EN

Buck 1

0 1 2 3

Buck 2

START UP sequence

Timing Code

SHUT DOWN sequence

is in reverse order of START UP sequence

Timing Code

Buck 1

0

1

2

3

Buck 2

LDO1

LDO1

LDO3

LDO3

START UP

SHUT DOWN

IDLE

Note 4

LDO4

LDO4

LDO5

LDO5

LILO 2

LILO 2

LILO 1

LILO 1

4 5 6

6 5 4

LDO2

LDO2

EN

Note 3

Note 3

Note 5

Note 3

Note 3

STANDBY

STANDBY

LP8725

SNVS618G – DECEMBER 2009 – REVISED MAY 2013

www.ti.com

Figure 10. LP8725-B Startup and Shutdown Sequence if CONFIG=GND,

All timing is typical.

Note 1 STARTUP and SHUT DOWN sequences are defined by registers. Sequences given here are valid if there the

registers are not rewritten via Serial Interface.

Note 2 The timing showed here define time points when LDOs and BUCK are enabled/disabled. Enabling /disabling

process duration depends on voltages and loading conditions. Buck startup duration is typically 170 µs. LDO startup

duration is typically 35 µs. For details please see LDOs and BUCK Electrical Specifications.

Note 3 LDO2, 4, 5 and LILO1 are disabled. If they are enabled via Serial Interface and the startup sequence is not

changed, then they will be disabled, with no delay, from falling edge of EN-pin.

Note 4 At this time point registers are reset to POR default values.

Note 5 LDO3 is enabled by LDO3_EN (or via serial interface). If this input is high when PWR_ON goes high then this

14

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