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

Nexperia USA Inc. PMMT491A,235

Name: PMMT491A,235
Brand: Nexperia USA Inc.
SKU: PMMT491A,235
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PMMT491A,235

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

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

Datasheet:: PMMT491A,235.pdf

Description:: TRANS NPN 40V 1A TO-236AB

Quantity:: RFQ Add To RFQ list

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Inventory:41,775

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Product details

Overview

PMMT491A from Nexperia is an NPN BISS (Breakthrough In Small Signal) transistor in SOT23 package, designed for high-current switching with low V_CE(sat). It delivers 1 A DC collector current, 40 V V_CEO, and 200 mV V_CE(sat) at I_C = 100 mA / I_B = 1 mA - enabling efficient power control in portable battery-powered devices.

For engineers reviewing the PMMT491A datasheet, PMMT491A pinout, PMMT491A application, or PMMT491A equivalent, key selection criteria include its 500 mW P_tot at T_amb ≤ 25 °C, h_FE of 200–900 across 1 mA–1 A I_C, thermal resistance R_th(j-a) = 500 K/W on FR4, and compatibility with SOT23 footprint constraints.

Technical Context

The PMMT491A is a silicon NPN bipolar junction transistor optimized for low-saturation, high-gain switching in space-constrained applications. Its BISS architecture provides enhanced h_FE linearity and reduced base drive requirements compared to standard small-signal transistors.

It operates with V_CEO = 40 V and V_CB0 = 40 V, supports peak collector current up to 2 A, and maintains stable gain (h_FE ≥ 200) even at I_C = 1 A - making it suitable for load switching where minimal conduction loss and predictable turn-on behavior are critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - maximum safe collector-emitter voltage under open-base condition; defines upper rail limit in switching circuits.
I_C (DC)	1 A - continuous collector current capability; enables direct driving of medium-power loads like LEDs or small relays.
V_CE(sat)	500 mV @ I_C = 1 A / I_B = 100 mA - low saturation voltage minimizes power dissipation and heat generation during on-state operation.
h_FE	200–900 - wide DC current gain range across 1 mA–1 A I_C; ensures robust base drive margin and stable switching across operating conditions.
R_th(j-a)	500 K/W - thermal resistance from junction to ambient on FR4 PCB; determines required copper area and heatsinking for 250 mW P_tot.
f_T	150 MHz - transition frequency at I_C = 50 mA / V_CE = 10 V; supports fast switching up to ~10–20 MHz practical edge rates.

Pinout & Package

SOT23 plastic surface-mounted package (TO-236AB), 3-lead, 1.3 mm × 2.9 mm footprint, 1.1 mm height; optimized for automated placement and reflow soldering on compact PCBs.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control input requiring ~100 mA peak base current to saturate at 1 A collector load; low V_BE(sat) = 1.2 V reduces driver burden.
2	Emitter	Common reference node for current return path; internally connected to substrate; must be tied to lowest potential in switching configuration.
3	Collector	Main current output terminal; rated for 40 V blocking and 1 A continuous conduction; connects to load side of switched circuit.

Key Features

Feature	Design Value
High current capability	1 A DC collector current supports direct drive of solenoids, LED strings, or logic-level MOSFET gates without external amplification.
Low V_CE(sat)	200–500 mV across 100 mA–1 A ensures <100 mW conduction loss at 1 A, reducing thermal stress in sealed enclosures.
Wide h_FE range	300–900 at low-mid currents and ≥200 at full 1 A enables consistent saturation with variable base drive or temperature drift.
BISS architecture	Optimized doping and geometry yield superior gain uniformity and lower base resistance vs. conventional small-signal transistors.

Applications

Portable Power Management

LED Driver Switching

Use Scenario: On/off control of 3.3 V or 5 V DC-DC converter enable lines or battery disconnect paths in handheld medical monitors and wireless sensors.

IC Role / Device Role / Timing Role: High-side or low-side switch providing clean, low-loss power gating with minimal quiescent current draw.

Use Value: 100 nA I_CEO ensures negligible standby leakage; 500 mW P_tot allows sustained 1 A switching without derating in 40 °C ambient.

Use Scenario: Constant-current switching for multi-segment status LEDs in industrial HMI panels and IoT gateways.

IC Role / Device Role / Timing Role: Current-sink switch controlling LED anode-to-rail or cathode-to-ground configurations with precise on/off timing.

Use Value: 150 MHz f_T supports PWM dimming up to 20 kHz without slew-induced distortion; 200 mV V_CE(sat) preserves forward voltage headroom.

Load Switching in Wearables

Signal-Level Logic Interface

Use Scenario: Power sequencing of BLE SoCs, sensors, or NFC readers in smartwatches and hearables where board space and thermal budget are constrained.

IC Role / Device Role / Timing Role: Low-footprint discrete load switch replacing integrated power switches to avoid vendor lock-in and simplify qualification.

