ncv8881 ON Semiconductor, ncv8881 Datasheet - Page 20

• Manufacturer Part Number: ncv8881
• Description: Ncv8881 1.5a Automotive Buck Regulator With Watchdog
• Manufacturer: ON Semiconductor

ENABLE (EN PIN)
maintain a standby mode which keeps the switching
regulator, Watchdog Circuit, and LDO outputs off, and
minimizes supply current. In this state the RESB output is
low. A high logic level at the EN input activates all functions.
Upon EN exceeding V
established, followed by soft−start of the switching
OUTPUT
OUTPUT
ENABLE
ENABLE
After VIN rises above V
SMPS
SMPS
8P5
5P0
8P5
5P0
VIN
VIN
8P5 Regulation Monitor Threshold
5P0 Regulation Monitor Threshold
8P5 Regulation Monitor Threshold
5P0 Regulation Monitor Threshold
0
0
1
1
ENSTHH
STRT
2
2
Figure 43. Enable High Time Long Enough to be Latched
, 5P0 and 8P5 voltages are
, EN below V
Figure 42. Enable High Time Insufficient to be Latched
3
3
ENSTHL
4
4
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will
5
5
20
regulator. Once either the 5P0 or 8P5 LDO reaches
regulation, EN dropping below V
the SS Timer expires. Thereafter, if the SMPS output voltage
is out of regulation, or WDI pulse period exceeds the
Watchdog Delay time t
part in standby mode.
6
6
7
7
8
8
WD
, EN below V
9
9
ENSTHL
10
10
has no effect until
ENSTHL
11
11
puts the
12
12