NXP Semiconductors BAP51-05W,115

Overview

BAP51-05W from NXP Semiconductors is a dual-element silicon PIN diode in common cathode configuration, housed in an SOT323 plastic surface-mount package. It delivers low diode capacitance (0.2 pF at 5 V reverse bias), low forward resistance (1.5 Ω at 10 mA), and AEC-Q101 qualification for automotive RF switching applications.

For engineers reviewing the BAP51-05W datasheet, BAP51-05W pinout, BAP51-05W application, or BAP51-05W equivalent, key selection criteria include its dual-anode common-cathode topology, 50 V reverse voltage rating, 50 mA continuous forward current capability, and RF performance up to 3 GHz with insertion loss below –2.5 dB at 10 mA bias.

Technical Context

The BAP51-05W integrates two independent PIN diodes sharing a single cathode terminal, enabling compact series-shunt RF switch configurations without external interconnects. Its low charge carrier lifetime (550 ns) supports fast RF switching transitions in T/R modules and antenna tuning circuits.

Designed for high-frequency signal routing, it operates with minimal parasitic inductance (1.6 nH) and exhibits stable capacitance across 0–5 V reverse bias (0.2–0.35 pF), making it suitable for broadband matching networks and variable attenuators in 50 Ω systems.

Key Specifications

Pinout & Package

SOT323 plastic surface-mounted package (3-lead, 1.3 × 1.8 mm footprint); JEDEC standard SC-70 outline; thermal pad not present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-PIN diode RF switching applications.

Compared with BAR50-03W and NSVRB5101MUTBG, the BAP51-05W uniquely combines AEC-Q101 qualification, dual-anode integration, and sub-0.25 pF capacitance-enabling smaller, more reliable RF switch designs for automotive and high-density wireless modules without sacrificing broadband performance.

Availability

BAP51-05W is available at Aetrix Electronics and suitable for automotive telematics, cellular front-end modules, and ISM-band transceiver designs requiring stable component supply, long-term lifecycle support, and AEC-Q101-compliant sourcing.

Supply support for BAP51-05W 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

NXP Semiconductors is a global semiconductor company specializing in secure connectivity solutions for automotive, industrial, and mobile applications.

The BAP51-05W belongs to NXP's high-frequency PIN diode product line, engineered specifically for RF switching, attenuation, and antenna tuning in automotive-grade and broadband wireless systems.

FAQ

What is the maximum reverse voltage rating for the BAP51-05W?

The BAP51-05W has a continuous reverse voltage rating of 50 V, as specified in Table 4 of the official NXP datasheet (Rev. 2.1, February 2019). This rating applies under steady-state conditions and must not be exceeded to prevent junction breakdown. The BAP51-05W is designed for RF blocking applications where reverse bias ensures high isolation, and its capacitance remains stable across this voltage range (0.2–0.35 pF).

How does the common-cathode configuration of the BAP51-05W simplify RF switch design?

The common-cathode configuration of the BAP51-05W eliminates the need for external interconnection between cathodes of two discrete PIN diodes, reducing parasitic inductance and PCB routing complexity. In a series-shunt RF switch, Pin 3 serves as the shared DC return and RF ground reference, allowing independent control of each anode (Pins 1 and 2) while maintaining tight coupling and consistent biasing-critical for balanced insertion loss and isolation in BAP51-05W-based designs.

Is the BAP51-05W qualified for automotive applications?

Yes, the BAP51-05W is AEC-Q101 qualified, as explicitly stated in Section 1.2 of the NXP datasheet. This qualification confirms its suitability for automotive environments, including extended temperature operation (–40 °C to +125 °C junction), mechanical shock/vibration resistance, and long-term reliability in under-hood and cabin RF systems such as telematics antennas and radar front-ends.

What is the typical diode capacitance of the BAP51-05W at 5 V reverse bias?

The typical diode capacitance of the BAP51-05W at 5 V reverse bias is 0.2 pF, with a maximum of 0.35 pF, per Table 6 in the NXP datasheet. This low capacitance enables minimal signal loading in VHF through low-microwave bands (up to 3 GHz), supporting broadband impedance matching and high-isolation RF switching without requiring compensating capacitance in BAP51-05W-based circuits.

Can the BAP51-05W be used in UWB applications spanning 3.1–10.6 GHz?

Yes, the BAP51-05W supports UWB applications: Figure 3 in the NXP datasheet shows |S21|² insertion loss below –2.5 dB up to 3 GHz at 10 mA bias, and its low series inductance (1.6 nH) and stable rD vs. frequency behavior enable predictable attenuation control across the full 3.1–10.6 GHz band when operated in variable-resistance mode-making it suitable for pulse shaping and amplitude control in BAP51-05W-based UWB sensor designs.