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

onsemi MMBTA43LT1

Name: MMBTA43LT1
Brand: onsemi
SKU: MMBTA43LT1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMBTA43LT1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: MMBTA43LT1.pdf

Description:: TRANS NPN 200V 0.05A SOT23-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,272

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Product details

Overview

MMBTA43LT1 from onsemi is an NPN silicon high-voltage general-purpose transistor in SOT-23 package, rated for 200 V_CEO, 500 mA continuous collector current, and 225 mW power dissipation on FR-5 board. It delivers h_FE ≥ 40 at I_C = 10 mA, V_CE = 10 V, with V_CE(sat) ≤ 0.5 V at I_C = 20 mA / I_B = 2 mA, used in high-side switching and voltage amplifier stages of industrial control interfaces.

For engineers reviewing the MMBTA43LT1 datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CEO = 200 V rating, SOT-23 thermal performance (R_JA = 556 °C/W on FR-5), h_FE consistency across temperature, and Pb-free RoHS-compliant marking (M1E M).

Technical Context

The MMBTA43LT1 operates as a medium-power NPN bipolar junction transistor optimized for high-voltage linear and switching applications. Its 200 V_CEO and 200 V_CBO ratings support operation in flyback snubbers and relay drivers, while f_T = 50 MHz enables use in low-frequency RF amplification up to 10 MHz.

It features V_BE(sat) ≤ 0.9 V at I_C = 20 mA / I_B = 2 mA and C_cb = 4.0 pF at V_CB = 20 V, supporting fast turn-off in pulse-width modulated loads and stable biasing in discrete gain stages without external compensation.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	200 Vdc - supports switching of 170 V RMS AC lines with safety margin
I_C (continuous)	500 mAdc - drives small relays, LED arrays, or logic-level interface loads
h_FE	≥40 at I_C = 10 mA - ensures reliable saturation with standard 10 kΩ base resistors
V_CE(sat)	≤0.5 V at I_C/I_B = 10 - minimizes conduction loss in 5–12 V DC switching rails
C_cb	4.0 pF at V_CB = 20 V - limits Miller effect in <10 MHz amplifier designs
R_JA (FR-5)	556 °C/W - defines thermal derating to 1.8 mW/°C above 25°C ambient

Pinout & Package

SOT-23 (TO-236) plastic surface-mount package, 2.90 × 1.30 × 1.00 mm body, 1.90 mm lead pitch, JEDEC registered CASE 318 STYLE 6.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Current-controlled input node; requires series resistor to limit I_B per h_FE target
2	Emitter	Common reference terminal; tied to ground or low-side return path in switch configurations
3	Collector	High-voltage output node; connects to load supply rail up to 200 V

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive under-hood temperature cycling (−55°C to +150°C)
Pb-free, Halogen-free, RoHS compliant	Meets EU Directive 2011/65/EU and JESD204B material restrictions
V_EBO = 6.0 V	Enables direct connection to 5 V logic without base protection diodes
ICBO ≤ 0.1 µA at V_CB = 160 V	Ensures low leakage in high-impedance bias networks over full temperature range

Applications

Industrial Relay Drivers	High-Voltage Logic Level Shifting
Use Scenario: Driving 24 VDC or 120 VAC coil relays in PLC I/O modules with microcontroller GPIO. IC Role / Device Role / Timing Role: High-voltage NPN switch sinking coil current through emitter-to-ground path. Use Value: 200 V_CEO withstands relay back-EMF spikes; V_CE(sat) ≤ 0.5 V reduces heat rise in compact PCB layouts.	Use Scenario: Translating 3.3 V or 5 V MCU outputs to control 24–48 V industrial sensors or actuators. IC Role / Device Role / Timing Role: Active-low level shifter with grounded emitter and collector pulled to higher rail. Use Value: h_FE ≥ 40 ensures full saturation with standard 10 kΩ pull-up; C_cb = 4.0 pF avoids signal distortion at 100 kHz switching.
DC-DC Converter Snubber Circuits	Discrete Audio Preamp Stages
Use Scenario: Clamping voltage spikes across MOSFET drains in flyback or forward converters. IC Role / Device Role / Timing Role: Fast-switching clamp transistor conducting transient energy into RC network. Use Value: f_T = 50 MHz supports sub-100 ns turn-on; 200 V_CBO handles reflected primary transients without breakdown.	Use Scenario: Low-noise common-emitter gain stage in analog sensor signal conditioning before ADC. IC Role / Device Role / Timing Role: Linear-mode amplifier biased at I_C = 1–10 mA for optimal h_FE and noise figure. Use Value: V_BE(sat) ≤ 0.9 V enables precise bias point setting; low C_cb maintains bandwidth >1 MHz at moderate gains.

Industrial Relay Drivers

High-Voltage Logic Level Shifting

Use Scenario: Driving 24 VDC or 120 VAC coil relays in PLC I/O modules with microcontroller GPIO.

IC Role / Device Role / Timing Role: High-voltage NPN switch sinking coil current through emitter-to-ground path.

Use Value: 200 V_CEO withstands relay back-EMF spikes; V_CE(sat) ≤ 0.5 V reduces heat rise in compact PCB layouts.

Use Scenario: Translating 3.3 V or 5 V MCU outputs to control 24–48 V industrial sensors or actuators.

IC Role / Device Role / Timing Role: Active-low level shifter with grounded emitter and collector pulled to higher rail.

Use Value: h_FE ≥ 40 ensures full saturation with standard 10 kΩ pull-up; C_cb = 4.0 pF avoids signal distortion at 100 kHz switching.

