NCP4640
http://onsemi.com
15
APPLICATION INFORMATION
A typical application circuit for NCP4640 series is shown
in Figure 42.
VIN VOUT
CE
GND
C1 C2
100 n 100n
VIN VOUT
NCP4640x
Figure 42. Typical Application Schematic
Input Decoupling Capacitor (C1)
The device is stable without any input capacitance, but if
input line is long and has high impedance or if more stable
operation is needed, input capacitor C1 should be connected
as close as possible to the IC. Recommended range of input
capacitor value is 100 nF to 10 mF.
Output Decoupling Capacitor (C2)
The NCP4641 can work stable without output capacitor,
but if faster response and higher stability reserve is needed,
output capacitor should be connected as close as possible to
the device. Recommended range of output capacitance is
100 nF to 10 mF. Larger values of output capacitance and
lower ESR improves dynamic parameters.
Enable Operation
The enable pin CE may be used for turning the regulator
on and off. The device is activated when high level is
connected to CE pin. Do not keep CE pin not connected or
between VCEH and VCEL voltage levels. Otherwise output
voltage would be unstable or indefinite and unexpected
would flow internally.
Thermal
As a power across the IC increase, it might become
necessary to provide some thermal relief. The maximum
power dissipation supported by the device is dependent
upon board design and layout. Mounting pad configuration
on the PCB, the board material, and also the ambient
temperature affect the rate of temperature increase for the
part. When the device has good thermal conductivity
through the PCB the junction temperature will be relatively
low in high power dissipation applications.
The IC includes internal thermal shutdown circuit that
stops operation of regulator, if junction temperature is
higher than 150°C. After that, when junction temperature
decreases below 125°C, the operation of voltage regulator
would restart. While high power dissipation condition is, the
regulator starts and stops repeatedly and protects itself
against overheating.
PCB layout
Pins number 2 and 4 of SOT89−5 package and pins
number 2, 4 and 5 of SOIC6−TL must be wired to the GND
plane while it is mounted on board. Make VIN and GND
lines sufficient. If their impedance is high, noise pickup or
unstable operation may result. Connect capacitors C1 and
C2 as close as possible to the IC, and make wiring as short
as possible.
ORDERING INFORMATION
Device
Nominal Output
Voltage
Description Marking Package Shipping
†
NCP4640H020T1G 2.0 V Enable High N020 SOT89−5
(Pb−Free)
1000 / Tape & Reel
NCP4640H030T1G 3.0 V Enable High N030 SOT89−5
(Pb−Free)
1000 / Tape & Reel
NCP4640H033T1G 3.3 V Enable High N033 SOT89−5
(Pb−Free)
1000 / Tape & Reel
NCP4640H080T1G 8.0 V Enable High N080 SOT89−5
(Pb−Free)
1000 / Tape & Reel
NCP4640H120T1G 12.0 V Enable High N120 SOT89−5
(Pb−Free)
1000 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
*To order other package and voltage variants, please contact your ON Semiconductor sales representative.
