LTC4253AIUF-ADJ Linear Technology, LTC4253AIUF-ADJ Datasheet - Page 25

• Manufacturer Part Number: LTC4253AIUF-ADJ
• Description: IC,Power Control/Management,CMOS,LLCC,20PIN,PLASTIC
• Manufacturer: Linear Technology

Specifications of LTC4253AIUF-ADJ

• Family Name: LTC4253A-ADJ
• Package Type: QFN EP
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Product Depth (mm): 4mm
• Product Length (mm): 4mm
• Mounting: Surface Mount
• Pin Count: 20
• Lead Free Status / Rohs Status: Not Compliant

APPLICATIO S I FOR ATIO
V
V
timing behavior as the UV pin timing except it looks at V
< (V
undervoltage lockout condition, both UV and OV com-
parators are held off. When V
the UV and OV comparators are enabled.
IN
IN
undervoltage lockout comparator, UVLO has a similar
Undervoltage Lockout Timing
LKO
SQTIMER
– V
PWRGD1
PWRGD2
PWRGD3
SENSE
TIMER
DRAIN
GATE
LKH
UVL
EN2
EN3
UV
SS
) to shut down and V
UVL DROPS BELOW V
1
U
V
V
UVLO
GATEL
U
UV CLEARS V
2
Figure 10. Undervoltage Timing (All Waveforms are Referenced to V
IN
V
UVHI
exits undervotlage lockout,
UVLO
UVHI
IN
. GATE, SS AND TIMER ARE PULLED DOWN, PWRGD RELEASES
W
> V
5µA
INITIAL TIMING
, CHECK OV CONDITION, RESET < 0.8V, GATE < V
LKO
50µA
to start. In an
20 • (V
20 • (V
U
V
ACL
TMRH
CB
20 • V
V
+ V
+ V
TMRL
OS
OS
IN
OS
)
)
50µA
3 4 56
TIMER CLEARS V
200µA + 8 • I
Overvoltage Timing
During normal operation, if the OV pin exceeds V
shown at time point 1 of Figure 11, the TIMER and PWRGD
status are unaffected; SS and GATE pull down; load
disconnects. At time point 2, OVL recovers and drops
below the V
overvoltage glitch is long enough to deplete the load
capacitor, time points 4 through 7 may occur.
START-UP
GATE
7
50µA
8 9 A B
DRN
GATEL
TMRL
V
SQTMRH
5µA
, SENSE < V
OVLO
, CHECK GATE < V
V
V
V
V
V
IN
ACL
CB
DRNCL
DRNL
– V
5µA
GATEH
threshold; GATE start-up begins. If the
C
CB
5µA
, SS < 20 • V
GATEL
D
LTC4253A-ADJ
EE
, SENSE < V
OS
)
AND TIMER < V
E
5µA
V
CB
SQTMRL
AND SS < 20 • V
4253 F10
TMRL
OS
25
OVHI
4253a-adjf
as