I have assembled the power supplies, clock generator and the Serial Interface (the boring stuff basically) and so far no smoke
All voltages are exactly what they're supposed to be and on monday I'll install the FPGA when I'm at work.
Up to now I have identified the following problems:
- U4_CLK (74LVC74): Footprint a little bit too wide for the chip I ordered. Pin-Pitch is right, so I was able to install it anyway.
- U5_CLK: Ordered the part with the wrong footprint (Ordered PL500-17SC with SOIC-8 Package instead of PL500-17TC in SOT-23 Package). I'll have to install the chip deadbug-style since the PL500-17TC seems to be sold out everywhere.
- U5_LFS, U6_LFS, U7_LFS (Analog supplies for the REFCLK-Parts inside the AD9957): I forgot to order the 1.8V RT9193 Regulators. Don't know why, probably missed them on the list when I ordered. They're not available from Mouser, so I'll have to order from LCSC or Digikey. Until they arrive, I'll just connect the 1.8V from the switch mode converter to the output-pads of these chips. It'll introduce noise to the internal Clock of the AD9957, but at least I'll be able to talk to the chip and see if it does anything at all
- C31_HFS: Sits across the cutout for the shield of the ADF4355 Loop-Filter
- ADF4355 Loop-Filter:
- Silkscreen hard to read (Needs to be rearranged)
- Power-Traces are inside the shield-area (need to be moved outside or to the 3rd (Power) Layer)
- Tantal Capacitors: Indicator for positive side hard to see in densely populated areas
- Power Idication-LEDs: Only one color and the large Vias are placed BETWEEN Resistor and LED, so no easy to access test-points to measure voltages from PSU-Section
Not so much a problem, but some things I realized during soldering:
- Assembly: It can get kinda hard to head up GND-Pads and especially through hole contacts. Thermal relief-connects, at least to the large ground plane, might be a good idea.
- RF Power-Supply: It looks a bit too chaotic for my taste.