|
|
PDF SC339 Data sheet ( Hoja de datos )
| Número de pieza | SC339 | |
| Descripción | Ultra Low Output Voltage Linear FET Controller | |
| Fabricantes | Semtech | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de SC339 (archivo pdf) en la parte inferior de esta página. Total 15 Páginas | ||
|
No Preview Available !
POWER MANAGEMENT
Description
The SC339 is an ultra-low output voltage, linear power
supply controller designed to simplify power manage-
ment for notebook PCs. It is part of Semtech’s Smart
LDOTM family of products. The SC339 has a user
adjustable output that can be set anywhere between 0.5V
and 3.3V using two external resistors.
SC339 features include tight output voltage regulation (±
1% over 0°C to +85°C), enable control, open drain power
good signal, under-voltage protection and soft-start. The
wwenwa.DbaletapShineeatl4loUw.csotmhe part to enter a very low power standby
mode. Pulling it high enables the output. The power good
pin is an open drain and asserts low when the voltage at
the adjust pin is below 88% (typ) of nominal. If the voltage
at the adjust pin is below 50% (typ) of nominal, the under-
voltage protection circuitry will shut down the output. The
SC339 is available in a tiny SOT-23 6-pin surface mount
package.
Typical Application Circuit
1.2V +/-5% IN
SC339
Ultra Low Output Voltage
Linear FET Controller
Features
± 1% Voltage Accuracy Over-Temperature
Low Shutdown Current
Runs Off 5V Supply
Ultra-Fast Transient Response
Enable Control for the Output
Power Good Monitoring and Signaling for the Output
Gate Drive from Input Supply Enables Use of
N-Channel MOSFET
User Selectable Dropout Voltage
Under-Voltage Protection for the Output
SOT-23 6-pin Surface Mount Package
Compatible with Ceramic Capacitors
Low Ripple Output
Internal 1ms soft-start requires no external compo-
nents
Fully WEEE and RoHS compliant
Applications
Notebook PCs
Desktop Computers
Battery Powered Devices
Portable Instruments
IRF7311
C1 or similar
5V IN
Sept 11, 2006
1.05V
Enable
IN DRV
GND SC339 ADJ
EN PGD
1.05V
Power Good
R3 (1)
C4
Notes:
(1) Optional Components to use with ceramic output
capacitors (C2)
C3 (1)
1
Vout = (1+R1/R2)*0.5
1.05V @ 3A
C2
R1
R2
www.semtech.com
1 page  
POWER MANAGEMENT
Block Diagram
EN
DRV
www.DataSheet4U.com
Shutdown
Control
PGD
Under
Voltage
Control
SC339
IN
0.5V
Bandgap
Reference
Vref
( 0.5V)
+ Vref
-
Error
Amplifier
+ 0.5 VBG
-
Undervoltage
Comparator
+
0.88 VBG
(0.95 VBG
At start-up)
-
Power Good
Comparator
ADJ
GND
© 2006 Semtech Corp.
5
www.semtech.com
5 Page 
SC339
POWER MANAGEMENT
Applications Information (Cont.)
Now,
C3 = ½ • • R3 • 3kHz = 530nF
We choose C3 = 470nF as the standard value.
Layout Guidelines
The advantages of using the SC339 to drive external
MOSFETs are:
Soft-Start Behavior
At start-up, VOUT first ramps linearly from ground at the rate of
~0.5V/ms (+/- 25%) for about 800us. The linear ramping is
followed by a phase of smooth settling for about 700us at the
end of which the output has fully settled (to better than 1%).
www.DataSheet4U.com
The total start-up time of about 1.5ms is kept within 1ms
- 2ms window, and this is regardless of the loading and
of the external components connected to the device.
a) that the bandgap reference and control circuitry are in a
die that does not contain high power dissipating devices
and,
b) that the device itself does not need to be located right
next to the power devices. Thus very accurate output
voltages can be obtained since changes due to heating
effects will be minimal.
The 0.1μF bypass capacitor should be located close to the
supply (IN) and GND pins, and connected directly to the
ground plane.
The feedback resistors should be located at the device,
with the sense line from the output routed from the load
(or top end of the droop resistor if passive droop is being
used) directly to the feedback chain. If passive droop is
being used, the droop resistor should be located next to the
load to avoid adding additional unplanned droop. Sense
and drive lines should be routed away from noisy traces
or components.
SC339 Start-Up Response
For very low input to output voltage differentials, the
input to output/load path should be as wide and short
as possible. Where greater headroom is available, wide
traces may suffice.
Power dissipation within the device is practically
negligible, thus requiring no special consideration dur-
ing layout. The MOSFET pass devices should be laid out
according to the manufacturer’s guidelines for the power
being dissipated within them.
© 2006 Semtech Corp.
11
www.semtech.com
11 Page | ||
| Páginas | Total 15 Páginas | |
| PDF Descargar | [ Datasheet SC339.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| SC33020H | 2A Load Switch | Semtech |
| SC3306 | (SC3306 / SC3308) 20-OUTPUT LVTTL CLOCK DRIVERS |  AMCC |
| SC33063A | (SC33063A / SC34063A) Step-Up/Down/ Inverting Switching Regulators |  ON Semiconductor |
| SC3308 | (SC3306 / SC3308) 20-OUTPUT LVTTL CLOCK DRIVERS | AMCC |
| 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 |