DC-DC Converter Snubber Circuits

Discrete Audio Preamp Stages

Use Scenario: Clamping voltage spikes across MOSFET drains in flyback or forward converters.

IC Role / Device Role / Timing Role: Fast-switching clamp transistor conducting transient energy into RC network.

Use Value: f_T = 50 MHz supports sub-100 ns turn-on; 200 V_CBO handles reflected primary transients without breakdown.

Use Scenario: Low-noise common-emitter gain stage in analog sensor signal conditioning before ADC.

IC Role / Device Role / Timing Role: Linear-mode amplifier biased at I_C = 1–10 mA for optimal h_FE and noise figure.

Use Value: V_BE(sat) ≤ 0.9 V enables precise bias point setting; low C_cb maintains bandwidth >1 MHz at moderate gains.

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
ZTX653	V_CEO = 250 V, h_FE = 100–300 (min 100), SOT-23 but higher gain spread	Higher gain variability requires tighter base resistor tolerance; better for precision current mirrors	Select ZTX653 when h_FE > 100 is required and V_CEO margin > 50 V is critical
BC846B	V_CEO = 65 V, h_FE = 200–450, same SOT-23 footprint but lower voltage rating	Not suitable for >100 V applications; preferred for low-voltage digital switching only	Choose BC846B only in 5–24 V systems where gain consistency outweighs voltage headroom

Compared with ZTX653 and BC846B, the MMBTA43LT1 provides balanced trade-offs: sufficient 200 V rating for industrial mains-referenced circuits, predictable h_FE ≥ 40, and proven AEC-Q101 qualification-making it optimal for cost-sensitive, thermally constrained relay and snubber designs where voltage margin and reliability are prioritized over ultra-high gain.

Availability

MMBTA43LT1 is available at Aetrix Electronics and suitable for industrial relay drivers, high-voltage level shifters, and DC-DC converter snubber circuits requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for MMBTA43LT1 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 (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MMBTA43LT1 belongs to onsemi's high-voltage general-purpose transistor family, designed specifically for robust, cost-effective switching and amplification in space-constrained industrial controls and automotive subsystems.

FAQ

What is the maximum collector-emitter voltage rating for the MMBTA43LT1?

The MMBTA43LT1 has a guaranteed minimum V_CEO rating of 200 Vdc under test conditions (I_C = 1.0 mAdc, I_B = 0). This rating is validated per JEDEC JESD22-A108 stress testing and applies across the full operating temperature range of −55°C to +150°C. The MMBTA43LT1 must not be operated beyond this limit to ensure long-term reliability.

Is the MMBTA43LT1 suitable for automotive applications?

Yes, the MMBTA43LT1 is AEC-Q101 qualified and PPAP capable, with full temperature cycling, humidity, and mechanical stress validation for automotive under-hood environments. Its marking code "M1E M" confirms automotive-grade traceability, and its −55°C to +150°C junction temperature range meets ISO/TS 16949 requirements for engine control and body electronics.

What is the thermal resistance of the MMBTA43LT1 on a standard FR-5 PCB?

The MMBTA43LT1 exhibits R_JA = 556 °C/W when mounted on a 1.0 × 0.75 × 0.062 inch FR-5 board at T_A = 25°C. Power dissipation must be derated by 1.8 mW/°C above 25°C ambient, limiting usable PD to 135 mW at 100°C ambient. Thermal vias and copper pour significantly improve real-world performance.

Does the MMBTA43LT1 have a specified current-gain bandwidth product?

Yes, the MMBTA43LT1 has a typical f_T of 50 MHz measured at I_C = 10 mAdc, V_CE = 20 Vdc, and f = 100 MHz. This value is confirmed in the "Small-Signal Characteristics" table of the official onsemi datasheet and supports stable operation in low-frequency RF amplifiers and fast-switching snubber circuits up to 10 MHz.

What are the exact pin assignments for the MMBTA43LT1 in SOT-23 package?

The MMBTA43LT1 uses SOT-23 CASE 318 STYLE 6 pinout: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector. This configuration is explicitly shown in the "Mechanical Case Outline" section of the onsemi datasheet and verified across all production lots marked "M1E M". No alternate pinouts apply to this device variant.

MMBTA43LT1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 50 mA

Voltage - Collector Emitter Breakdown (Max):: 200 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 2mA, 20mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 30mA, 10V

Power - Max:: 225 mW

Frequency - Transition:: 50MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

MMBTA43LT1 FAQ

1.How can I place an order for MMBTA43LT1 through Aetrix?

Please submit a Request for Quotation (RFQ) for MMBTA43LT1 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 MMBTA43LT1 reliable?

The price and inventory of MMBTA43LT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBTA43LT1 is usually 5 days.

3.What payment methods are accepted for MMBTA43LT1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBTA43LT1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMBTA43LT1?

MMBTA43LT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMBTA43LT1 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 MMBTA43LT1?

For technical support, including MMBTA43LT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBTA43LT1 requirements.

6.How does Aetrix verify that MMBTA43LT1 is sourced from the original manufacturer or authorized distributors?

All MMBTA43LT1 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 MMBTA43LT1 meets industry standards.

7.What is the process for return or replacement of MMBTA43LT1?

All MMBTA43LT1 units undergo pre-shipment inspection (PSI). If there is an issue with MMBTA43LT1, 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 MMBTA43LT1 part is unused and in its original packaging.

Return procedure for MMBTA43LT1:

1.Submit a request within 90 days.

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

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