TC-L-04 — SX1276 supply rail voltages — VCC_RF and VCC

1. Probe each SX1276 supply pin (VCC_RF — RF amp supply; VCC — digital supply) individually against GND with a DMM. All pins must read 3.3 V ± 0.1 V.
2. Check each rail for ripple with a scope (10× probe). AC component must be ≤ 50 mVpp. Any rail exceeding 50 mVpp ripple is a fail.
3. If a separate DC-DC or LDO supplies the RF rail: confirm EN is driven HIGH and output is in regulation before the SX1276 reset is released.

Pass: all supply pins present at 3.3 V ± 0.1 V, ripple ≤ 50 mVpp on all rails.