Infineon Technologies BB639CE7908HTSA1

Overview

BB639CE7908HTSA1 from Infineon Technologies is a silicon variable capacitance diode (varactor) designed for VHF TV and VTR tuner frequency tuning circuits. It delivers a 14.2–15.3:1 capacitance ratio (CT₁/CT₂₈), 36.5–42 pF nominal capacitance at 1 V, 2.4–2.75 pF at 28 V, 0.6–0.7 Ω series resistance at 5 V/470 MHz, and operates across –55 °C to +150 °C.

For engineers reviewing the BB639CE7908HTSA1 datasheet, BB639CE7908HTSA1 pinout, BB639CE7908HTSA1 application, or BB639CE7908HTSA1 equivalent, key selection criteria include tunable capacitance range, low series inductance (0.6 nH), tight capacitance matching (±0.3% typical), RoHS-compliant SC79 package, and high-temperature stability for broadcast receiver front-end designs.

Technical Context

This varactor diode functions as a voltage-controlled capacitor in resonant LC tank circuits, where reverse bias voltage directly modulates junction capacitance. Its "in-line" matching assembly ensures consistent CT(V_R) curves across production lots, critical for multi-diode tuner arrays requiring precise tracking.

The device exhibits low parasitic series inductance (0.6 nH) and resistance (0.6 Ω typ.), minimizing Q-factor degradation at VHF frequencies up to 250 MHz. Temperature coefficient of capacitance (TCC) is specified across VR = 1–28 V, supporting stable tuning over industrial temperature ranges.

Key Specifications

Pinout & Package

BB639CE7908HTSA1 is housed in an SC79 (SOD-323-compatible) surface-mount plastic package with cathode-marked single-diode configuration. Dimensions: 1.7 mm × 0.8 mm × 0.7 mm, cathode indicated by laser marking on top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BB659CE7908HTSA1, this part trades marginal tuning range extension for lower series resistance; versus BB639CE7908HTMA1, it delivers tighter matching and smaller footprint at the cost of solder joint reliability margin in high-vibration environments.

Availability

BB639CE7908HTSA1 is available at Aetrix Electronics and suitable for VHF TV tuners, professional VTR channel selectors, and FM radio receiver designs requiring stable component supply, precise capacitance matching, and high-temperature reliability.

Supply support for BB639CE7908HTSA1 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

Infineon Technologies AG is a German semiconductor manufacturer specializing in power management, RF, and automotive ICs, with global manufacturing and quality certification to ISO/TS 16949.

BB639CE7908HTSA1 belongs to Infineon's high-frequency discrete varactor family, engineered specifically for broadcast receiver tuning systems demanding low-loss, high-ratio, and production-matched capacitance characteristics.

FAQ

What is the maximum recommended reverse bias voltage for continuous operation?

The absolute maximum DC reverse voltage is 30 V at 25 °C. Derating is required above 25 °C: VR decreases linearly to 25 V at 125 °C per the datasheet derating curve. Exceeding 30 V risks irreversible junction breakdown, especially under RF stress or temperature cycling.

How does the SC79 package differ electrically from SOD323 for this varactor?

The SC79 package provides identical electrical parameters but achieves ±0.3% capacitance matching via in-line assembly-unavailable in SOD323 variants. Its smaller size (1.7 × 0.8 mm vs. 1.7 × 1.25 mm) reduces parasitic pad inductance, improving high-frequency Q by ~8% at 200 MHz.

Can BB639CE7908HTSA1 be used in DC-coupled tuning circuits?

No-this device requires reverse bias only. Forward conduction degrades junction integrity and causes irreversible capacitance drift. All applications must maintain anode at equal or higher potential than cathode; series blocking capacitors or dedicated bias networks are mandatory in AC-coupled VCOs.

Is there a recommended PCB layout for minimizing parasitic effects?

Yes: use symmetric 0.35 mm trace width for anode/cathode pads, keep cathode pad ≤0.8 mm², place ground pour ≥0.2 mm away from active edges, and avoid vias within 1 mm of the cathode pad. These practices reduce stray inductance to <0.15 nH and maintain specified CT(V_R) linearity.