Hi
I use LMP92066 in my design. Now i have some question. Please help deal with it. Thanks!
1. I can use it for LDMOS without EEPROM. Now i want to use it to driver GaN. It can't work well. Schematic diagram as below.
2.Disconnect the amplifier load at the back end of PIN13 and PIN11, and pull PIN2 and PIN3 to high level.
3. When the initial PCBA has not been burned, the state after power on: VCC_3V3 measured as 3.3V, VCC_RF_5V measured as 5V, and VCC_RF_-5V measured as -5V;R6 and R159 are -5V;C164 and C165 are 0.
4. Write the default values of DAC0 and DAC1 in registers as 0x1000 (13Bits).
5. After the success of the burning software, it is found that VCC_RF_-5V has been short-circuit.
6. Remove the LMP92066, measure the LDO (load capacity is about 100mA) with each pin open to ground and supply power to the LMP92066, and the -5V output is normal.
7. After checking the manual, it is found that DAC output is 12Bits. Modify the default values of software DAC0 and DAC1 and write them as 0xF00.
8. The test is normal after multiple power ups and downs.
9. After a period of time, when testing other cases, it was found that the output of -5V was abnormal again, and the supply voltage was only -3.2V.After removing the LMP92066 and measuring the LDO, the output of -5V is normal.
10. Power on time of VCC_3V3, VCC_RF_5V and VCC_RF_-5V is shown below:
