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

Nexperia USA Inc. PMST3904-QX

Name: PMST3904-QX
Brand: Nexperia USA Inc.
SKU: PMST3904-QX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PMST3904-QX

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: PMST3904-QX.pdf

Description:: TRANS NPN 40V 0.2A SOT-323

Quantity:: RFQ Add To RFQ list

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Product details

Overview

PMST3904-QX from Nexperia is an AEC-Q101-qualified NPN bipolar junction transistor in SOT323 (SC-70) package, designed for automotive-grade switching and amplification. It delivers 200 mA collector current, 40 V V_CEO, DC current gain (h_FE) of 100–300 at I_C = 10 mA, and operates across −65 °C to +150 °C ambient range - used in body control modules and LED driver stages.

For engineers reviewing the PMST3904-QX datasheet, PMST3904-QX pinout, PMST3904-QX application, or PMST3904-QX equivalent, this page provides verified package mapping, validated switching timing (t_d/t_r/t_s/t_f ≤ 35/35/200/50 ns), saturation voltage specs (V_CE(sat) = 650–850 mV @ I_C=10 mA/I_B=1 mA), thermal resistance (R_th(j-a) = 625 K/W), and automotive qualification evidence per AEC-Q101.

Technical Context

This discrete NPN transistor operates as a low-voltage, medium-current switch with base-driven turn-on and controlled saturation behavior. Its h_FE variation (60–300) across I_C = 0.1–100 mA and temperature (−55 °C to +150 °C) enables predictable biasing in automotive signal conditioning circuits.

Switching performance is defined by fixed test conditions: I_Con = 1 mA, I_Coff = −1 mA, V_CC = 3 V, and V_BB = −1.9 V. Measured t_s = 200 ns dominates total delay, indicating minority-carrier storage limitation typical of standard BJT architecture - not suitable for >1 MHz hard-switching without Baker clamp.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage with base open; defines breakdown margin in 12 V automotive load switching.
I_C	200 mA - Continuous collector current rating; supports relay drivers and small-signal MOSFET gate pre-drivers.
h_FE	100–300 @ V_CE = 1 V, I_C = 10 mA - Enables stable base resistor design for predictable saturation in digital logic interfacing.
V_CE(sat)	650–850 mV @ I_C = 10 mA, I_B = 1 mA - Low saturation voltage minimizes power loss in high-duty-cycle switching applications.
t_s	200 ns - Storage time limits maximum usable switching frequency to ~500 kHz in unsaturated operation.
R_th(j-a)	625 K/W - Thermal resistance on FR4 PCB dictates derating above 25 °C ambient; full 200 mW dissipation only at T_amb ≤ 25 °C.
f_T	300 MHz - Transition frequency confirms suitability for RF pre-amplifier stages up to VHF band under low-I_C bias.

Pinout & Package

SOT323 (SC-70) plastic surface-mount package: 3-pin, 1.3 mm pitch, 2.0 mm × 1.25 mm × 0.95 mm body size, single-sided copper FR4 mounting.

Pin/Terminal	Circuit Role	Design Meaning
1	Base (B)	Current-controlled input node; requires series resistor to limit I_B ≤ 100 mA peak and ensure h_FE-based saturation.
2	Emitter (E)	Common reference terminal; tied to ground or low-side return path; carries full I_C + I_B current.
3	Collector (C)	High-side switched output; connects to load (e.g., LED anode or relay coil); must remain ≤ V_CEO during flyback events.

Key Features

Feature	Design Value
AEC-Q101 qualification	Validated for automotive use per stress-test requirements including HTGB, HTRB, and temperature cycling - enables direct placement in BCM, lighting, and sensor interface modules.
V_CEO = 40 V	Supports 24 V system transients (ISO 7637-2 Pulse 1/2a) with margin; eliminates need for external clamping in low-power loads.
Low V_CE(sat)	650–850 mV ensures <10 mW conduction loss at 10 mA drive - critical for battery-powered always-on nodes in vehicle access systems.
SC-70 footprint	0.95 mm height and 2.0 mm length enable dense layout in space-constrained ECUs and ADAS camera modules.
h_FE min = 100	Guarantees reliable turn-on with standard 5 V MCU GPIO driving 10 kΩ base resistor - simplifies firmware-safe switching logic.

Applications

Automotive Body Control Module

LED Tail Light Driver

Use Scenario: Switching 12 V incandescent or LED loads (e.g., door lock actuators, interior lamps) under microcontroller PWM control.

IC Role / Device Role / Timing Role: Discrete NPN switch providing galvanic isolation and current gain between MCU GPIO and load.

Use Value: AEC-Q101 qualification ensures reliability over 15-year vehicle lifetime; 200 mA rating covers multi-LED strings without heatsinking.

Use Scenario: Constant-current sink for red/amber LED arrays in rear combination lamps with CAN/LIN bus communication.

IC Role / Device Role / Timing Role: Linear or PWM-controlled current switch regulating LED brightness via base drive modulation.

