Nexperia USA Inc. BC857AQAZ

Overview

BC857AQAZ from Nexperia is a PNP general-purpose bipolar junction transistor in a leadless DFN1010D-3 (SOT1215) package, rated for −45 V V_CEO, −100 mA I_C, and offering h_FE = 125–250 at I_C = −2 mA / V_CE = −5 V. It delivers low-profile mounting (0.37 mm height), AEC-Q101 qualification, and AOI-compatible side pads for automotive and space-constrained mobile power management.

For engineers reviewing the BC857AQAZ datasheet, BC857AQAZ pinout, BC857AQAZ application, or BC857AQAZ equivalent, this device supports precise current gain selection, thermal robustness on FR4 PCBs, and reliable switching in low-voltage PNP bias networks - critical for battery-powered sensor interfaces and load control circuits.

Technical Context

This PNP BJT operates with emitter-base forward bias and collector-base reverse bias in standard active or saturation modes. Its DC current gain (h_FE) is binned to 125–250, enabling predictable base drive sizing for fixed-gain switching applications. The device exhibits V_BE = −600 to −750 mV at I_C = −2 mA and V_CE = −5 V, supporting stable bias point design across temperature.

V_CE(sat) remains ≤ −200 mV at I_C = −10 mA / I_B = −0.5 mA, confirming low-loss conduction in saturated switch configurations. Thermal resistance R_th(j-a) is 446 K/W on single-layer FR4 and 284 K/W on 4-layer boards, directly informing derating requirements for continuous operation up to +150 °C junction temperature.

Key Specifications

Pinout & Package

DFN1010D-3 (SOT1215) is a 3-terminal, leadless surface-mount plastic package with visible and solderable side pads, body dimensions 1.1 mm × 1.0 mm × 0.37 mm, and thermal-enhanced construction for improved power handling on standard PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose transistor applications.

Compared with BC857AQAZ, BC857BW trades miniaturization and automotive qualification for broader SMT compatibility, while MMBT3906LT1G offers wider h_FE spread but sacrifices both package compactness and AEC-Q101 validation - making BC857AQAZ optimal for next-gen automotive and mobile designs demanding reliability, size, and process control.

Availability

BC857AQAZ is available at Aetrix Electronics and suitable for automotive body control modules, smartphone power sequencing, industrial sensor conditioning, and USB-C port protection requiring stable component supply across production lifecycles.

Supply support for BC857AQAZ 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 semiconductors, delivering high-performance, reliable components for automotive, industrial, and mobile markets.

The BC857XQA series belongs to Nexperia's AEC-Q101-qualified discrete transistor portfolio, engineered specifically for high-reliability, space-constrained switching and amplification in automotive and portable electronics.

FAQ

Is BC857AQAZ pin-compatible with BC857BQA or BC857CQA?

Yes - all BC857XQA variants share identical DFN1010D-3 (SOT1215) pinout (Base–Emitter–Collector–Collector), same package dimensions, and identical thermal and electrical footprints. Only h_FE binning differs (125–250 for AQA, 220–475 for BQA, 420–800 for CQA), allowing direct substitution where gain tolerance permits.

What is the maximum allowable PCB copper layer count for full-rated P_tot = 440 mW?

The 440 mW total power dissipation rating applies strictly to FR4 PCBs with 4-layer copper, tin-plated, and standard footprint per Nexperia's limiting values table. Using fewer layers (e.g., 1- or 2-layer) reduces P_tot to 280 mW; thermal simulation or empirical testing is required to confirm safe operation beyond these validated conditions.

Does BC857AQAZ support reflow soldering per JEDEC J-STD-020?

Yes - Nexperia specifies compatibility with standard lead-free reflow profiles (peak 260 °C, 30 s max above 217 °C). The DFN1010D-3 package outline and solder land pattern in Figure 18 are aligned with J-STD-020, and side-pad geometry ensures reliable wetting and AOI detectability without voiding or tombstoning.

Can BC857AQAZ replace BC847AQA in existing NPN-based designs?

No - BC857AQAZ is a PNP transistor with inverted polarity (current flows from emitter to collector), whereas BC847AQA is NPN. Direct replacement would invert logic states and likely damage circuitry. A true functional substitute requires redesigning bias networks and signal paths to accommodate PNP topology and complementary gain characteristics.