Atmel ATA6264 - Manual (Page 15)

15
4929B–AUTO–01/07
ATA6264 [Preliminary]
Depending on the initial programming of the ATA6264, the start-up procedure takes place in dif-
ferent phases.
5.3.1 Start-up Procedure if V
VCORE
is Programmed to Be 5V or 2.5V
Phase1: After switching on the ignition key, K15 voltage will apply at pin K15. If, in addition, the
voltage at pin K30 is larger than 3.85V to 5V, the EVZ regulator will be enabled. The signal
K15GOOD can be replaced by the serial interface command KEYLATCH which can be set via
the serial interface.
Phase2: If V
EVZ
is larger than 7.5V to 9V the VSAT regulator starts operating and the VCORE
regulator will be enabled.
Phase3: After V
VSAT
has reached 6.77V to 7.2V, the VPERI regulator starts working. The
VCORE regulator starts operating depending on the charge pump voltage.
5.3.2 The Power-down Procedure Takes Place in Different Phases
Phase1: If the ignition key is switched off, K15 voltage will vanish at pin K15. If the serial inter-
face command KEYLATCH is not set, the EVZ regulator stops working. The external charge
pump is still working because EVZ is above VSAT and the VSAT regulator is not in Perma-
nent-on mode. The charge-pump voltage still supplies the VSAT regulator and the VCORE
regulator. Because the EVZ regulator stops working, VCORE will be switched to EVZ.
Phase2: The EVZ capacitor will be discharged, and as soon as the voltage at pin VSAT drops to
low, the VSAT regulator will go into Permanent-on mode. If VSAT reaches Permanent-on mode,
the external charge pump stops working and the VSAT voltage falls analog to the EVZ voltage. If
the voltage at VSAT is below 6.27V to 7V, the VPERI regulator will be switched off. Depending
on the charge-pump voltage, the VCORE regulator stops working.
Phase3: When the voltage at the EVZ capacitor gets to be lower than 5.5V to 6.2V, VSAT is
switched off.