lp8720tlx National Semiconductor Corporation, lp8720tlx Datasheet - Page 5

• Manufacturer Part Number: lp8720tlx
• Description: One Step-down Dc/dc And Five Linear Regulators With I2c Compatible Interface
• Manufacturer: National Semiconductor Corporation

POWER-ON AND POWER-OFF SEQUENCES
t
t
Note 1 START UP and SHUT DOWN sequences are defined by registers. Sequences given here are valid if there the registers
Note 2 The timing showed here define time points when LDO’s and BUCK are enabled/disabled. Enabling /disabling process
Note 3 LDO5 and BUCK are disabled. If LDO5 and/or BUCK are enabled via Serial Interface and startup sequence is not changed
Note 4 At this time point registers 0x09 and 0x0C are reset to POR default values.
Note 5 At this time point registers 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 and 0x08 are reset to POR default values.
BON
S
150 µs – Reference and bias turn ON. Min 100 µs max 200 µs.
25 µs – time step. Time step accuracy is defined by OSC frequency accuracy.
are not rewritten via Serial Interface.
duration depends on loading conditions. Buck startup duration is 140 µs for no load. LDO startup duration is no more than
35 µs. For details please see LDO’s and BUCK electrical specifications.
via Serial interface, then LDO5 and BUCK are disabled with no delay from falling edge on EN-pin.
Start Up Sequence if DEFSEL=VBATT or DEFSEL=Hi-Z
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