Multiband radios need a way to route one common port to any of several paths, and the switching device in that position has a large influence on overall performance. The PE42441E-Z from pSemi is an SP4T absorptive RF switch built on the UltraCMOS process and specified from 10 MHz to 8 GHz in a 32-LGA package. This guide explains what absorptive switching buys you and how to judge a switch for a multiband front end.
Absorptive versus reflective
A reflective switch leaves its unused ports open, so they present a poor match and reflect the signal that reaches them. An absorptive switch terminates those ports into the system impedance, so the mismatch stays low and reflections are absorbed rather than returned to the signal path. That difference matters most when several switches are chained, when a port feeds a sensitive receiver, or when transient behaviour during switching can disturb the rest of the system.
Reading the switch specification
- Insertion loss — the signal lost in the selected path; lower is better, and it varies with frequency.
- Isolation — how much signal leaks into the unselected paths; this sets how cleanly you can separate bands.
- Control logic — the number and polarity of control lines must match the logic and voltage you have.
- Switching and settling — how fast the switch changes state and how the transient behaves; important in time-division systems.
Where an SP4T absorptive switch fits
The four-path topology suits filter banks, antenna selection, multiband front ends and instrument signal routing, where a single common port needs to reach one of four branches. Because the part covers a wide frequency span in one device, it can serve several bands without a dedicated switch for each. Confirm the key figures at your operating band, and confirm every rating against the manufacturer datasheet before design-in.
RF switches and components we stock
| Part | Function | Package | Link |
|---|---|---|---|
| PE42441E-Z | SP4T absorptive RF switch, 10 MHz - 8 GHz (pSemi) | 32-LGA | PE42441E-Z |
| PE42551-52 | RF switch (pSemi) | LGA | PE42551-52 |
| PE42540G-Z | RF switch (pSemi) | LGA | PE42540G-Z |
| RFSW6042TR7 | SPDT RF switch (Qorvo) | QFN | RFSW6042TR7 |
| MASWSS0169TR-3000 | GaAs SPDT switch (MACOM) | SOT-26 | MASWSS0169TR-3000 |
See the pSemi range and the wider interface / RF chip range. Send your frequency band, topology and quantity for a quote.
Frequently asked questions
What does 'absorptive' mean for an RF switch?
An absorptive switch terminates the unused ports into the characteristic impedance, typically 50 ohms, instead of leaving them open. That keeps the mismatch low and stops reflections bouncing back into the signal path, which is why absorptive switches are preferred where several paths are combined and switching transients matter.
When do I need SP4T rather than SP2T?
SP4T gives four selectable paths from one common port, so a single device can route one antenna or source to any of four destinations. It is the usual choice for multiband front ends, filter banks and test paths where you want to switch between several branches without cascading smaller switches.
What parameters decide whether a switch fits my design?
Insertion loss sets how much signal you lose in the chosen path; isolation sets how much leaks to the paths you did not select; the control interface has to match your logic; and the supply and switching speed must suit the rest of the system. Always confirm each figure at the frequency band you actually use, because switch performance varies across the band.
Do you stock PE42441E-Z and other pSemi switches?
Yes. We stock the PE42441E-Z and other pSemi UltraCMOS switches, and we can quote by quantity with date codes so you can validate before committing to volume.
Recommended next steps
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- Browse related in-stock lines: pSemi · Interface / RF Chips.
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About us & trademarks: JTDZ Tech (Shenzhen Jingteng Electronics Technology Co., Ltd.) is an independent distributor of electronic components. We are not an authorised distributor or representative of the manufacturers named in this article. Manufacturer and part names are used for indicative purposes only, to help identify the components discussed; all trademarks remain the property of their respective owners. Always verify specifications against the manufacturer's datasheet before design-in or purchase.
