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

NXP Semiconductors BC638,112

Name: BC638,112
Brand: NXP Semiconductors
SKU: BC638,112
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC638,112

Manufacturer:: NXP Semiconductors

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: BC638,112.pdf

Description:: TRANS PNP 60V 1A TO-92-3

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Product details

Overview

BC638,112 from Nexperia (formerly Philips Semiconductors) is a PNP medium-power bipolar junction transistor in TO-92 (SOT54) package, rated for −60 V V_CBO, −60 V V_CEO, and −1 A continuous collector current. It delivers DC current gain (h_FE) of 63–250 at I_C = −150 mA and V_CE = −2 V, with V_CE(sat) ≤ −0.5 V at I_C = −500 mA / I_B = −50 mA, and is commonly used in audio amplifier output stages.

For engineers reviewing the BC638,112 datasheet, BC638,112 pinout, BC638,112 application, or BC638,112 equivalent, key selection considerations include its PNP polarity, TO-92 thermal resistance (R_th(j-a) = 150 K/W), complementary NPN pairing with BC637, and suitability for linear amplification and switching in low-to-medium power analog circuits.

Technical Context

The BC638,112 operates as a silicon PNP BJT optimized for medium-power linear and switching applications up to 0.83 W at T_amb ≤ 25 °C. Its junction temperature limit is 150 °C, and it exhibits low leakage (I_CBO ≤ −100 nA at 25 °C) and stable h_FE across I_C = −5 mA to −500 mA.

It features a fixed three-terminal configuration (base, collector, emitter) with defined absolute maximum ratings per IEC 60134, including peak base current (−200 mA) and emitter-base voltage (−5 V), and supports operation over ambient temperatures from −65 °C to +150 °C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CBO	−60 V - Maximum reverse voltage between collector and base with emitter open; defines safe blocking capability in common-emitter switch configurations.
V_CEO	−60 V - Maximum collector-emitter voltage with base open; sets upper limit for supply rail in amplifier or switch topologies.
I_C (DC)	−1 A - Continuous collector current rating; determines maximum steady-state load drive capability in linear or saturated operation.
h_FE	63–250 - DC current gain range at V_CE = −2 V; enables predictable base drive sizing for bias networks in Class-A/B amplifiers.
V_CE(sat)	≤ −0.5 V at I_C = −500 mA / I_B = −50 mA - Low saturation voltage ensures minimal conduction loss and heat generation in switching applications.
R_th(j-a)	150 K/W - Junction-to-ambient thermal resistance on FR4 PCB; informs heatsinking requirements and derating curves for sustained power dissipation.

Pinout & Package

BC638,112 is housed in a plastic single-ended leaded (through-hole) TO-92 package, also designated SOT54 or SC-43A, with 3 leads and standard 2.54 mm lead pitch.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Current-controlled input terminal; requires appropriate bias resistor network to set operating point in active or saturation region.
2	Collector	Main current-carrying terminal connected to higher-potential (less negative) supply rail in PNP configuration; handles full load current.
3	Emitter	Common reference terminal tied to most-negative potential (e.g., ground or −V_CC); source of majority carriers in PNP operation.

Key Features

Feature	Design Value
High DC current capability	Rated for −1 A continuous collector current, enabling robust drive for speaker loads and relay coils without external buffering.
Low saturation voltage	V_CE(sat) ≤ −0.5 V ensures <100 mW conduction loss at 500 mA, reducing thermal stress in switching regulators and driver stages.
Stable current gain over wide I_C range	h_FE remains ≥63 from 5 mA to 500 mA, supporting consistent gain in both small-signal preamp and medium-power output stages.
Complementary NPN pairing	Designed as direct complement to BC637 (NPN), facilitating matched push-pull stage design in Class-B/AB audio amplifiers.

Applications

Audio Amplifier Output Stage	DC Motor Driver (Low-Power)
Use Scenario: Final output stage in discrete Class-B or AB audio amplifiers driving 4–8 Ω speakers. IC Role / Device Role / Timing Role: PNP power transistor delivering negative half-cycle current in push-pull pair with BC637. Use Value: Delivers clean, low-distortion amplification with V_CE(sat) ≤ −0.5 V minimizing crossover distortion and thermal rise at 500 mA peak.	Use Scenario: H-bridge or single-direction driver for brushed DC motors in toys, actuators, or instrumentation. IC Role / Device Role / Timing Role: High-side PNP switch controlling motor current flow from positive rail to load. Use Value: −60 V V_CEO and −1 A I_C support 24 V systems with stall-current margin; TO-92 allows compact through-hole layout.
LED Current Regulator	Linear Voltage Regulator Pass Element
Use Scenario: Constant-current sink for high-brightness LEDs in signage or backlighting. IC Role / Device Role / Timing Role: PNP pass transistor in emitter-follower configuration, regulating LED current via base voltage control. Use Value: Tight h_FE consistency (63–250) enables precise current setting with minimal base drive variation across production lots.	Use Scenario: Series pass element in adjustable linear regulators supplying analog sensor or op-amp circuitry. IC Role / Device Role / Timing Role: PNP series regulator transistor dissipating excess voltage between unregulated input and regulated output. Use Value: R_th(j-a) = 150 K/W permits up to ~0.5 W dissipation at 50 °C ambient, supporting 100–200 mA outputs with 5–10 V drop.

Audio Amplifier Output Stage

DC Motor Driver (Low-Power)

Use Scenario: Final output stage in discrete Class-B or AB audio amplifiers driving 4–8 Ω speakers.

IC Role / Device Role / Timing Role: PNP power transistor delivering negative half-cycle current in push-pull pair with BC637.

Use Value: Delivers clean, low-distortion amplification with V_CE(sat) ≤ −0.5 V minimizing crossover distortion and thermal rise at 500 mA peak.

Use Scenario: H-bridge or single-direction driver for brushed DC motors in toys, actuators, or instrumentation.

IC Role / Device Role / Timing Role: High-side PNP switch controlling motor current flow from positive rail to load.

Use Value: −60 V V_CEO and −1 A I_C support 24 V systems with stall-current margin; TO-92 allows compact through-hole layout.

LED Current Regulator

Linear Voltage Regulator Pass Element

Use Scenario: Constant-current sink for high-brightness LEDs in signage or backlighting.

IC Role / Device Role / Timing Role: PNP pass transistor in emitter-follower configuration, regulating LED current via base voltage control.

Use Value: Tight h_FE consistency (63–250) enables precise current setting with minimal base drive variation across production lots.

Use Scenario: Series pass element in adjustable linear regulators supplying analog sensor or op-amp circuitry.

IC Role / Device Role / Timing Role: PNP series regulator transistor dissipating excess voltage between unregulated input and regulated output.

Use Value: R_th(j-a) = 150 K/W permits up to ~0.5 W dissipation at 50 °C ambient, supporting 100–200 mA outputs with 5–10 V drop.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP medium-power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC638-16	Same die, guaranteed h_FE = 100–250 (vs. BC638,112's min 63); tighter gain binning.	Preferred where predictable gain matching is required (e.g., differential pairs, feedback amplifiers).	Select BC638-16 when h_FE consistency across units is critical; BC638,112 suffices for general-purpose switching or non-matched amplification.
MPSA92	Higher V_CBO (−300 V), lower I_C (−500 mA), TO-92 package; different gain profile (h_FE = 25–100).	Better suited for high-voltage, low-current switching (e.g., CRT deflection, HV logic), not audio output stages.	Choose MPSA92 only for >100 V blocking needs; BC638,112 remains optimal for ≤60 V, ≤1 A linear/switching roles.

Compared with BC638-16 and MPSA92, BC638,112 offers balanced performance for cost-sensitive medium-power PNP applications-delivering sufficient gain and current capability without premium binning or over-spec'd voltage ratings.

Availability

BC638,112 is available at Aetrix Electronics and suitable for audio amplifiers, DC motor drivers, LED current regulators, and linear voltage regulator designs requiring stable component supply and long-term obsolescence management.

Supply support for BC638,112 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 specializing in high-volume, high-reliability discrete and logic devices, spun off from Philips Semiconductors in 2017.

The BC638,112 belongs to Nexperia's legacy medium-power bipolar transistor family, designed for robust analog signal conditioning, power switching, and audio output applications in consumer, industrial, and automotive electronics.

FAQ

What is the maximum collector-emitter voltage rating for BC638,112?

The BC638,112 has a maximum collector-emitter voltage (V_CEO) rating of −60 V under open-base conditions. This value is specified per IEC 60134 Absolute Maximum Ratings and must not be exceeded to prevent junction breakdown. Operation near this limit requires careful attention to transient spikes and thermal derating, especially above 25 °C ambient.

Is BC638,112 pin-compatible with BC637?

No, BC638,112 and BC637 are complementary transistors (PNP vs. NPN) but share identical TO-92 (SOT54) pinout: Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter. While physically interchangeable on PCBs, their opposite polarities mean they cannot substitute directly without circuit redesign-BC638,112 serves as the PNP partner to BC637 in push-pull configurations.

What is the typical DC current gain (hFE) of BC638,112 at 150 mA collector current?

At V_CE = −2 V and I_C = −150 mA, the BC638,112 exhibits a DC current gain (h_FE) ranging from 63 to 250. This wide range reflects standard manufacturing spread; for designs requiring tighter gain control, the binned variant BC638-16 (h_FE = 100–250) is recommended instead of BC638,112.

Can BC638,112 be used in switching applications?

Yes, BC638,112 is suitable for medium-speed switching applications due to its −0.5 V V_CE(sat) at I_C = −500 mA / I_B = −50 mA and transition frequency (f_T) of 100 MHz. It supports reliable saturation and turn-off in PWM-driven loads like relays and small solenoids, though switching speed is limited by minority-carrier storage time-not ideal for >100 kHz digital logic.

What is the thermal resistance from junction to ambient for BC638,112?

The BC638,112 has a thermal resistance from junction to ambient (R_th(j-a)) of 150 K/W when mounted on a standard FR4 printed-circuit board, per datasheet test conditions. This value assumes no added heatsink and governs power derating: at 75 °C ambient, maximum allowable P_tot drops to ~0.55 W to maintain T_j ≤ 150 °C.

BC638,112 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP

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

Voltage - Collector Emitter Breakdown (Max):: 60 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 50mA, 500mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 63 @ 150mA, 2V

Power - Max:: 830 mW

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC638,112 FAQ

1.How can I place an order for BC638,112 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC638,112 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 BC638,112 reliable?

The price and inventory of BC638,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC638,112 is usually 5 days.

3.What payment methods are accepted for BC638,112?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC638,112 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC638,112?

BC638,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC638,112 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 BC638,112?

For technical support, including BC638,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC638,112 requirements.

6.How does Aetrix verify that BC638,112 is sourced from the original manufacturer or authorized distributors?

All BC638,112 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 BC638,112 meets industry standards.

7.What is the process for return or replacement of BC638,112?

All BC638,112 units undergo pre-shipment inspection (PSI). If there is an issue with BC638,112, 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 BC638,112 part is unused and in its original packaging.

Return procedure for BC638,112:

1.Submit a request within 90 days.

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

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