WTS701EMSLASHT datasheet(14/77 Pages) WINBOND

14 / 77 page

WTS701

- 14 -

7.2.2 Power Down Mode

Upon application of power, the WTS701 will enter the RESET state and then be in a POWER DOWN

state. In the POWER DOWN mode, only Class0 SPI commands are valid. (See subsection 7.3.1). The

Power Down status of the device can be determined with a RDST (Read Status) command, specified

by the RDY bit in STATUS BYTE 0.

Issuing the PWDN (Power Down) command to the WTS701 processor will return the processor to the

POWER DOWN mode. In POWER DOWN mode the external crystal oscillator is shut off and the

processor is deactivated. POWER DOWN mode is exited by issuing a PWUP (Power Up) command

to the WTS701. The PWUP command should be preceded by a SCLC (Set Clock) command to

ensure correct clock configuration.

7.2.3 Power and Grounding

The WTS701 can operate over 2.7V to 3.3V supply voltage range. The power supply and ground pins

(VCCA, VCCD, VSSA, VSSD) should be carefully bypassed as close to the chip as possible to ensure high

quality audio. In addition, ATTCAP pin should have a 4.7 µF capacitor connected to ground. This pin

must NOT be left floating. The pins that are marked as NC (Not Connected), MUST be left floating.

VCCA, VCCD (Voltage Inputs)

To minimize noise, the analog and digital circuits in the WTS701 device use separate power busses.

These +3.0 V busses lead to separate pins. For optimal noise immunity, tie the VCCD pins together as

close as possible and decouple both supplies as near to the package as possible.

VSSA, VSSD (Ground Inputs)

The WTS701 series utilizes separate analog and digital ground busses. The analog ground (VSSA)

pins should be tied together as close to the package as possible and connected through a low-

impedance path to power supply ground. The digital ground (VSSD) pin should be connected through a

separate low-impedance path to power supply ground. These ground paths should be large enough to

ensure that the impedance between the VSSA pins and the VSSD pin is less than 3Ω. The backside of

the die is connected to VSSD through the substrate resistance.

NC (Not Connect)

These pins MUST not be connected to the board at any time. Connection of these pins to any signal,

ground or VCC may result in incorrect device behavior or cause damage to the device.

WTS701EM/T 데이터시트(PDF) 14 Page - Winbond