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onsemi MMBT4126LT1
- Part No.:
- MMBT4126LT1
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- -
- Datasheet:
-
MMBT4126LT1.pdf
- Description:
- TRANS SS GP PNP 25V SOT23
- Quantity:
- Payment:
- Shipping:
Inventory:9,673
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Product details
Overview
MMBT4126LT1 from onsemi is a PNP silicon general-purpose transistor in SOT-23 package, rated for −25 V VCEO, −200 mA IC, and 225 mW power dissipation on FR-5 board. It delivers DC current gain (hFE) of 120–300 at −2 mA IC, −1 V VCE, and supports audio amplification and low-speed switching in battery-powered sensor interfaces.
For engineers reviewing the MMBT4126LT1 datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP polarity, SOT-23 pinout (Base-Emitter-Collector), −25 V breakdown rating, <−0.4 V VCE(sat) at −50 mA/−5 mA drive, and RoHS-compliant Pb-free packaging.
Technical Context
This discrete PNP bipolar junction transistor operates in active, saturation, and cutoff regions with defined VBE(sat) ≤ −0.95 V and VCE(sat) ≤ −0.4 V under −50 mA collector current and −5 mA base drive. Its fT of 250 MHz enables stable small-signal amplification up to mid-VHF range.
Thermal performance is characterized by RJA = 556 °C/W on FR-5 board and 417 °C/W on alumina substrate, with junction temperature range spanning −55°C to +150°C. Input capacitance Cibo ≤ 10 pF and output capacitance Cobo ≤ 4.5 pF support predictable high-frequency behavior in bias networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | −25 V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration. |
| IC | −200 mA - Continuous collector current limit defining maximum load-handling capability. |
| hFE | 120–300 - DC current gain range at −2 mA IC, enabling predictable base drive sizing for switching. |
| VCE(sat) | ≤ −0.4 V - Low saturation voltage ensures minimal power loss and heat generation in switch-mode operation. |
| fT | 250 MHz - Transition frequency confirming usable bandwidth for audio and low-RF signal amplification. |
| RJA | 556 °C/W - Junction-to-ambient thermal resistance on standard FR-5 PCB, guiding heatsinking requirements. |
Pinout & Package
SOT-23 (TO-236) surface-mount package, 2.90 × 1.30 × 1.00 mm body size, 1.90 mm lead pitch, case 318, style 6 marking. Moisture sensitivity level 1, Pb-free, RoHS compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Base | Control terminal; forward-biased with negative voltage relative to emitter to enable conduction. |
| 2 | Emitter | Current source terminal; connected to higher potential in PNP configuration (e.g., VCC rail). |
| 3 | Collector | Output terminal; sinks current to load when transistor is active or saturated. |
Key Features
| Feature | Design Value |
|---|---|
| ESD robustness | HBM > 4000 V and MM > 400 V - Reduces risk of handling damage during assembly and test. |
| Pb-free & RoHS compliance | Fully halogen-free/BFR-free construction - Meets global environmental regulations without derating. |
| Low VCE(sat) | ≤ −0.4 V at −50 mA/−5 mA - Enables efficient switching in low-voltage battery systems (e.g., 3.3 V logic control). |
| High hFE consistency | Min 120 at −2 mA IC - Supports reliable biasing with minimal base current in linear amplifier stages. |
Applications
| Audio Pre-amplifier Stage | Level-Shifting Interface |
|---|---|
Use Scenario: Amplifying weak microphone signals in portable voice recorders before ADC sampling. IC Role / Device Role / Timing Role: PNP common-emitter small-signal amplifier with fixed bias network. Use Value: 250 MHz fT and 4 dB noise figure at 1 kHz ensure clean gain up to 20 kHz without distortion or excessive noise floor rise. |
Use Scenario: Translating 5 V logic outputs to 3.3 V compatible inputs in mixed-voltage microcontroller systems. IC Role / Device Role / Timing Role: Active-low level shifter using emitter-follower or common-base configuration. Use Value: −25 V VCEO and −4 V VEBO provide margin against transient overshoot; low Cibo (≤10 pF) preserves edge integrity at ≤1 MHz toggle rates. |
| LED Current Sink Driver | Power Rail Enable Switch |
Use Scenario: Driving indicator LEDs from MCU GPIO pins in industrial HMI panels. IC Role / Device Role / Timing Role: Saturated PNP switch controlling LED anode connection to VCC. Use Value: −200 mA IC rating and ≤−0.4 V VCE(sat) allow driving multiple LEDs in parallel with <0.1 W dissipation per device. |
Use Scenario: Enabling/disabling 3.3 V or 5 V subsystem rails via microcontroller-controlled ON/OFF command. IC Role / Device Role / Timing Role: High-side PNP pass switch with base resistor network. Use Value: −25 V VCBO and −55°C to +150°C TJ range support reliable operation in automotive and industrial power management modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP general-purpose transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC807-25LT1G | Higher hFE (min 250 vs. 120), same SOT-23 package and −45 V VCEO; slightly higher VCE(sat) (−0.7 V @ −500 mA). | Better suited for high-gain linear amplification; less optimal for low-saturation switching at <−50 mA. | Select BC807-25LT1G when gain stability across temperature is critical; retain MMBT4126LT1 for cost-sensitive, moderate-current switching. |
| PN2907A | TO-92 through-hole package, −60 V VCEO, −600 mA IC, but larger footprint and lower fT (≈100 MHz). | Used where manual assembly or legacy board compatibility is required; not suitable for space-constrained SMT designs. | Choose PN2907A only for through-hole prototyping or repair; MMBT4126LT1 remains preferred for automated SMT production. |
Compared with BC807-25LT1G and PN2907A, the MMBT4126LT1 offers balanced hFE, low VCE(sat), and compact SOT-23 packaging-making it optimal for volume-manufactured consumer and industrial PCBs requiring reliable, low-cost PNP switching below 200 mA.
