|
|
PDF LSP5503 Data sheet ( Hoja de datos )
| Número de pieza | LSP5503 | |
| Descripción | 3A Synchronous Step Down DC/DC Converter | |
| Fabricantes | Liteon Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LSP5503 (archivo pdf) en la parte inferior de esta página. Total 10 Páginas | ||
|
No Preview Available !
LSP5503
3A Synchronous Step Down DC/DC Converter
FEATURES
z 3A Output Current
z Wide 4.5V to 27V Operating Input Range
z Integrated 100m Power MOSFET Switches
z Output Adjustable from 0.925V to 24V
z Up to 96% Efficiency
z Programmable Soft-Start
z Stable with Low ESR Ceramic Output Capacitors
z Fixed 400KHz Frequency
z Cycle-by-Cycle Over Current Protection
z Input Under Voltage Lockout
z SOP8L-EP Package
GENERAL DESCRIPTION
The LSP5503 is a monolithic synchronous buck
regulator. The device integrates 100mΩ MOSFETS
that provide 3A continuous load cur-rent over a wide
operating input voltage of 4.5V to 27V. Current mode
control provides fast transient response and
cycle-by-cycle cur-rent limit.
An adjustable soft-start prevents inrush current at turn
on. In shutdown mode, the supply cur-rent drops
below 1µA.
This device, available in an SOP8L-EP package,
provides a very compact system solution with minimal
reliance on external components.
TYPICAL APPLICATION
z Distributed Power Systems
z Networking Systems
z FPGA, DSP, ASIC Power Supplies
z Green Electronics/ Appliances
z Notebook Computers
PIN ASSIGNMENT
http://www.DataSheet4U.net/
PIN DESCRIPTION
Name
BS
No.
1
IN 2
SW 3
G4
FB 5
COMP
6
EN 7
SS 8
LSP5503 Rev. 1.3
(Top View)
Description
Bootstrap. This pin acts as the positive rail for the high-side switch’s gate driver.
Connect a 0.1uF capacitor between BS and SW.
Input Supply. Bypass this pin to G with a low ESR capacitor. See Input Capacitor
in the Application Information section.
Switch Output. Connect this pin to the switching end of the inductor.
Ground.
Feedback Input. The voltage at this pin is regulated to 0.925V. Connect to the
resistor divider between output and ground to set output voltage.
Compensation Pin. See Stability Compensation in the Application Information
section.
Enable Input. When higher than 2.5V, this pin turns the IC on. When lower than
1.3V, this pin turns the IC off. Output voltage is discharged when the IC is off. This
pin should not be left open.
Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from
SS to GND to set the soft-start period. A 0.1µF capacitor sets the soft-start period
to 15ms. To disable the soft-start feature, leave SS unconnected.
1 of 10
www.liteon-semi.com
2009/09
datasheet pdf - http://www.DataSheet4U.net/
1 page  
LSP5503
3A Synchronous Step Down DC/DC Converter
Output Capacitor
The output capacitor also needs to have low ESR to keep low output voltage ripple. The output ripple voltage is:
VRIPPLE = IOUTMAX K RIPPLE RESR
+
28
VIN
• f SW 2 LCOUT
(3)
where IOUTMAX is the maximum output current, KRIPPLE is the ripple factor, RESR is the ESR of the output capacitor, fSW
is the switching frequency, L is the inductor value, and COUT is the output capacitance. In the case of ceramic output
capacitors, RESR is very small and does not contribute to the ripple. Therefore, a lower capacitance value can be
used for ceramic capacitors. In the case of tantalum or electrolytic capacitors, the ripple is dominated by RESR
multiplied by the ripple current. In that case, the output capacitor is chosen to have sufficiently low ESR.
For ceramic output capacitors, typically choose a capacitance of about 22µF. For tantalum or electrolytic capacitors,
choose a capacitor with less than 50mΩ ESR.
Optional Schottky Diode
During the transition between high-side switch and low-side switch, the body diode of the low side power MOSFET
conducts the inductor current. The forward voltage of this body diode is high. An optional Schottky diode may be
paralleled between the SW pin and GND pin to improve overall efficiency. Table 2 lists example Schottky diodes and
their Manufacturers.
Stability Compensation
http://www.DataSheet4U.net/
CCOMP2 is needed only for high ESR output capacitor
Figure 2. Stability Compensation
The feedback loop of the IC is stabilized by the components at the COMP pin, as shown in Figure 2. The DC loop
gain of the system is determined by the following equation:
(4)
The dominant pole P1 is due to CCOMP:
fP1
=
G EA
2 πAVEA C C OM P
(5)
The second pole P2 is the output pole:
fP2
=
IOUT
2πVOUT COUT
(6)
The first zero Z1 is due to RCOMP and CCOMP:
fZ1
=
1
2πRCOMP CCOMP
(7)
And finally, the third pole is due to RCOMP and CCOMP2 (if CCOMP2 is used):
fP3
1
= 2πRCOMP CCOMP2
(8)
LSP5503 Rev. 1.3
5 of 10
www.liteon-semi.com
2009/09
datasheet pdf - http://www.DataSheet4U.net/
5 Page | ||
| Páginas | Total 10 Páginas | |
| PDF Descargar | [ Datasheet LSP5503.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LSP5502 | 2A Synchronous Step Down DC/DC Converter |  Lite-On |
| LSP5503 | 3A Synchronous Step Down DC/DC Converter | Liteon Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |