FSD273TA

Overview

The FSD273TA is a silicon hyperabrupt varactor diode from the Zetex 950 series, manufactured by Diodes Incorporated. It serves as a band-selected version of the ZMDC953 dual varactor, available in SOD-523 surface-mount packages. The device features closely controlled capacitance-voltage characteristics and low reverse current for high Q performance at low voltages. Electrical specifications include a maximum reverse voltage of 12 V and typical leakage of 10 pA. Capacitance bands are defined at VR=1.5V: Band A (30.0–32.5 pF), Band B (32.3–34.7 pF), and Band C (34.5–37.0 pF).

Feature Summary

• Band-selected capacitance ranges for DAB applications
• Low reverse current ensuring very low phase noise
• High Q factor at low operating voltages

Applications

• VCXO and TCXO circuits
• Wireless communications systems
• Digital Radio receivers

Procurement Notes

Verify the specific capacitance band required for the design, as availability depends on manufacturing processes. Confirm package type matches the SOD-523 footprint. Ensure supply chain documentation aligns with Diodes Incorporated standards for this component.

Selection Notes

Select based on required capacitance tolerance and tuning range. Verify compatibility with 3-volt system control voltages. Check thermal dissipation requirements against ambient temperature conditions.

Part Context

This part belongs to the 950 series of silicon low voltage hyperabrupt varactor diodes. It is functionally equivalent to the ZMDC953 but supplied in pre-defined capacitance bands rather than loose tolerances.

Replacement Considerations

Direct substitutes include ZMDC953TA or other 950 series variants like ZV953V2TA if loose capacitance tolerances are acceptable. Verify pinout and package dimensions match SOD-523.

FAQ

What is the difference between FSD273TA and ZMDC953?

FSD273TA is a band-selected version of the ZMDC953, offering tighter capacitance ranges (Bands A, B, or C) compared to the standard loose tolerance of the ZMDC953.

Can I specify a particular capacitance band when ordering?

No, customers cannot specify a particular band because availability is process-dependent. Shipments may contain reels of different bands.