|
|
PDF SC2612C Data sheet ( Hoja de datos )
| Número de pieza | SC2612C | |
| Descripción | 600kHz/200kHz Step-Down DC/DC Converter | |
| Fabricantes | Semtech | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de SC2612C (archivo pdf) en la parte inferior de esta página. Total 12 Páginas | ||
|
No Preview Available !
POWER MANAGEMENT
Description
The SC2612 is a voltage mode switcher designed for low
cost, “point of use” voltage conversion. SC2612 is avail-
able with fixed switching frequencies of 600kHz
(SC2612A) and 200kHz (SC2612C).
The SC2612 has soft start and enable functions and is
short circuit protected. The output of the switcher may
be set anywhere between 0.8V and 75% of Vin. Short
circuit protection is disabled during start-up to allow the
output capacitors time to fully charge.
SC2612A/C
600kHz/200kHz
Step-Down DCw/wDw.DCataCShoeent4Uv.ceomrter
Features
u Operating frequency of 600kHz or 200kHz
u Input supply of 3V to 8V
u 0.5A Drive current for up to 10A output
u Output voltages down to 0.8V
u Overcurrent protection and soft start
u MSOP-8 package
Applications
u Graphics IC Power supplies
u Embedded, low cost, high efficiency converters
Typical Application Circuit
3.3V IN
R1
C5
C7
C9
R9
12V IN
C10 C1
C2
U2
4 VCC BST 8
1 COMP DH 7
2 SS/EN DL 6
5 GND FB 3
SC2612
R2
R3
Q2
L1
Q3
C3
1.5V OUT
R6
R10
August 18, 2004
1 www.semtech.com
1 page  
SC2612A/C
POWER MANAGEMENT
Theory of Operation
Component Selection
www.DataSheet4U.com
The SC2612 is a step down DC/DC controller designed
for minimum cost and size without sacrificing accuracy
and protection. Overcurrent protection is implemented
by a simple undervoltage detection scheme and is dis-
abled until soft start has been completed to eliminate
false trips due to output capacitor charging. The SS/EN
pin is held low, as are the DH and DL pins, until the
undervoltage lockout points are exceeded. Once the VCC
and BST pins both rise above their undervoltage lockout
points, the SS capacitor begins to charge, controlling the
duty cycle of the switcher, and therefore slowly ramping
up the switcher output voltage. Once the SS capacitor is
charged, the current limit circuitry is enabled. If a short
circuit is applied , the output will be pulled down below
it’s trip point and shut down. The device may be restarted
by either cycling power, or momentarily pulling SS/EN low.
OUTPUT INDUCTOR - A good starting point for output
filter component selection is to choose an inductor value
that will give an inductor ripple current of approximately
20% of max. output current.
Inductor ripple current is given by:-
ILRIPPLE
=
VO
× ççèæ1 -
VO
VIN
L × fOSC
÷÷øö
So choose inductor value from:-
L
=
5×
VO
×
ççèæ1
-
VO
VIN
IO × fOSC
÷÷øö
OUTPUT CAPACITOR(S) - The output capacitors should
be selected to meet output ripple and transient response
criteria. Output ripple voltage is caused by the inductor
ripple current flowing in the output capacitor’s ESR (There
is also a component due to the inductor ripple current
charging and discharging the output capacitor itself, but
this component is usually small and can often be ignored).
Given a maximum output voltage ripple requirement, ESR
is given by:-
RESR
<
VO
× VRIPPLE × ççèæ1 -
L × fOSC
VO
VIN
÷÷øö
Output voltage transient excursions are a function of load
current transient levels, input and output voltages and
inductor and capacitor values.
Capacitance and RESR values to meet a required tran-
sient condition can be calculated from:-
RESR
<
VT
IT
C
>
L × IT2
2 × VT × VA
where
VA = VIN - VO for negative transients (load application)
and
VA = VO for positive transients (load release)
values for positive and negative transients must be cal-
culated seperately and the worst case value chosen. For
Capacitor values, the calculated value should be doubled
to allow for duty cycle limitation and voltage drop issues.
2003 Semtech Corp.
5
www.semtech.com
5 Page 
POWER MANAGEMENT
Evaluation Board Schematic & Layout
33.33VV- -152VVININ
J2
GND
J6
10
R1
C8
220pF
R7
30k
EN
J11
C11
EMPTY
GND
J7
GND
J5
12V IN
J1
C1 0.1uF
C2
10uF
U1
4 VCC BST 8
1 COMP DH 7
2 SS/EN
5 GND
DL 6
FB 3
SC2612
R3 2.2
R2 2.2
C9
0.1uF
D1
EMPTY
SC2612A/C
www.DataSheet4U.com
C3 C4 C5
1500uF 1500uF 1500uF
Q1
Si4410DY
L1 1uH
Q2
Si4410DY
R5
6.98k
R8
8.06k
C6
150 0uF
1.5V OUT
J4
C10
1500uF
GND
J8
2003 Semtech Corp.
11
www.semtech.com
11 Page | ||
| Páginas | Total 12 Páginas | |
| PDF Descargar | [ Datasheet SC2612C.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| SC2612A | 600kHz/200kHz Step-Down DC/DC Converter | Semtech |
| SC2612C | 600kHz/200kHz Step-Down DC/DC Converter | Semtech |
| SC2612E | 500kHz Step-Down DC/DC Converter | Semtech |
| 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 |