3.11.2.4 VS_PA Supply Voltage Regulator

ATA8510/15 provides a 3V and 5V Application mode because the power amplifier cannot operate directly from a 5V battery supply voltage. The SUPCR.PVEN register bit configures the mode of operation.

• Use the 3V Application mode for a battery supply voltage ranging from 1.9-3.6V. In this mode, connect the battery directly to the VS pin and the VS_PA pin.

• If the battery exceeds the maximum voltage of 3.6V, use the 5V Application mode. Disconnect the VS_PA pin from the battery supply voltage.

• The RF output power is strongly dependent on the voltage at the VS_PA pin. To extend the duration of constant RF output power, select a special 2.2V mode by setting the SUPCA1.PV22 register bit.

• Disconnect the VS_PA pin from the battery supply voltage for the 5V Application mode. In this mode, the internal VS_PA voltage regulator provides the supply voltage for the power amplifier. An external 68-nF capacitor guarantees the stability of the internal VS_PA voltage regulator. For this capacitor, do not use the values other than 68 nF.