Availability
MMBT4126LT1 is available at Aetrix Electronics and suitable for audio pre-amplifiers, level-shifting interfaces, LED current sink drivers, and power rail enable switches requiring stable component supply and consistent parametric performance across production lots.
Supply support for MMBT4126LT1 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 management, analog, sensors, and discrete devices for automotive, industrial, and consumer markets.
The MMBT4126LT1 belongs to onsemi's general-purpose bipolar transistor product line, engineered for cost-effective, high-reliability switching and amplification in space-constrained, low-power electronic systems.
FAQ
What is the pin configuration of the MMBT4126LT1?
The MMBT4126LT1 uses SOT-23 package with Style 6 pinout: Pin 1 is Base, Pin 2 is Emitter, and Pin 3 is Collector. This configuration is confirmed in the official onsemi datasheet (Publication Order Number MMBT4126LT1/D, Rev. 4, October 2024) and matches mechanical outline CASE 318.
Is the MMBT4126LT1 RoHS compliant and Pb-free?
Yes, the MMBT4126LT1 is RoHS compliant and Pb-free, as explicitly stated in the "Features" section of the onsemi datasheet. The "G" suffix in MMBT4126LT1G denotes the Pb-free version, and the part marking includes a "G" or microdot to indicate compliance.
What is the maximum operating temperature for the MMBT4126LT1?
The MMBT4126LT1 has a junction and storage temperature range of −55°C to +150°C, per the Thermal Characteristics table in the official datasheet. This allows deployment in extended-temperature industrial and automotive under-hood environments when mounted on appropriate PCB substrates.
Does the MMBT4126LT1 support high-frequency signal amplification?
Yes, the MMBT4126LT1 has an fT of 250 MHz, measured at −10 mA IC, −20 V VCE, and 100 MHz. This makes it suitable for small-signal amplification in audio and low-RF applications up to ~50 MHz, though gain rolls off above fT/10.
How does the MMBT4126LT1 compare to NPN alternatives like the MMBT3904LT1?
The MMBT4126LT1 is a PNP transistor optimized for high-side switching and complementary pair use, whereas the MMBT3904LT1 is NPN for low-side configurations. They share SOT-23 packaging and similar voltage/current ratings but differ in polarity, biasing direction, and typical circuit topology-requiring separate design validation for each role.
MMBT4126LT1 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:
- -
MMBT4126LT1 FAQ
1.How can I place an order for MMBT4126LT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBT4126LT1 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 MMBT4126LT1 reliable?
The price and inventory of MMBT4126LT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBT4126LT1 is usually 5 days.
3.What payment methods are accepted for MMBT4126LT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBT4126LT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBT4126LT1?
MMBT4126LT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBT4126LT1 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 MMBT4126LT1?
For technical support, including MMBT4126LT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBT4126LT1 requirements.
6.How does Aetrix verify that MMBT4126LT1 is sourced from the original manufacturer or authorized distributors?
All MMBT4126LT1 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 MMBT4126LT1 meets industry standards.
7.What is the process for return or replacement of MMBT4126LT1?
All MMBT4126LT1 units undergo pre-shipment inspection (PSI). If there is an issue with MMBT4126LT1, 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 MMBT4126LT1 part is unused and in its original packaging.
Return procedure for MMBT4126LT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMBT4126LT1 Tags
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