Anritsu MS2802A RF LPF switch board reverse engineering

[liamkinne]

I'm repairing an MS2802A that I picked up cheap off ebay a few years back. When it arrived, it was missing the 10MHz reference and the control board for some RF switches that is attached to that. I'm looking to replicate the switch control board based off the schematic in the service manual. The 10MHz reference itself I will deal with later since I can just use an external source from now.

The schematics for the RF switch board list an IC referenced as "Z1" and the part number "UL2". I've tried looking around for a similar part, even a discontinued one, but not found anything useful. Does anyone here have any insight into what this part could be?

I've attached the relevant service manual pages and some pictures of the switches themselves.

[RFDx]

UL2 is used as a driver delivering complementary +/-5V outputs for the two SPDT PIN-diode switches. I don't think you are gonna find the UL2 IC so you probably will have to design your own driver:

https://www.analog.com/en/resources/analog-dialogue/articles/driving-pin-diodes-with-op-amps.html

The MADR-007097 from MACOM is made for this purpose but it's rather expensive and you would need two:

https://www.macom.com/products/product-detail/MADR-007097-000100

[liamkinne]

That MACOM part doesn't look too bad of a price. $30AUD/ea is probably worth it rather than spending too long coming up with an op-amp based circuit.

I'm going to probe the control signals a bit and then get started on a PCB design.