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

onsemi MMBT5550LT1

Name: MMBT5550LT1
Brand: onsemi
SKU: MMBT5550LT1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMBT5550LT1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: -

Datasheet:: MMBT5550LT1.pdf

Description:: TRANS SS NPN 140V HV SOT23

Quantity:: RFQ Add To RFQ list

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Inventory:6,123

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Product details

Overview

MMBT5550LT1 from onsemi is an NPN silicon high-voltage transistor in SOT-23 package, rated for 140 V_CEO, 600 mA continuous collector current, and 225 mW power dissipation on FR-5 board. It serves as a general-purpose switching or amplification device in high-voltage interface circuits, such as CRT deflection drivers and industrial relay controls.

For engineers reviewing the MMBT5550LT1 datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO = 140 V, h_FE ≥ 60 at I_C = 1 mA, V_CE(sat) ≤ 0.25 V at I_C/I_B = 10, AEC-Q101 qualification, and Pb-free SOT-23 packaging.

Technical Context

This discrete NPN bipolar junction transistor operates with a maximum collector-emitter breakdown voltage of 140 Vdc and supports DC current gain (h_FE) from 60 to 250 across I_C = 1–50 mA at V_CE = 5 V. Its base-emitter saturation voltage reaches 1.0 V at I_C = 10 mA/I_B = 1 mA.

Thermal performance is defined by R_JA = 556 °C/W on FR-5 board and 417 °C/W on alumina substrate. Junction temperature range spans −55 °C to +150 °C, with ESD robustness >8 kV (HBM) and >400 V (MM).

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	140 Vdc - supports high-side switching in 100–120 V AC-derived supply rails
I_C Continuous	600 mAdc - sufficient for driving small relays, LED strings, or gate resistors in MOSFET-based stages
h_FE @ I_C=1 mA	60–250 - enables stable low-current amplification in signal conditioning front-ends
V_CE(sat) @ I_C/I_B=10	≤0.25 V - minimizes conduction loss in saturated-switch applications
P_D @ T_A=25°C	225 mW on FR-5 board - defines thermal derating limit for PCB-level power handling
f_T	100 MHz @ V_CE=1 V - suitable for audio-frequency amplification and medium-speed switching

Pinout & Package

SOT-23 (TO-236) package, 2.90 × 1.30 × 1.00 mm, case 318, style 6. Marking includes device code and date code; Pb-free compliant.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control input node requiring ~1 mA drive for full saturation at 10 mA collector load
2	Emitter	Common reference terminal; tied to ground or low-side return path in switch configurations
3	Collector	High-voltage output node; handles up to 140 V transient during inductive load turn-off

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive under-hood and body-control module use with PPAP capability
Pb-free, Halogen-free/BFR-free	Complies with RoHS Directive 2011/65/EU and JEDEC JS709C material requirements
V_CBO = 160 V	Enables safe operation with 120 V AC line transients without clamping circuitry
ESD HBM > 8 kV	Reduces risk of assembly-line damage during automated PCB handling and reflow

Applications

Industrial Relay Drivers	High-Voltage Signal Switching
Use Scenario: Driving 24–48 VDC coil relays in programmable logic controllers and motor starters. IC Role / Device Role / Timing Role: NPN switch controlling relay coil current with fast turn-on/turn-off via base resistor network. Use Value: V_CEO = 140 V withstands back-EMF spikes up to 120 V, eliminating need for external flyback diodes in many designs.	Use Scenario: Selecting between dual high-voltage analog signals in test equipment multiplexers. IC Role / Device Role / Timing Role: Discrete NPN switch enabling or blocking signal paths in 100 V-range analog front-ends. Use Value: Low V_CE(sat) ≤ 0.25 V preserves signal integrity and minimizes insertion loss at 10 mA load currents.
CRT Deflection Circuits	LED String Current Control
Use Scenario: Horizontal deflection yoke drive in legacy monochrome display systems. IC Role / Device Role / Timing Role: High-voltage, medium-speed switching transistor handling repetitive 15.7 kHz sawtooth waveforms. Use Value: f_T = 100 MHz ensures adequate bandwidth for sharp edge fidelity in deflection timing.	Use Scenario: Constant-current sink for 3–5 white LED series strings powered from 100–120 V DC bus. IC Role / Device Role / Timing Role: Linear-mode current regulator using emitter degeneration resistor and base bias network. Use Value: h_FE stability over −55 °C to +150 °C maintains consistent LED brightness across operating temperature range.

Industrial Relay Drivers

High-Voltage Signal Switching

Use Scenario: Driving 24–48 VDC coil relays in programmable logic controllers and motor starters.

IC Role / Device Role / Timing Role: NPN switch controlling relay coil current with fast turn-on/turn-off via base resistor network.

Use Value: V_CEO = 140 V withstands back-EMF spikes up to 120 V, eliminating need for external flyback diodes in many designs.

Use Scenario: Selecting between dual high-voltage analog signals in test equipment multiplexers.

IC Role / Device Role / Timing Role: Discrete NPN switch enabling or blocking signal paths in 100 V-range analog front-ends.

Use Value: Low V_CE(sat) ≤ 0.25 V preserves signal integrity and minimizes insertion loss at 10 mA load currents.

CRT Deflection Circuits

LED String Current Control

Use Scenario: Horizontal deflection yoke drive in legacy monochrome display systems.

