RF switch performance improved with SPDT switch

25th November 2015

IDT

Jordan Mulcare

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Datasheet

IDT has introduced the industry’s first single-pole, double-throw (SPDT) RF switch featuring its patent-pending K_Z constant impedance technology. The IDT F2923 is a low insertion loss SPDT absorptive RF switch designed for a multitude of RF applications, including base stations (2G, 3G, 4G, 5G), wireless backhaul, CATV and portable handhelds.

The K_Z feature controls all port impedances when switching between RF ports, preserving the return loss. Standard switches without K_Z create a large voltage standing wave ratio (VSWR) transient when switching RF paths because the impedance of the switch is not well controlled during the switching event. A VSWR transient can degrade system performance and reduce reliability. Benefits of Kz in different dynamic or 'hot switching' scenarios include:

Minimising switched Tx/Rx Synthesizer pulling and recovery time in TDD systems
Avoiding damage and error-inducing transients when switching between two RF elements such as PAs, drivers and LNAs.
Minimising transient amplitude and phase error on the unswitched path(s) when switching a path of a distribution network such as a 3dB coupler or 4 way splitter

“With this latest SPDT switch, we highlight our new K_Z technology to dramatically improve hot-switching performance,” said Chris Stephens, General Manager of RF division, IDT. “The F2923 demonstrates yet again IDT’s leadership in the core RF innovations that system developers desire.”

In addition to K_Z technology, the device delivers Insertion loss of only 0.48dB at 2GHz, IIP3 greater than 66dBm at 2GHz and industry-leading isolation of 74 dB at 2 GHz.

Covering a broad frequency range from 300kHz to 8000MHz, IDT’s innovative Kz technology ensures the device delivers near-constant impedance (VSWR < 1.4:1 compared to 9:1 for standard switches) when switching from one RF port to another while not compromising isolation, linearity, or insertion loss. The F2923 uses a single positive supply voltage of 3.3V and supports standard 1.8 and 3.3V control logic levels.