SC1544 Ver la hoja de datos (PDF) - Semtech Corporation
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componentes Descripción
Fabricante
SC1544 Datasheet PDF : 15 Pages
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POWER MANAGEMENT
Applications Information (Cont.)
.ault Protection Hints (Cont.)
that the OCP times out then the outputs will latch off.
Then if the AC power returns after the OCP latches off,
but before the 5VSB supply drops below UVLO, then the
device will not start up again until EN or 5VSB is cycled.
One way to avoid this happening is to force the device
into S3 if PWR_OK goes low but S3 and S5 remain high
using the circuit shown below. This will supply the
outputs from 5VSB which will either cause 5VSB to drop
below UVLO and reset the part when the AC power comes
back up, or it may prevent OCP occuring at all. Either way
correct functionality will be guaranteed once AC power
returns.
PWR_OK
/SLP_S3
D1
1N4148
R1 4.7k
U1
1
G5
2
2.5VDM
3
G6
4
G7
5
AGP
6
TYPEDET
7
PWR_OK
8
EN
9
/S3
10
/S5
11
USB
12
PCI
SC1544-2.5
24
G8
23
1.8V
22
G4
21
3.3VD
20
GND
19
G2/3
18
G1
17
5VD
16
5VSB
15
FC
14
+CAP
13
-CAP
Incorrect Signals .rom Silver Box: Some silver boxes
have been found that produce incorrect voltages on the
PWR_OK line, producing dangerous negative voltage
spikes up to -1V or greater. Such spikes exceed the
absolute maximum ratings for this device and can cause
the device to malfunction. If a supply produces such
spikes they can be clamped to GND using a small schottky
diode as shown below, completely removing any threat.
PWR_OK
D1
U1
1
G5
2
2.5VDM
3
G6
4
G7
5
AGP
6
TYPEDET
7
PWR_OK
8
EN
9
/S3
10
/S5
11
USB
12
PCI
SC1544-2.5
24
G8
23
1.8V
22
G4
21
3.3VD
20
GND
19
G2/3
18
G1
17
5VD
16
5VSB
15
FC
14
+CAP
13
-CAP
2002 Semtech Corp.
14
SC1544
PRELIMINARY
www.semtech.com
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