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

Nexperia USA Inc. PMSTA42,115

Name: PMSTA42,115
Brand: Nexperia USA Inc.
SKU: PMSTA42,115
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PMSTA42,115

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: PMSTA42,115.pdf

Description:: TRANS NPN 300V 0.1A SOT-323

Quantity:: RFQ Add To RFQ list

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Product details

Overview

PMSTA42 from Nexperia is an NPN high-voltage transistor in SOT323 (SC-70) package, rated for 300 V V_CEO, 100 mA I_C, and 200 mW P_tot, with DC current gain h_FE ≥25 at 1 mA. It serves as a high-voltage switching element in telephony line interface circuits where compact size and voltage robustness are critical.

For engineers reviewing the PMSTA42 datasheet, PMSTA42 pinout, PMSTA42 application, or PMSTA42 equivalent, key selection criteria include verified V_CEO = 300 V, h_FE ≥40 at 30 mA, C_re = 3 pF, f_T = 50 MHz, and thermal resistance R_th(j-a) = 625 K/W on FR4 PCB - all confirmed per Nexperia's October 2024 product data sheet.

Technical Context

This discrete NPN bipolar junction transistor operates in linear or saturated switching mode with open-base collector-emitter breakdown of 300 V and emitter-base rating of 6 V. Its low feedback capacitance (3 pF) and 50 MHz transition frequency support stable high-voltage signal switching up to audio and low-RF frequencies.

Designed for surface-mount telephony interfaces, it delivers 500 mV V_CE(sat) at I_C = 20 mA / I_B = 2 mA and exhibits leakage currents ≤100 nA at rated blocking voltages - enabling reliable off-state isolation in ringing generator and line-feed circuits.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	300 V - maximum safe collector-emitter voltage with base open; enables use in telephone line ringing (≥90 V peak) and surge-tolerant interfaces
I_C	100 mA continuous - supports steady-state current in line feed and supervisory circuits without derating at T_amb ≤25 °C
h_FE	≥25 @ 1 mA, ≥40 @ 30 mA - ensures sufficient drive margin for base-resistor biased switching in low-power telecom modules
V_CE(sat)	≤500 mV @ I_C=20 mA, I_B=2 mA - minimizes conduction loss and self-heating during active switching
C_re	3 pF @ V_CB=20 V - limits Miller effect and improves switching stability in high-impedance collector nodes
R_th(j-a)	625 K/W - defines thermal rise on standard FR4 PCB; requires layout-aware copper area for sustained 100 mA operation

Pinout & Package

SOT323 (SC-70) plastic surface-mount package: 3-pin, 1.3 mm pitch, 2.0 × 1.25 × 0.95 mm body, tin-plated leads compatible with reflow and wave soldering per Nexperia footprint guidelines.

Pin/Terminal	Circuit Role	Design Meaning
1	Base (B)	Current-controlled input node; requires external base resistor for biasing in switching applications
2	Emitter (E)	Common reference terminal; connected to ground or negative rail in low-side switch configuration
3	Collector (C)	High-voltage output node; handles up to 300 V with controlled current path to load

Key Features

Feature	Design Value
High-voltage capability	V_CEO = 300 V enables direct integration into telephone line interface ICs without external voltage clamping
Low saturation voltage	V_CE(sat) ≤500 mV reduces power dissipation and thermal stress in pulsed 20 mA switching loads
Small-footprint packaging	SOT323 (SC-70) saves >50% board area vs. SOT23 while maintaining manufacturability on fine-pitch assembly lines
Controlled leakage performance	ICBO ≤100 nA at 200 V ensures stable off-state blocking in high-impedance telecom monitoring paths

Applications

Telephone Line Interface

Ringing Generator Circuit

Use Scenario: Isolating and switching DC feed and AC ringing signals on analog telephone lines.

IC Role / Device Role / Timing Role: NPN high-voltage switch controlling connection between line transformer and battery feed network.

Use Value: 300 V V_CEO withstands 170 Vpk ringing superimposed on -48 V DC, eliminating need for series Zener clamping.

Use Scenario: Generating 20–30 Hz, 90 V_RMS AC ringing waveform for subscriber line alerting.

IC Role / Device Role / Timing Role: High-voltage output stage switching transformer primary under microcontroller PWM control.

Use Value: Low C_re (3 pF) prevents phase shift and distortion in 25 Hz fundamental frequency output.

Line Supervision Module

Off-Hook Detection Circuit

Use Scenario: Monitoring loop current to detect on-hook/off-hook status in PBX and VoIP gateway systems.

IC Role / Device Role / Timing Role: Current-sensing switch in series with line feed resistor, activated by loop closure.

Use Value: h_FE ≥40 at 30 mA ensures reliable turn-on with minimal base drive, reducing MCU GPIO loading.

Use Scenario: Detecting subscriber lifting handset by sensing DC loop current change from ~0 mA to ~20–50 mA.

IC Role / Device Role / Timing Role: Low-leakage NPN sensor amplifying small current changes into logic-level signals.

Use Value: IEBO ≤100 nA prevents false triggering from ambient leakage in high-impedance detection nodes.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC847B,115	V_CEO = 45 V, h_FE = 200–450, P_tot = 300 mW	Not suitable for >60 V line applications; limited to low-voltage digital switching	Select only for sub-45 V logic-level or signal-switching roles where high voltage is not required
PMSTA92,115	PNP complement; V_CEO = 300 V, same package and thermal specs	Used in high-side or complementary push-pull configurations, not direct functional replacement	Choose when designing symmetrical driver stages or sourcing current from positive rails

Compared with BC847B,115, PMSTA42 provides 6.7× higher voltage rating but lower h_FE spread; versus PMSTA92,115, it enables low-side switching topology with identical footprint and thermal behavior but opposite polarity control.

Availability

PMSTA42 is available at Aetrix Electronics and suitable for telephone line interface, ringing generator, and line supervision applications requiring stable component supply, long-lifecycle availability, and consistent parametric performance across production batches.

Supply support for PMSTA42 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 high-volume, high-reliability discrete and logic devices, headquartered in Nijmegen, Netherlands, with manufacturing in Asia and Europe.

PMSTA42 belongs to Nexperia's high-voltage bipolar transistor product line, engineered specifically for analog telephony infrastructure, line card protection, and legacy PSTN interface applications demanding rugged 300 V operation in miniature packages.

FAQ

What is the maximum allowable collector-emitter voltage for PMSTA42?

The absolute maximum V_CEO is 300 V with base open, per IEC 60134 limiting values. This rating is validated under standard FR4 PCB mounting conditions and applies to continuous DC or repetitive pulse operation within thermal limits. Exceeding this voltage risks permanent junction breakdown.

Can PMSTA42 be used in place of a MOSFET for high-voltage switching?

PMSTA42 is a bipolar transistor requiring continuous base current for saturation, unlike voltage-driven MOSFETs. It is suitable for low-to-medium frequency (<100 kHz), moderate-current (<100 mA) high-voltage switching where gate drive complexity must be minimized, but not for high-efficiency or high-frequency SMPS applications.

Does PMSTA42 meet automotive qualification standards?

No. Per Nexperia's October 2024 revision history, PMSTA42 is explicitly designated as non-automotive qualified. It lacks AEC-Q101 stress testing and is intended for industrial, telecom, and consumer equipment only. Automotive alternatives require explicit "-Q" suffix parts such as PMSTA42-Q.

What is the recommended PCB footprint for reflow soldering of PMSTA42?

Nexperia specifies a reflow footprint with 0.55 mm pad width, 0.6 mm pad length, and 1.325 mm center-to-center spacing for all three pins (SOT323_FR). The total occupied area is 2.65 × 2.35 mm, with solder resist defined to expose only the copper lands - ensuring coplanarity and void-free joints under standard lead-free reflow profiles.

PMSTA42,115 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):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 300 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:: 200 mW

Frequency - Transition:: 50MHz

Operating Temperature:: 150°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

PMSTA42,115 FAQ

1.How can I place an order for PMSTA42,115 through Aetrix?

Please submit a Request for Quotation (RFQ) for PMSTA42,115 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 PMSTA42,115 reliable?

The price and inventory of PMSTA42,115 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PMSTA42,115 is usually 5 days.

3.What payment methods are accepted for PMSTA42,115?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PMSTA42,115 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PMSTA42,115?

PMSTA42,115 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PMSTA42,115 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 PMSTA42,115?

For technical support, including PMSTA42,115 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PMSTA42,115 requirements.

6.How does Aetrix verify that PMSTA42,115 is sourced from the original manufacturer or authorized distributors?

All PMSTA42,115 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 PMSTA42,115 meets industry standards.

7.What is the process for return or replacement of PMSTA42,115?

All PMSTA42,115 units undergo pre-shipment inspection (PSI). If there is an issue with PMSTA42,115, 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 PMSTA42,115 part is unused and in its original packaging.

Return procedure for PMSTA42,115:

1.Submit a request within 90 days.

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

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