Datasheet

LTC4253B
25
4253bf
applicaTions inForMaTion
50µA
V
SQTMRL
UV CLEARS V
UVHI
, CHECK OV CONDITION, RESET < 0.8V, GATE < V
GATEL
, SENSE < V
CB
, SS < 20 • V
OS
AND TIMER < V
TMRL
TIMER CLEARS V
TMRL
, CHECK GATE < V
GATEL
, SENSE < V
CB
AND SS < 20 • V
OS
UV
TIMER
GATE
SENSE
SS
DRAIN
PWRGD1
PWRGD2
PWRGD3
SQTIMER
EN2
EN3
1 2 3 4 56 7 8 9 A B C D
4253b F09
INITIAL TIMING
GATE
START-UP
20 • (V
ACL
+ V
OS
)
20 • (V
CB
+ V
OS
)
20 • V
OS
5µA
5µA
UV DROPS BELOW V
UVLO
. GATE, SS AND TIMER ARE PULLED DOWN, PWRGD RELEASES
V
UVLO
V
GATEL
V
UVHI
V
ACL
V
SQTMRH
V
SQTMRL
V
CB
5µA
5µA
50µA
V
SQTMRH
V
DRNCL
V
DRNL
V
IN
– V
GATEH
50µA
200µA + 8 • I
DRN
V
TMRH
V
TMRL
5µA
Figure 9. Undervoltage Timing (All Waveforms Are Referenced to V
EE
)