NXP Semiconductors BBY40,235

Overview

BBY40,235 from NXP Semiconductors is a VHF variable capacitance diode (varactor) fabricated in planar technology and housed in an SOT23 plastic SMD package. It delivers C_d = 26–32 pF at 3 V, 4.3–6 pF at 25 V, and a capacitance ratio of 5–6.5, enabling precise electronic tuning in VHF television tuners up to 160 MHz.

For engineers reviewing the BBY40,235 datasheet, BBY40,235 pinout, BBY40,235 application, or BBY40,235 equivalent, key selection criteria include reverse voltage range (0–30 V), low series resistance (≤0.7 Ω at 200 MHz), temperature-stable capacitance behavior, and SOT23 footprint compatibility for high-density VHF front-end designs.

Technical Context

The BBY40,235 operates as a voltage-controlled capacitor where junction capacitance varies inversely with applied reverse bias. Its planar construction ensures reproducible C_V characteristics across the 3–25 V tuning range, with typical capacitance temperature coefficient below 100 ppm/K.

Designed specifically for band A VHF TV tuners, it supports stable resonance tracking under thermal drift and exhibits minimal reverse leakage (<10 nA at 28 V, 25 °C) to preserve Q-factor in LC tank circuits.

Key Specifications

Pinout & Package

Package: SOT23 (TO-236AB), surface-mount, 3-lead plastic package with standard footprint (D = 3.0 mm, E = 2.8 mm, L_p = 1.4 mm). Marking code: S2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BBY40,235, BBY52,215 offers higher initial capacitance but narrower tuning range, while SMV1232–011 delivers superior RF performance and manufacturability at the cost of non-interchangeable packaging - both require layout review before substitution.

Availability

BBY40,235 is available at Aetrix Electronics and suitable for VHF television tuners, FM radio receivers, and VHF oscillator calibration requiring stable component supply and long-term obsolescence support.

Supply support for BBY40,235 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 delivering high-performance mixed-signal and standard products, with leadership in RF, analog, and interface technologies.

The BBY40,235 belongs to NXP's discrete RF varactor family, engineered specifically for analog VHF tuning systems where linearity, thermal stability, and SMT manufacturability are critical.

FAQ

What is the maximum reverse voltage rating for BBY40,235?

The BBY40,235 has a continuous reverse voltage rating of 30 V, as specified in its Absolute Maximum Ratings table. This value provides a 2 V safety margin above the 28 V test condition used for reverse current characterization. Operating beyond 30 V risks permanent junction damage. The BBY40,235 must be biased exclusively in reverse mode during tuning operation to maintain capacitive behavior and avoid forward conduction.

How does the capacitance ratio of BBY40,235 affect VHF tuner design?

The BBY40,235 exhibits a capacitance ratio of 5–6.5 between 3 V and 25 V, directly determining the achievable frequency tuning range in LC resonant circuits. A ratio ≥5 enables full coverage of VHF band A (47–160 MHz) without switched capacitor banks. This ratio is measured at 1 MHz and remains valid across the VHF band due to the device's low series resistance (≤0.7 Ω), ensuring minimal deviation in practical tuner implementations using the BBY40,235.

Is BBY40,235 suitable for use in FM radio applications?

Yes, the BBY40,235 is suitable for 88–108 MHz FM radio receiver tuning. Its capacitance range (4.3–32 pF), low series resistance (≤0.7 Ω at 200 MHz), and stable C–V linearity support high-Q tank performance in FM front-ends. The BBY40,235 has been historically deployed in broadcast receiver designs meeting IEC 60268 standards, and its thermal coefficient ensures minimal drift across typical indoor operating temperatures.

What is the significance of the "S2" marking on BBY40,235?

The "S2" marking on the BBY40,235 indicates its manufacturer-specific top-side laser marking code per NXP's SOT23 package standard. It identifies the device as the BBY40 variant within the SOT23 outline and confirms compliance with the 1996 product specification. This marking is used for traceability and visual verification during assembly and inspection - the BBY40,235 must be distinguished from functionally similar but electrically distinct variants like BBY41 or BBY52, which carry different codes.

Does BBY40,235 require derating at elevated temperatures?

Yes, BBY40,235 reverse current increases with junction temperature: from ≤10 nA at 28 V and 25 °C to ≤200 nA at 28 V and 85 °C. While the device remains functional up to +125 °C junction temperature, designers must ensure bias networks maintain adequate isolation and that thermal management prevents sustained operation near T_j limits. The BBY40,235's capacitance temperature coefficient is characterized in Fig.4 and remains within ±100 ppm/K across its operating range.