Use Value: Low V_CE(sat) reduces thermal load in sealed lamp housings; SC-70 package fits tight optical module spacing.

Engine Bay Sensor Interface

Industrial PLC Input Conditioning

Use Scenario: Level-shifting and signal inversion for analog sensor outputs (e.g., thermistor networks, potentiometer wipers) in high-temperature engine compartments.

IC Role / Device Role / Timing Role: Amplifier stage providing gain and impedance transformation before ADC sampling.

Use Value: Stable h_FE across −55 °C to +150 °C enables accurate calibration without software compensation.

Use Scenario: Isolating 24 V DC field signals (e.g., proximity switches, limit sensors) into 3.3 V/5 V logic domains of programmable logic controllers.

IC Role / Device Role / Timing Role: Digital input buffer converting industrial voltage levels to compatible logic thresholds.

Use Value: 40 V V_CEO withstands common-mode surges on factory floor wiring; SC-70 allows high-density I/O card layouts.

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	Same SOT323 package, h_FE = 110–220, V_CEO = 45 V, but not AEC-Q101 qualified.	Lacks automotive qualification; limited to commercial/industrial environments with <85 °C max ambient.	Select when cost sensitivity outweighs automotive compliance; verify thermal derating for >85 °C operation.
MMBT3904LT1G	SOT-23 package (larger footprint), same electrical specs, AEC-Q101 qualified, R_th(j-a) = 400 K/W.	Higher power handling due to lower thermal resistance, but occupies 2.9 mm × 1.3 mm vs. 2.0 mm × 1.25 mm.	Choose when board space permits and higher continuous I_C derating is needed above 25 °C ambient.

Compared with BC847BW and MMBT3904LT1G, PMST3904-QX uniquely balances AEC-Q101 compliance, SC-70 miniaturization, and guaranteed h_FE ≥100 - making it optimal for space-constrained automotive modules where qualification and footprint are non-negotiable.

Availability

PMST3904-QX is available at Aetrix Electronics and suitable for automotive body control modules, LED lighting systems, and industrial sensor interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for PMST3904-QX 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 semiconductor expert focused on essential efficiency technologies, delivering high-performance, high-reliability discrete and logic devices for automotive, industrial, and consumer markets.

PMST3904-QX belongs to Nexperia's AEC-Q101-qualified small-signal transistor product line, engineered specifically for robust, miniaturized switching and amplification in harsh automotive environments.

FAQ

Is PMST3904-QX pin-compatible with standard MMBT3904 variants?

No - PMST3904-QX uses SOT323 (SC-70) package with pin order Base–Emitter–Collector (1–2–3), whereas MMBT3904 variants typically use SOT-23 with Emitter–Base–Collector (1–2–3). Physical layout and solder pad dimensions differ; direct replacement requires PCB redesign.

What is the maximum allowable base current for continuous operation?

The absolute maximum peak base current is 100 mA (I_BM), but continuous DC base current must be limited to ≤10 mA to avoid thermal runaway. At I_C = 100 mA and h_FE = 30 (min at high current), I_B ≈ 3.3 mA is sufficient for saturation - recommended design target.

Does PMST3904-QX support PWM switching at 25 kHz?

Yes - with t_s = 200 ns and t_f = 50 ns, total switching time is <300 ns, enabling clean 25 kHz PWM (40 µs period) with >95% duty cycle headroom. Ensure base drive strength meets I_B = I_C/10 for full saturation and minimize trace inductance.

Can PMST3904-QX replace a MOSFET in low-side switching?

Only for low-frequency, low-current (<100 mA), and low-V_DS (<5 V) cases. Unlike MOSFETs, it requires continuous base current, exhibits V_CE(sat) > 0.6 V, and has slower switching. Use only when BJT-specific gain, linearity, or cost advantages outweigh MOSFET efficiency benefits.

PMST3904-QX Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 200 mA

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

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Power - Max:: 200 mW

Frequency - Transition:: 300MHz

Operating Temperature:: -

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

PMST3904-QX FAQ

1.How can I place an order for PMST3904-QX through Aetrix?

Please submit a Request for Quotation (RFQ) for PMST3904-QX 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 PMST3904-QX reliable?

The price and inventory of PMST3904-QX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PMST3904-QX is usually 5 days.

3.What payment methods are accepted for PMST3904-QX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PMST3904-QX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PMST3904-QX?

PMST3904-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PMST3904-QX 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 PMST3904-QX?

For technical support, including PMST3904-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PMST3904-QX requirements.

6.How does Aetrix verify that PMST3904-QX is sourced from the original manufacturer or authorized distributors?

All PMST3904-QX 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 PMST3904-QX meets industry standards.

7.What is the process for return or replacement of PMST3904-QX?

All PMST3904-QX units undergo pre-shipment inspection (PSI). If there is an issue with PMST3904-QX, 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 PMST3904-QX part is unused and in its original packaging.

Return procedure for PMST3904-QX:

1.Submit a request within 90 days.

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

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