Introductory Tests

Power/LDO Tests

This test’s purpose is to confirm that the LDO provides sufficient voltage and current to the frontend IC.

1. Connect the board to 5V using a power supply. Note the current draw at this point.
2. Probe the appropriate vias and pins to ensure the chip is being powered with 4.2V (decoupling caps, the output of LDO, VCC pin on IC, etc.
3. Pull the TR and EN pin HIGH to enable transmit mode. The current draw should increase. Also, check again that the LDO is still stepping down to 4.2V.
4. Now, try and find the dropout voltage point of the LDO. This is when the output voltage of the LDO drops significantly.
   1. The datasheet says 600mA, so we expect the drop-off to occur at roughly 4.8V.
5. If it does not step down properly, try to increase the supply voltage to see if the dropoff voltage is the issue.

Antenna - TX (Simulated Transmit)

This test’s purpose is to simulate the transmit end of the RFFE board.

1. Connect the signal generator to the TX SMA connector on the board
2. Connect the Spectrum analyzer to the ANT SMA connector on the board
3. Configure the signal generator to output a 16dBm waveform running at ~433MHZ
4. Use a power supply to supply power to the RFFE Board, and pull the TR and EN pins high.
5. Quickly check that adequate power is being supplied to the board
6. Enable the waveform output and observe the output wave on the Spectrum Analyzer. We expect roughly 31dBm (1W) out of the antenna connector.

Antenna - RX (Simulated Receive)

This test’s purpose is to simulate the receive end of the RFFE board.

1. Connect the signal generator to the ANT SMA connector on the board
2. Connect the Spectrum analyzer to the RX SMA connector on the board