Use Value: SOT23 package fits within 3 mm² area; R_th(j-a) = 500 K/W permits operation at 85 °C ambient with no heatsink when used at ≤700 mA.

Use Scenario: Level translation between 1.8 V microcontroller GPIO and 3.3 V peripheral enable inputs in compact embedded controllers.

IC Role / Device Role / Timing Role: Active pull-up/pull-down buffer providing current gain and voltage threshold shifting without added propagation delay.

Use Value: h_FE ≥ 300 at I_C = 1 mA ensures reliable turn-on with weak MCU outputs; V_BE = 1.1 V at I_C = 1 A confirms predictable base bias point.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN switching transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC847BW	Lower I_C (100 mA), higher V_CE(sat) (600 mV @ 100 mA), smaller h_FE range (110–800)	Not suitable for >200 mA loads; limited to signal-level switching or low-power bias networks	Select only if load current ≤100 mA and board space is tighter than thermal margin.
DMN2004K-7	MOSFET (N-channel), 20 V V_DS, 4.2 A I_D, 30 mΩ R_DS(on); gate-driven, no base current needed	Requires logic-level gate drive; unsuitable for analog gain or linear operation; better for high-efficiency, high-current switching	Prefer when efficiency >95% and I_load >500 mA are required, and gate drive voltage matches MCU IO.

Compared with BC847BW and DMN2004K-7, the PMMT491A uniquely balances 1 A current handling, sub-500 mV saturation, and bipolar simplicity - offering optimal trade-off for cost-sensitive, thermally constrained, medium-power discrete switching where gate drive complexity or current limitation is unacceptable.

Availability

PMMT491A is available at Aetrix Electronics and suitable for portable power management, LED driver switching, and load switching in wearables requiring stable component supply and long-term industrial availability.

Supply support for PMMT491A 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

Nexperia is a global leader in high-volume production of discrete semiconductors, logic ICs, and PowerMOS devices, with deep expertise in automotive-grade reliability and industrial scalability.

The PMMT491A belongs to Nexperia's BISS transistor product line - engineered specifically for high-current, low-saturation switching in space- and power-constrained consumer and industrial electronics.

FAQ

What is the maximum continuous collector current for PMMT491A?

The PMMT491A supports 1 A DC collector current (I_C) at T_amb ≤ 25 °C with derating above that ambient. At 85 °C ambient, maximum I_C drops to approximately 650 mA due to thermal limits imposed by its 500 K/W R_th(j-a) and 250 mW P_tot rating on FR4 PCB.

Is PMMT491A pin-compatible with standard SOT23 NPN transistors?

Yes - PMMT491A uses standard SOT23 pinout (1=Base, 2=Emitter, 3=Collector), matching industry conventions including BC846–BC848, MMBT4401, and DXT491A. No layout change is needed when substituting into existing SOT23 footprints designed for NPN transistors.

Does PMMT491A require a base resistor in typical switching applications?

Yes - a series base resistor is mandatory to limit I_B and ensure saturation. For 1 A I_C with h_FE ≥ 200, minimum I_B = 5 mA is required; using 3.3 V drive, a 470 Ω resistor delivers ~6.2 mA I_B, guaranteeing hard saturation while staying within 1 A I_BM peak rating.

What is the PNP complement part number for PMMT491A?

The official PNP complement is PMMT591A, sharing identical SOT23 package, voltage ratings (−40 V V_ECO, −40 V V_EB0), and current capability (1 A I_E). Both parts are characterized for matched performance in push-pull or complementary switching topologies.

PMMT491A,235 Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 1 A

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

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 100mA, 1A

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 300 @ 500mA, 5V

Power - Max:: 250 mW

Frequency - Transition:: 150MHz

Operating Temperature:: 150°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q100

Mounting Type:: Surface Mount

Supplier Device Package:: TO-236AB

PMMT491A,235 FAQ

1.How can I place an order for PMMT491A,235 through Aetrix?

Please submit a Request for Quotation (RFQ) for PMMT491A,235 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 PMMT491A,235 reliable?

The price and inventory of PMMT491A,235 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PMMT491A,235 is usually 5 days.

3.What payment methods are accepted for PMMT491A,235?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PMMT491A,235 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PMMT491A,235?

PMMT491A,235 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PMMT491A,235 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 PMMT491A,235?

For technical support, including PMMT491A,235 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PMMT491A,235 requirements.

6.How does Aetrix verify that PMMT491A,235 is sourced from the original manufacturer or authorized distributors?

All PMMT491A,235 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 PMMT491A,235 meets industry standards.

7.What is the process for return or replacement of PMMT491A,235?

All PMMT491A,235 units undergo pre-shipment inspection (PSI). If there is an issue with PMMT491A,235, 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 PMMT491A,235 part is unused and in its original packaging.

Return procedure for PMMT491A,235:

1.Submit a request within 90 days.

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

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