NXP Semiconductors BAP51LX,315

Overview

BAP51LX from NXP Semiconductors is a silicon PIN diode in a DFN1006D-2 (SOD882D) surface-mount package, designed for RF signal switching and attenuation up to 3 GHz. It delivers 0.17 pF typical diode capacitance at 5 V reverse bias, 1.4 Ω typical forward resistance at 10 mA, and AEC-Q101 qualification for automotive-grade reliability.

For engineers reviewing the BAP51LX datasheet, BAP51LX pinout, BAP51LX application, or BAP51LX equivalent, key selection criteria include RF isolation (>13 dB at 2.45 GHz), ultra-low series inductance (0.4 nH), low forward voltage (0.95 V typ. at 50 mA), and compatibility with high-frequency PCB layouts requiring minimal parasitic effects.

Technical Context

The BAP51LX operates as a current-controlled RF switch: forward bias reduces r_D to sub-ohm levels for low-loss conduction, while reverse bias maximizes C_d depletion and isolation. Its intrinsic layer enables fast carrier lifetime (0.55 μs) and stable performance across 900 MHz–2.45 GHz bands.

Designed for series-switch topologies in 50 Ω systems, it achieves ≤0.12 dB insertion loss at 2.45 GHz under 100 mA bias and >13 dB isolation at zero bias - critical for LTE/Wi-Fi front-end modules where linearity and harmonic suppression are essential.

Key Specifications

Pinout & Package

Package: DFN1006D-2 (SOD882D), leadless ultra-small plastic SMD package; body dimensions 1.0 × 0.6 × 0.4 mm; cathode indicated by marking bar.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BAR50-02V and NSVRB510MUTBG, the BAP51LX offers superior 2.45 GHz isolation and lower parasitic inductance in the smallest standard footprint - making it optimal for miniaturized, high-efficiency RF switches where board area and frequency margin are critical.

Availability

BAP51LX is available at Aetrix Electronics and suitable for cellular front-end switching, Wi-Fi antenna tuning, and automotive RKE systems requiring stable component supply and AEC-Q101 compliance.

Supply support for BAP51LX 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 headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and mobile applications.

The BAP51LX belongs to NXP's high-frequency discrete diode product line, engineered specifically for RF signal routing and attenuation in compact wireless infrastructure and automotive telematics systems.

FAQ

What is the maximum operating frequency supported by the BAP51LX?

The BAP51LX is characterized for operation up to 3 GHz, with verified performance metrics including 13 dB isolation at 2.45 GHz and <0.12 dB insertion loss at the same frequency under 100 mA forward bias. Its 0.4 nH series inductance and 0.17 pF capacitance support stable S-parameter behavior through the upper LTE and Wi-Fi bands. The BAP51LX datasheet confirms functionality across 900 MHz, 1800 MHz, and 2450 MHz bands with measured data.

Does the BAP51LX require external bias circuitry for RF switching applications?

Yes, the BAP51LX requires a DC bias network to control its ON/OFF state: forward bias (anode positive relative to cathode) lowers r_D for conduction, while reverse bias maximizes C_d depletion for isolation. A typical implementation uses a series RF choke and shunt capacitor to inject bias without disturbing the RF path. The BAP51LX itself contains no integrated bias control circuitry - it functions as a passive, current-controlled RF element.

Is the BAP51LX pin-compatible with other SOD882D-packaged PIN diodes?

The BAP51LX uses standard SOD882D pinout (cathode at Pin 1, anode at Pin 2), matching industry-standard footprints such as those used by BAR50-02V and NSVRB510MUTBG. However, electrical performance differs significantly - the BAP51LX delivers lower capacitance and higher isolation. PCB layout reuse is possible, but system-level validation of RF performance is required when substituting.

What thermal derating applies to the BAP51LX at elevated ambient temperatures?

The BAP51LX has a thermal resistance R_th(j-sp) of 66 K/W from junction to solder point. At T_sp = 90 °C, total power dissipation is limited to 140 mW. For continuous 100 mA operation (producing ~0.09 W at 0.9 V), ambient temperature must remain below ~80 °C to maintain T_j ≤ 150 °C. Derating curves in the BAP51LX datasheet show linear reduction of P_tot above 90 °C solder point temperature.

How does AEC-Q101 qualification impact the use of BAP51LX in non-automotive designs?

AEC-Q101 qualification certifies the BAP51LX for extended temperature cycling (−65 °C to +150 °C), mechanical shock, and humidity exposure - benefits that directly improve long-term reliability in industrial and consumer RF modules. While not required outside automotive, this qualification provides design margin for harsh environments, such as outdoor IoT gateways or factory-floor wireless sensors. The BAP51LX leverages the same process and screening as automotive-grade parts, enhancing field failure resilience regardless of end application.