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

Nexperia USA Inc. BC51PASX

Name: BC51PASX
Brand: Nexperia USA Inc.
SKU: BC51PASX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC51PASX

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: 3-UDFN Exposed Pad

Datasheet:: BC51PASX.pdf

Description:: TRANS PNP 45V 1A DFN2020D-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,310

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Product details

Overview

BC51PASX from Nexperia is a PNP medium power transistor in ultra-thin DFN2020D-3 (SOT1061D) package, rated for −45 V V_CEO, −1 A continuous collector current, and 1.65 W total power dissipation at T_amb = 25 °C. It delivers h_FE = 63–250 at V_CE = −2 V, I_C = −150 mA, and is AEC-Q101 qualified for automotive-grade reliability in high-side switch and MOSFET driver circuits.

For engineers reviewing the BC51PASX datasheet, BC51PASX pinout, BC51PASX application, or BC51PASX equivalent, this device is selected for compact, thermally enhanced PNP switching in space-constrained linear regulators, battery-powered systems, and power management stages where side-wettable flanks enable AOI-compatible solder joint inspection.

Technical Context

This PNP bipolar junction transistor operates with emitter-grounded configuration and supports DC switching and linear amplification up to f_T = 145 MHz. Its thermal design leverages an exposed collector pad for low R_th(j-sp) = 20 K/W and R_th(j-a) as low as 76 K/W on 4-layer FR4 PCBs with 1 cm² collector pad.

It features pulsed peak current capability of −2 A (t_p ≤ 1 ms), V_BE = −1 V at I_C = −500 mA, and V_CE(sat) = −500 mV at I_C = −500 mA / I_B = −50 mA - enabling efficient saturation in high-current switching nodes.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V: Maximum safe collector-emitter voltage with base open; defines high-side switch voltage headroom in 36 V automotive systems.
I_C (continuous)	−1 A: Continuous DC collector current rating; supports load switching up to ~12 W at 12 V supply with adequate heatsinking.
h_FE	63–250: DC current gain range at V_CE = −2 V, I_C = −150 mA; enables predictable base drive sizing for stable switching thresholds.
P_tot	1.65 W (T_amb = 25 °C, 4-layer FR4 + 1 cm² collector pad): Total power dissipation limit; sets thermal derating boundary for sustained operation.
f_T	145 MHz: Transition frequency at V_CE = −5 V, I_C = −50 mA; confirms suitability for high-speed switching above 10 MHz in gate driving applications.
R_th(j-a)	76 K/W: Junction-to-ambient thermal resistance under optimized PCB layout; allows ~21.7 °C/W per watt temperature rise above ambient.
AEC-Q101	Qualified: Meets stress test requirements for discrete semiconductors in automotive applications; supports under-hood and body-control module use.

Pinout & Package

BC51PASX uses the DFN2020D-3 (SOT1061D) leadless plastic package: 2 mm × 2 mm × 0.65 mm body, 1.3 mm pitch, side-wettable flanks for AOI, and exposed collector pad for thermal and electrical conduction.

Pin/Terminal	Circuit Role	Design Meaning
1	Base (B)	Current-controlled input node; requires −50 mA base drive for full saturation at −500 mA collector load.
2	Emitter (E)	Reference terminal tied to system ground or higher potential; carries full load current in high-side configuration.
3	Collector (C)	Main output terminal connected to load; electrically and thermally coupled to exposed copper pad on PCB bottom side.

Key Features

Feature	Design Value
Exposed collector pad	Enables direct thermal coupling to PCB copper; reduces R_th(j-a) by up to 58% vs. standard SOT23 when using 1 cm² mounting area.
Side-wettable flanks (SWF)	Allows automated optical inspection (AOI) of solder fillets without X-ray; improves manufacturing yield in high-volume SMT lines.
Two h_FE variants	BC51PAS (63–250) and BC51-10PAS (63–160) offer gain binning for consistent base resistor selection across production lots.
Ultra-thin profile	0.65 mm max height enables stacking in ultra-low-profile modules such as portable medical sensors and wearables.
−55 °C to +150 °C operation	Rated ambient and junction temperature range supports engine bay, industrial control, and outdoor power equipment deployment.

Applications

Linear Voltage Regulators

Battery-Driven Devices

Use Scenario: Pass transistor in adjustable LDO designs delivering 3.3 V/1 A from 12 V battery input.

IC Role / Device Role / Timing Role: PNP pass element controlling output voltage via base bias network; operates in linear region with <1 V dropout.

Use Value: Low V_CE(sat) (−500 mV) minimizes power loss and thermal load; AEC-Q101 qualification ensures regulator stability in automotive start-stop systems.

Use Scenario: Load switch enabling/disabling 5 V rail to Bluetooth audio module in wireless earbuds.

IC Role / Device Role / Timing Role: High-side PNP switch controlled by MCU GPIO; provides fast turn-on (<1 µs) and reverse-polarity protection.

