Hi，
We are designing a cellular antenna based on the Thingy91x reference, which needs to support all frequency bands of the nRF9151 cellular module. The antenna tuning switch QM13345, which uses an MIPI interface and must be compatible with the internal firmware driver of the nRF9151, has been discontinued. Are there any recommended alternative tuning switch models available?
By the way, does thingy91_mfw-1.3.7_sdk-2.8.0.zip this sample have source code ？
Hello, I’m in the same boat. I love the new active antenna tuning strategy on the Thingy91:X — it’s a huge step forward. But I have to say, I was disappointed to see Qorvo again! They’re such a pain to work with: you have to request the datasheet, and you can’t actually buy the parts unless you’re ordering in volume. I’d argue that this part isn’t really “available” at all.
That said, the RFFE-based tuning strategy is much faster and lower power than the old MAGPIO approach, and it gives a lot more flexibility. However, Nordic doesn’t really explain what’s going on between the nRF9151 and the QM13345, and that matching circuit looks like fresh hell.
I considered swapping in a Skyworks RFFE-controlled antenna switch, but then I noticed something interesting buried in the Thingy91X board files:
config MODEM_ANTENNA_AT_MIPIRFFECTRL_ON default "AT%XMIPIRFFECTRL=1,1,1,28,56,13,0,0,8,8,715,4,4,770,12,12,829,11,11,863,130,130,892,1,1,939,129,129,978,26,26,1042,8,8,1118,4,4,1270,12,12,1386,14,14,1523,130,130,2200"
This is an MIPI RFFE command that configures the four-port switch to connect the right matching components. You can see, for example, that 8,8,715 switches in channel RF4 for 715 MHz (0b1000 to the control register). But then there’s 130,130,892 — at 892 MHz it writes 130 (0b10000010) to the control register. There’s a bit beyond the number of ports! Then you see 12 being used at 829 MHz — that’s 0b1100, meaning two RF ports are switched in simultaneously - more hell.
That’s when it clicked: the “antenna switch” QM13345 isn’t just a switch at all — it’s actually an antenna tuner. It can shunt any of its RF ports to ground, dynamically shaping the impedance network, making an array of possible outcomes.
A bit of digging later, I found the exact paper that explains everything — authored by Ignion themselves:
Reconfigurable Antenna Booster System for Multiband Operation in IoT Devices With an SP4T Switch
It’s mind-blowing — it details the crazy switching logic, the matching networks, and the design reasoning behind it all. Once you read it, the Thingy91X schematic suddenly makes sense!
Even better, I’ve found a drop-in, available alternative: the Infineon BGSA147ML10. It does everything the QM13345 does, and you can actually buy it from Mouser right now. We might need to tweak the AT%XMIPIRFFECTRL command slightly, but we’ll find out soon enough.
That paper explains everything.
Happy Tuesday!
