NXP Semiconductors BA591,115

Overview

The BA591 from NXP Semiconductors is a planar high-performance band-switching diode in the SOD323 (SC-76) surface-mount package, featuring 1.05 pF max diode capacitance at 1 V reverse bias, 0.7 Ω max forward resistance at 10 mA, and AEC-Q101 qualification for automotive tuner applications.

For engineers reviewing the BA591 datasheet, BA591 pinout, BA591 application, or BA591 equivalent, key selection criteria include low-capacitance switching for VHF TV tuners, thermal resistance of 120 K/W, junction temperature range of –65 °C to +150 °C, and cathode-marked SOD323 footprint compatibility.

Technical Context

The BA591 operates as a voltage-controlled RF switch in band-selection circuits, leveraging its low series inductance (2 nH) and sub-1 pF capacitance to minimize signal loss and phase distortion at VHF frequencies. Its planar construction ensures stable junction characteristics under thermal cycling.

Designed for DC-biased RF path switching, it supports continuous forward current up to 100 mA and reverse voltage up to 35 V, with reverse leakage limited to 20 nA at 20 V - enabling reliable operation in high-isolation tuner front-ends.

Key Specifications

Pinout & Package

Package: SOD323 (SC-76), plastic surface-mounted, 2-lead, cathode marked with bar on top surface.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar band-switching diode applications.

Compared with BAV99,115 and MMBD7000LT1G, the BA591 delivers superior VHF band-switching performance through lower capacitance and resistance, plus mandatory AEC-Q101 validation - making it the only option qualified for automotive digital TV receiver front-ends requiring stable RF isolation across temperature.

Availability

The BA591 is available at Aetrix Electronics and suitable for VHF television tuners, automotive digital TV receivers, and surface-mount band-switching circuits requiring stable component supply across production lifecycles.

Supply support for BA591 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 consumer applications.

The BA591 belongs to NXP's high-frequency discrete diode product line, engineered specifically for low-loss RF band selection in broadcast tuner systems operating up to 230 MHz.

FAQ

What is the maximum reverse voltage rating for the BA591?

The BA591 has a maximum continuous reverse voltage (VR) rating of 35 V, as specified in the Absolute Maximum Ratings table. This rating applies under standard operating conditions and must not be exceeded to prevent permanent device damage. The BA591 is designed for use in tuner circuits where bias voltages remain within this limit, and its 35 V rating provides margin against transients in VHF front-end applications.

Is the BA591 suitable for automotive applications?

Yes, the BA591 is AEC-Q101 qualified, confirming its reliability for automotive use including temperature cycling, mechanical shock, and humidity testing. It is explicitly intended for automotive digital TV receivers and other vehicle-mounted broadcast tuner systems. The BA591's junction temperature range of –65 °C to +150 °C and thermal resistance of 120 K/W support operation in demanding under-dash environments.

What does the marking "A1" indicate on the BA591 package?

"A1" is the manufacturer's marking code for the BA591, laser-etched or printed on the top surface of the SOD323 package. The bar adjacent to the marking identifies Pin 1 as the cathode, per the simplified outline in the datasheet. This marking enables visual and automated optical inspection during PCB assembly, ensuring correct orientation of the BA591 in high-volume SMT processes.

How does the BA591's diode capacitance affect VHF tuner performance?

The BA591's diode capacitance - max 1.05 pF at 1 V reverse bias - directly determines RF insertion loss and isolation in VHF band-switching paths. At 174–230 MHz, this low capacitance minimizes capacitive loading on antenna traces, preserving signal amplitude and phase fidelity. Lower capacitance also improves off-state isolation, critical for preventing inter-band crosstalk in dual-VHF tuner architectures using the BA591.

What is the thermal resistance specification for the BA591?

The BA591 has a thermal resistance from junction to solder point (Rth(j-sp)) of 120 K/W, measured under standard SMD reflow conditions. This value defines how much the junction temperature rises above the solder point temperature per milliwatt of dissipated power. For example, at 50 mW dissipation, junction temperature increases by 6 °C above the solder point - a key parameter for thermal design in enclosed tuner modules where the BA591 operates near its 500 mW total power limit.