ncp382 ON Semiconductor, ncp382 Datasheet - Page 9

• Manufacturer Part Number: ncp382
• Description: Ncp382 Fixed Current-limiting Power-distribution Switches
• Manufacturer: ON Semiconductor

Enable Input
TTL compatible) or connected to the GND or VIN. A logic
low on ENX or high on ENX turns−on the device. A logic
high on ENX or low on ENX turns off device and reduces
the current consumption down to I
Blocking Control
power MOS. When the part is off, the body diode limits the
Power Dissipation
different contributing factors such as board layout, ambient
temperature, device environment, etc... Yet, the main
contributor in term of junction temperature is the power
dissipation of the power MOSFET. Assuming this, the
power dissipation and the junction temperature in normal
mode can be calculated with the following equations:
P
R
I
T
R
T
OUTx
D
A
J
DS(on)
qJA
Enable pin must be driven by a logic signal (CMOS or
The blocking control circuitry switches the bulk of the
The junction temperature of the device depends on
P
D
+ R
DS(on)
T
= Power dissipation (W)
= Power MOSFET on resistance (W)
= Output current in channel X (A)
= Junction temperature (°C)
= Package thermal resistance (°C/W)
= Ambient temperature (°C)
J
+ P
D
I
OUT1
R
qJA
INOFF
2
) T
) I
A
.
OUT2
APPLICATION INFORMATION
2
(eq. 2)
(eq. 3)
http://onsemi.com
9
leakage current I
of the body diode is connected to IN pin and cathode is
connected to OUTX pin. In operating condition, anode of
the body diode is connected to OUTX pin and cathode is
connected to IN pin preventing the discharge of the power
supply.
taking into account the drop V
the following relation:
P
V
R
I
PCB Recommendations
and the PCB design rules must be respected to properly
evacuate the heat out of the silicon. The DFN8 PAD1 must
be connected to ground plane to increase the heat transfer if
necessary. Of course, in any case, this pad must not connect
to any other potential. By increasing PCB area, the R
the package can be decreased, allowing higher current.
OCP
D
P
LOADX
IN
Power dissipation in regulation mode can be calculated by
The NCP382 integrates two PMOS FET rated up to 1.5 A,
D
+
V
I
IN
OCP
* R
REV
LOAD1
= Power dissipation (W)
= Input Voltage (V)
= Load Resistance on channel X (W)
= Output regulated current (A)
from OUTX to IN. In this mode, anode
I
OCP
IN
) V
−V
OUTX
IN
* R
link to the load by
LOAD2
I
OCP
(eq. 4)
qJA
of