ST7580

Power management

Doc ID 022644 Rev 1

19/33

6

Power management

Figure 9

shows the power supply structure for the ST7580. The ST7580 operates from two

external supply voltages:

●

VCC (8 to 18 V) for the power amplifier and the analog section

●

VDDIO (3.3 or 5 V) for interface lines and digital blocks.

Two internal linear regulators provide the remaining required voltages:

●

5 V analog front end supply: generated from the VCC voltage and connected to the

VCCA pin

●

1.8 V digital core supply: generated from the VDDIO voltage and connected to

VDD_REG_1V8 (direct regulator output) and VDD pins.

The VDD_PLL pin, supplying the internal clock PLL, must be externally connected to VDD

through a ferrite bead for noise filtering purposes.

All supply voltages must be properly filtered to their respective ground, using external

capacitors close to each supply pin, in accordance with the supply scheme depicted in

Figure 9

.

Note that the internal regulators connected to VDD_REG_1V8 and to VCCA are not

designed to supply external circuitry; their outputs are externally accessible for filtering

purposes only.

External connections between all VDD pins are not required.