SLOS758G December 2011 – March 2020 TRF7963A
The TRF7963A positive supply input VIN (pin 2) sources three internal regulators with output voltages VDD_RF, VDD_A, and VDD_X. All regulators require external bypass capacitors for supply noise filtering and must be connected as indicated in reference schematics. These regulators provide a high power supply reject ratio (PSRR) as required for RFID reader systems. All regulators are supplied by VIN (pin 2).
The regulators are not independent and have common control bits in register 0x0B for output voltage setting. The regulators can be configured to operate in either automatic or manual mode (register 0x0B, bit 7). The automatic regulator setting mode ensures an optimal compromise between PSRR and the highest possible supply voltage for RF output (to ensure maximum RF power output). The manual mode lets the user manually configure the regulator settings.