Use Value: Compact DFN2020D-3 footprint saves >60% board area vs. SOT23; side-wettable flanks ensure reliable reflow in miniaturized HDI PCBs.

MOSFET Drivers

Power Management

Use Scenario: Level-shifting stage driving N-channel high-side MOSFET gate in buck converter synchronous rectifier.

IC Role / Device Role / Timing Role: Fast-switching PNP pull-down element complementing NMOS gate driver; handles −1 A peak sink current.

Use Value: f_T = 145 MHz supports clean 10–20 MHz gate transitions; low C_c = 15 pF prevents Miller-induced oscillation.

Use Scenario: Current-sense amplifier front-end transistor in smart battery fuel gauge IC for Li-ion packs.

IC Role / Device Role / Timing Role: Precision current mirror reference transistor with matched h_FE binning (BC51-16PAS: 100–250).

Use Value: Tight h_FE spread ensures <±2% current matching across temperature; −100 nA I_CBO minimizes leakage error at 85 °C.

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
BC807-40X	Same DFN2020D-3 package; h_FE = 250–600; V_CEO = −45 V; I_C = −500 mA (lower continuous rating)	Higher gain but lower current capacity; less suitable for >500 mA linear regulation	Select when precise low-base-drive switching is prioritized over 1 A load handling.
MBT3906DW1T3G	SOT-363 package; dual PNP; V_CEO = −40 V; I_C = −200 mA per device; not AEC-Q101 qualified	Smaller footprint but no automotive qualification; limited thermal performance due to non-exposed pad	Choose only for non-automotive consumer applications where dual-device integration offsets board area penalty.

Compared with BC807-40X and MBT3906DW1T3G, BC51PASX uniquely combines 1 A continuous current, AEC-Q101 qualification, and ultra-thin thermally enhanced packaging - making it the sole option for automotive high-side switches requiring both robustness and space efficiency.

Availability

BC51PASX is available at Aetrix Electronics and suitable for automotive power management, battery-powered IoT sensors, and compact MOSFET driver circuits requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for BC51PASX 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-enhancing components, with leadership in logic, discrete, and MOSFET technologies for automotive, industrial, and mobile markets.

BC51PASX belongs to the BC51xPAS series of AEC-Q101-qualified PNP transistors designed specifically for high-reliability, space-constrained power switching in automotive body electronics and industrial control modules.

FAQ

What is the maximum allowable junction temperature for BC51PASX?

The absolute maximum junction temperature (T_j) is 150 °C, as defined in the Absolute Maximum Ratings table. Operation beyond this limit risks permanent degradation of h_FE, leakage current, and bond wire integrity. Derating curves in Figure 1 confirm usable power drops to zero at 150 °C ambient on standard FR4 layouts.

Does BC51PASX require a heatsink in typical 1 A switching applications?

No external heatsink is required if PCB layout follows Nexperia's recommended footprint (Figure 12) with ≥1 cm² copper area connected to the exposed collector pad. Under those conditions, R_th(j-a) = 76 K/W limits junction rise to ~125 °C at 1.65 W dissipation - within safe margin below 150 °C T_j.

How does the side-wettable flank (SWF) feature improve manufacturing yield?

SWF enables automated optical inspection (AOI) of solder fillet geometry on all three terminals without X-ray. This detects insufficient solder, bridging, or misalignment in real time during SMT line operation - reducing field failure rates in high-volume automotive assembly where solder joint reliability is critical.

Can BC51PASX replace BC557 in existing SOT23-based designs?

No - BC51PASX uses DFN2020D-3 (SOT1061D), which is not pin-compatible or footprint-compatible with SOT23. While both are PNP transistors, the package change requires PCB redesign, stencil revision, and requalification. Direct replacement is not feasible without hardware modification.

BC51PASX Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

Package/Case:: 3-UDFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Active

Transistor Type:: PNP

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

Voltage - Collector Emitter Breakdown (Max):: 45 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:: 420 mW

Frequency - Transition:: 145MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: DFN2020D-3

BC51PASX FAQ

1.How can I place an order for BC51PASX through Aetrix?

Please submit a Request for Quotation (RFQ) for BC51PASX 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 BC51PASX reliable?

The price and inventory of BC51PASX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC51PASX is usually 5 days.

3.What payment methods are accepted for BC51PASX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC51PASX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC51PASX?

BC51PASX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC51PASX 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 BC51PASX?

For technical support, including BC51PASX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC51PASX requirements.

6.How does Aetrix verify that BC51PASX is sourced from the original manufacturer or authorized distributors?

All BC51PASX 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 BC51PASX meets industry standards.

7.What is the process for return or replacement of BC51PASX?

All BC51PASX units undergo pre-shipment inspection (PSI). If there is an issue with BC51PASX, 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 BC51PASX part is unused and in its original packaging.

Return procedure for BC51PASX:

1.Submit a request within 90 days.

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

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