NXP Semiconductors BB184,135

Overview

BB184 from NXP Semiconductors is a UHF low-voltage variable capacitance diode (varactor) fabricated in planar technology and housed in the SOD523 (SC-79) ultra-small SMD package. It delivers a typical capacitance ratio of 7:1 (14 pF at 1 V to 2 pF at 10 V), exhibits steep CV curve response, and supports reverse voltage up to 13 V - enabling precise tuning in compact RF front-ends.

For engineers reviewing the BB184 datasheet, BB184 pinout, BB184 application, or BB184 equivalent, key selection considerations include its 1.25 mm × 0.85 mm footprint, cathode-marked polarity, sub-1 Ω series resistance at 470 MHz, and guaranteed capacitance matching ≤2% across 5-diode sequences.

Technical Context

The BB184 operates exclusively under reverse bias, where junction capacitance varies nonlinearly with applied voltage - optimized for high-Q resonant circuits. Its planar construction ensures stable temperature coefficient performance and tight unit-to-unit capacitance matching.

Designed for UHF tuning applications, it maintains low reverse leakage (≤10 nA at 10 V, 25 °C) and operates reliably from −55 °C to +125 °C junction temperature. The diode's 0.65 Ω typical series resistance at 470 MHz directly supports low insertion loss in VCO tank networks.

Key Specifications

Pinout & Package

Package: SOD523 (SC-79), ultra-small surface-mount plastic package (1.25 mm × 0.85 mm × 0.65 mm); cathode indicated by marking bar.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BB204,115 and SMV1232-011, the BB184 offers optimal balance of UHF tuning range, miniaturization, and production matching - making it the preferred choice for cost-sensitive, space-constrained consumer TV and RFID applications where 13 V operation suffices.

Availability

BB184 is available at Aetrix Electronics and suitable for voltage-controlled oscillators, low-voltage TV tuners, UHF RFID readers, and ISM band transceiver calibration requiring stable component supply and consistent parametric performance across production lots.

Supply support for BB184 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 BB184 belongs to NXP's discrete RF varactor family, engineered specifically for UHF tuning in low-voltage, miniaturized broadcast and wireless infrastructure equipment - emphasizing capacitance linearity, thermal stability, and high-volume manufacturability.

FAQ

What is the maximum reverse voltage rating for BB184?

The BB184 has a continuous reverse voltage rating of 13 V, as specified in its Absolute Maximum Ratings table. Exceeding this voltage risks permanent junction damage. This rating supports common low-voltage RF systems operating from 3.3 V or 5 V supplies with modest tuning headroom. The BB184 must never be forward-biased during normal operation.

How does BB184's capacitance ratio compare to other NXP varactors?

The BB184 delivers a typical capacitance ratio of 7:1 (Cd(1 V)/Cd(10 V)), which is steeper than BB204,115 (5.5:1) and comparable to BB179 variants. This ratio directly enables broader frequency coverage in single-loop VCOs. The BB184's ratio is measured at 1 MHz and remains stable across its rated temperature range.

Is BB184 suitable for automotive applications?

No - the BB184 is not automotive-qualified. NXP explicitly states in its datasheet that non-automotive qualified products like the BB184 are neither tested nor warranted for automotive use. For automotive-grade varactors, consider NXP's AEC-Q200 qualified alternatives such as the BBY52 series, which undergo extended temperature and reliability validation.

What does the "A2" marking on BB184 indicate?

The "A2" marking on the BB184 device body is the manufacturer's identification code per NXP's ordering information table. It corresponds exclusively to the BB184 type number and confirms the SOD523 package variant. The marking bar adjacent to pin 1 denotes the cathode terminal, critical for correct reverse-bias orientation in circuit layout.

Can BB184 replace BB179 in existing designs?

BB184 is not a direct replacement for BB179 due to differences in capacitance profile and packaging: BB179 uses SOD-323, while BB184 uses SOD523. Though both are UHF varactors, BB184 offers higher capacitance at 1 V (14 pF vs. BB179's ~10 pF) and a steeper CV curve. PCB layout and bias network recalibration would be required.