible with the MMBT2222A?

No-MMST2222A-7 uses SOT-323 (E-B-C pin order), while MMBT2222A uses SOT-23 (E-B-C but with different pad spacing and larger dimensions). Physical placement is not interchangeable; PCB layout must be redesigned to accommodate the 2.2 × 1.35 mm SOT-323 outline and tighter 0.65 mm pin pitch.

Does MMST2222A-7 support lead-free reflow soldering?

Yes-MMST2222A-7 is qualified for lead-free reflow per J-STD-020A Level 1. Its matte tin finish withstands peak temperatures up to 260 °C, and the package meets IPC/JEDEC standards for moisture sensitivity and thermal cycling reliability.

Can MMST2222A-7 replace BC847 in existing designs?

Only with validation-BC847 has different h_FE distribution (110–800 vs. 35–300), lower V_CE(SAT) (0.2 V typ.), and SOT-23 packaging. Electrical substitution may cause gain mismatch or thermal issues; mechanical replacement requires SOT-323 footprint adaptation and thermal simulation due to higher θ_JA.

MMST2222A-7 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: SC-70, SOT-323

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 600 mA

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

Vce Saturation (Max) @ Ib, Ic:: 1V @ 50mA, 500mA

Current - Collector Cutoff (Max):: 10nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 150mA, 10V

Power - Max:: 200 mW

Frequency - Transition:: 300MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

MMST2222A-7 FAQ

1.How can I place an order for MMST2222A-7 through Aetrix?

Please submit a Request for Quotation (RFQ) for MMST2222A-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 MMST2222A-7 reliable?

The price and inventory of MMST2222A-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMST2222A-7 is usually 5 days.

3.What payment methods are accepted for MMST2222A-7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMST2222A-7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMST2222A-7?

MMST2222A-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMST2222A-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 MMST2222A-7?

For technical support, including MMST2222A-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMST2222A-7 requirements.

6.How does Aetrix verify that MMST2222A-7 is sourced from the original manufacturer or authorized distributors?

All MMST2222A-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 MMST2222A-7 meets industry standards.

7.What is the process for return or replacement of MMST2222A-7?

All MMST2222A-7 units undergo pre-shipment inspection (PSI). If there is an issue with MMST2222A-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 MMST2222A-7 part is unused and in its original packaging.

Return procedure for MMST2222A-7:

1.Submit a request within 90 days.

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

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