Nexperia USA Inc. BC55PASX

Overview

BC55PASX from Nexperia is an NPN medium power transistor in a DFN2020D-3 (SOT1061D) leadless package, rated for 60 V V_CEO, 1 A continuous collector current, and 2 A peak pulse current. It delivers h_FE of 63–250 at I_C = 150 mA, features exposed thermal pad for enhanced heat dissipation, and is optimized for high-side switching and MOSFET driver stages in compact power management circuits.

For engineers reviewing the BC55PASX datasheet, BC55PASX pinout, BC55PASX application, or BC55PASX equivalent, this device is selected for linear voltage regulators, battery-powered systems, and amplifier stages where low-profile SMD packaging, AOI-compatible side-wettable flanks, and stable DC current gain across temperature are critical design requirements.

Technical Context

This NPN bipolar junction transistor operates in active, saturation, and cutoff regions with defined V_CE(sat) ≤ 500 mV at I_C = 500 mA / I_B = 50 mA and V_BE ≤ 1 V under same conditions. Its f_T of 100–180 MHz supports moderate-frequency switching up to several tens of MHz in driver applications.

Thermal performance is configuration-dependent: R_th(j-a) ranges from 76 K/W (4-layer PCB + 1 cm² collector pad) to 298 K/W (single-layer standard footprint), enabling precise thermal budgeting in space-constrained designs. The ultra-thin 0.65 mm profile and side-wettable flanks support automated optical inspection and reliable reflow soldering per IPC-7351B.

Key Specifications

Pinout & Package

BC55PASX is housed in a thermally enhanced DFN2020D-3 (SOT1061D) package: 2.0 mm × 2.0 mm × 0.65 mm body, leadless construction with side-wettable flanks and exposed thermal pad on underside. The package supports high-density placement and efficient heat transfer to PCB copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC54PASX and BC817-40DW, BC55PASX uniquely balances 60 V rating, 1 A continuous current, and DFN2020D-3 thermal performance-making it the only option among the three qualified for high-side switching in 48 V battery systems with AOI-verified assembly.

Availability

BC55PASX is available at Aetrix Electronics and suitable for linear voltage regulators, battery-driven devices, and MOSFET driver circuits requiring stable component supply, long-term manufacturability, and RoHS-compliant leadless packaging.

Supply support for BC55PASX 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 including logic, discrete, and MOSFET devices, serving automotive, industrial, and consumer markets with high-volume manufacturing excellence.

BC55PASX belongs to the BC55xPAS series of medium-power NPN transistors designed specifically for space-constrained, thermally demanding applications such as power management and interface driver stages in portable and industrial electronics.

FAQ

What is the maximum allowable junction temperature for BC55PASX?

The absolute maximum junction temperature (T_j) for BC55PASX is 150 °C, as specified in the limiting values table. Operation above this temperature risks permanent degradation of electrical parameters and bond wire integrity. Thermal design must ensure T_j remains below 150 °C under worst-case ambient and power dissipation conditions, using appropriate PCB copper area and layer count per the published R_th(j-a) data.

Does BC55PASX support automatic optical inspection (AOI) of solder joints?

Yes-BC55PASX features side-wettable flanks in its DFN2020D-3 package, enabling reliable AOI detection of solder fillet quality without requiring X-ray inspection. This is confirmed in Section 2 of the datasheet under "Features and benefits" and validated by IPC-7351B-compliant footprint dimensions in Figure 12, making it suitable for high-yield, high-reliability SMT production lines.

How does the h_FE variation affect base resistor selection in switching applications?

With h_FE ranging from 63 to 250, base resistor value must ensure saturation across the full gain spread: for I_C = 1 A, minimum I_B = I_C/h_FE(min) = 15.9 mA. Using V_BE ≈ 0.85 V and 3.3 V GPIO, R_B ≤ (3.3 V − 0.85 V)/15.9 mA ≈ 154 Ω. A 120 Ω resistor guarantees hard saturation even at lowest h_FE, preventing excessive V_CE(sat) and thermal stress.

Is BC55PASX qualified for automotive applications?

No-BC55PASX is explicitly marked as non-automotive qualified in the revision history (Section 13), which states "Product(s) changed to non-automotive qualification" in v.3 (20241009). It lacks AEC-Q101 stress testing and automotive-grade reliability screening. For automotive use, Nexperia recommends consulting their -Q qualified alternatives listed on nexperia.com, such as BC55PASX-Q.