IC Role / Device Role / Timing Role: High-voltage, medium-speed switching transistor handling repetitive 15.7 kHz sawtooth waveforms.

Use Value: f_T = 100 MHz ensures adequate bandwidth for sharp edge fidelity in deflection timing.

Use Scenario: Constant-current sink for 3–5 white LED series strings powered from 100–120 V DC bus.

IC Role / Device Role / Timing Role: Linear-mode current regulator using emitter degeneration resistor and base bias network.

Use Value: h_FE stability over −55 °C to +150 °C maintains consistent LED brightness across operating temperature range.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN high-voltage transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT5551LT1G	V_CEO = 160 V, V_CBO = 180 V, h_FE min = 80 @ I_C = 1 mA	Higher voltage rating suits 150 V rail applications; otherwise identical SOT-23 footprint and biasing	Select when system transients exceed 140 V or higher DC gain is required at low I_C
ZTX653	V_CEO = 150 V, P_D = 1 W (SOT-89), h_FE = 100–800 @ I_C = 10 mA	Larger package enables higher power dissipation but requires PCB layout change	Choose for >225 mW continuous dissipation needs where thermal margin is critical

Compared with MMBT5550LT1, MMBT5551LT1G offers higher voltage headroom with no layout impact, while ZTX653 provides significantly higher power handling at the cost of larger footprint and different thermal path design.

Availability

MMBT5550LT1 is available at Aetrix Electronics and suitable for industrial relay drivers, high-voltage signal switching, and CRT deflection circuits requiring stable component supply and automotive-grade reliability.

Supply support for MMBT5550LT1 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

onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MMBT5550LT1 belongs to onsemi's high-voltage bipolar transistor product line, engineered for robust switching and linear operation in space-constrained, high-reliability systems operating up to 140 V.

FAQ

What is the maximum collector-emitter voltage rating for MMBT5550LT1?

The MMBT5550LT1 has a maximum collector-emitter voltage (V_CEO) rating of 140 Vdc, verified per onsemi's datasheet revision 14 (May 2023). This rating applies under specified test conditions: I_C = 1.0 mAdc and I_B = 0. Exceeding this voltage risks irreversible breakdown and permanent device failure. Designers must ensure all operating transients remain within this limit, especially in inductive load switching.

Is MMBT5550LT1 AEC-Q101 qualified and PPAP capable?

Yes, the MMBT5550LT1 is explicitly AEC-Q101 qualified and PPAP capable, as confirmed in the "Features" section of the official onsemi datasheet. The NSV prefix variant (NSVMMBT5550LT1G) further indicates compliance with automotive-specific site and control change requirements. This qualification covers temperature cycling, humidity testing, and mechanical stress validation per AEC standards.

What is the DC current gain (h_FE) range for MMBT5550LT1 at I_C = 10 mA?

The MMBT5550LT1 exhibits a DC current gain (h_FE) range of 60 to 250 at I_C = 10 mA and V_CE = 5.0 Vdc, per the Electrical Characteristics table in the onsemi datasheet. This wide spread reflects process variation and must be accounted for in bias network design-especially in linear amplifier or precision current-source applications where gain tolerance affects accuracy.

Does MMBT5550LT1 have built-in ESD protection, and what level is specified?

Yes, the MMBT5550LT1 features built-in ESD protection rated at >8000 V per Human Body Model (HBM) and >400 V per Machine Model (MM), as stated in the Maximum Ratings table. These values are measured per JESD22-A114 and JESD22-A115 standards. While this improves robustness during handling and assembly, external protection remains recommended in high-noise environments or direct user-accessible interfaces.

What is the thermal resistance (R_JA) of MMBT5550LT1 on FR-5 board?

The thermal resistance from junction-to-ambient (R_JA) for MMBT5550LT1 is 556 °C/W when mounted on an FR-5 board (1.0 × 0.75 × 0.062 in.), per Note 1 in the Thermal Characteristics table. This value assumes natural convection and defines the worst-case thermal gradient under standard PCB layout conditions. Derating is required at 1.8 mW/°C above 25 °C ambient.

MMBT5550LT1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: *

Package/Case:: -

Packaging:: Cut Tape (CT)

Product Status:: Obsolete

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:: -

MMBT5550LT1 FAQ

1.How can I place an order for MMBT5550LT1 through Aetrix?

Please submit a Request for Quotation (RFQ) for MMBT5550LT1 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 MMBT5550LT1 reliable?

The price and inventory of MMBT5550LT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBT5550LT1 is usually 5 days.

3.What payment methods are accepted for MMBT5550LT1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBT5550LT1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMBT5550LT1?

MMBT5550LT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMBT5550LT1 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 MMBT5550LT1?

For technical support, including MMBT5550LT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBT5550LT1 requirements.

6.How does Aetrix verify that MMBT5550LT1 is sourced from the original manufacturer or authorized distributors?

All MMBT5550LT1 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 MMBT5550LT1 meets industry standards.

7.What is the process for return or replacement of MMBT5550LT1?

All MMBT5550LT1 units undergo pre-shipment inspection (PSI). If there is an issue with MMBT5550LT1, 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 MMBT5550LT1 part is unused and in its original packaging.

Return procedure for MMBT5550LT1:

1.Submit a request within 90 days.

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

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