|
|
PDF RT7263A Data sheet ( Hoja de datos )
| Número de pieza | RT7263A | |
| Descripción | Synchronous Step-Down Converter | |
| Fabricantes | Richtek | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de RT7263A (archivo pdf) en la parte inferior de esta página. Total 17 Páginas | ||
|
No Preview Available !
®
RT7263A
3A, 21V 500kHz Synchronous Step-Down Converter
General Description
The RT7263A is a synchronous step-down regulator with
an internal power MOSFET. It achieves 3A of continuous
output current over a wide input supply range with excellent
load and line regulation. Current mode operation provides
fast transient response and eases loop stabilization.
Fault condition protection includes cycle-by-cycle current
limiting and thermal shutdown. An adjustable soft-start
reduces the stress on the input source at startup.
The RT7263A requires a minimal number of readily
available external components, providing a compact
solution.
Ordering Information
RT7263A
Package Type
QW : WDFN-14L 4x3 (W-Type)
SP : SOP-8 (Exposed Pad-Option 2)
Lead Plating System
Z : ECO (Ecological Element with
Halogen Free and Pb free)
Note :
Richtek products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
Features
z Wide Input Range : 4.5V to 21V
z Adjustable Output from 0.808V to 15V
z 3A Output Current
z 120mΩ/40mΩ Internal Power MOSFET Switch
z Internal Compensation Minimizes External Parts
z 500kHz Fixed Switching Frequency
z Synchronized External Clock from 300kHz to 2MHz
z Adjustable Soft-Start
z Cycle-by-Cycle Over Current Limit
z Thermal Shutdown Protection
z Available in SOP-8 (Exposed Pad) and WDFN-14L
4x3 Packages
z RoHS Compliant and Halogen Free
Applications
z Distributive Power Systems
z Battery Charger
z DSL Modems
z Pre-Regulator for Linear Regulators
Simplified Application Circuit
VIN
Chip Enable
VIN BOOT
CIN RT7263A
SW
EN/SYNC
VCC
FB
CC GND
CBOOT L
RT R1
R2
VOUT
COUT
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS7263A-01 September 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1
Free Datasheet http://www.datasheet4u.com/
1 page  
RT7263A
Absolute Maximum Ratings (Note 1)
z Supply Input Voltage, VIN ---------------------------------------------------------------------------------- −0.3V to 26V
z Switch Voltage, SW ----------------------------------------------------------------------------------------- −0.3V to (VIN + 0.3V)
z Boot Voltage, BOOT ----------------------------------------------------------------------------------------- (SW − 0.3V) to (SW + 6V)
z Other Pins ------------------------------------------------------------------------------------------------------ −0.3V to 6V
z Power Dissipation, PD @ TA = 25°C
WDFN-14L 4x3 ------------------------------------------------------------------------------------------------ 1.667W
SOP-8 (Exposed Pad) -------------------------------------------------------------------------------------- 1.333W
z Package Thermal Resistance (Note 2)
WDFN-14L 4x3, θJA ------------------------------------------------------------------------------------------ 60°C/W
WDFN-14L 4x3, θJC ------------------------------------------------------------------------------------------ 7°C/W
SOP-8 (Exposed Pad), θJA --------------------------------------------------------------------------------- 75°C/W
SOP-8 (Exposed Pad), θJC -------------------------------------------------------------------------------- 15°C/W
z Junction Temperature ---------------------------------------------------------------------------------------- 150°C
z Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------ 260°C
z Storage Temperature Range ------------------------------------------------------------------------------- −65°C to 150°C
z ESD Susceptibility (Note 3)
HBM (Human Body Model) --------------------------------------------------------------------------------- 2kV
Recommended Operating Conditions (Note 4)
z Supply Input Voltage, VIN ---------------------------------------------------------------------------------- 4.5V to 21V
z Junction Temperature Range ------------------------------------------------------------------------------- −40°C to 125°C
z Ambient Temperature Range ------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
(VIN = 12V, TA = 25°C unless otherwise specified)
Parameter
Symbol
Shutdown Current
ISHDN
Quiescent Current
IQ
Upper Switch On Resistance RDS(ON)1
Lower Switch On Resistance RDS(ON)2
Switch Leakage
ILEAK
Current Limit
Oscillator Frequency
ILIMIT
fSW
Short Circuit Frequency
Maximum Duty Cycle
DMAX
Minimum On Time
tON
Feedback Voltage
VFB
Feedback Current
EN Voltage
Logic-High
Logic-Low
IFB
VIH
VIL
Test Conditions
VEN = 0
VEN = 2V, VFB = 1V
VEN = 0V, VSW = 0V or 12V
VBOOT − VSW = 4.8V
VFB = 0.75V
VFB = 0V
VFB = 0.8V
4.5V ≤ VIN ≤ 21V
Min
--
--
--
--
--
5.4
425
--
--
--
0.796
--
2
--
Typ
0
0.7
120
40
0
6.5
500
150
90
100
0.808
10
--
--
Max
1
--
--
--
10
--
575
--
--
--
0.82
50
5.5
0.4
Unit
μA
mA
mΩ
mΩ
μA
A
kHz
kHz
%
ns
V
nA
V
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS7263A-01 September 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
5
Free Datasheet http://www.datasheet4u.com/
5 Page 
Application Information
The IC is a synchronous high voltage step-down converter
that can support the input voltage range from 4.5V to 21V
and the output current can be up to 3A.
Output Voltage Setting
The output voltage is set by an external resistive divider
according to the following equation :
VOUT
=
VFB
⎛⎜⎝1+
R1
R2
⎞⎟⎠
where VFB is the feedback reference voltage 0.808V (typ.).
The resistive divider allows the FB pin to sense a fraction
of the output voltage as shown in Figure 1.
VOUT
FB
RT7263A
GND
R1
R2
Figure 1. Output Voltage Setting
External Bootstrap Diode
Connect a 100nF low ESR ceramic capacitor between
the BOOT pin and SW pin as shown in Figure 2. This
capacitor provides the gate driver voltage for the high side
MOSFET. It is recommended to add an external bootstrap
diode between an external 5V and BOOT pin for efficiency
improvement when input voltage is lower than 5.5V or duty
ratio is higher than 65% .The bootstrap diode can be a
low cost one such as IN4148 or BAT54. The external 5V
can be a 5V fixed input from system or a 5V output of the
IC. Note that the external boot voltage must be lower than
5.5V.
5V
BOOT
RT7263A
SW
100nF
Figure 2. External Bootstrap Diode
RT7263A
Soft-Start for WDFN-14L Package
The RT7263AZQW (WDFN-14L package) contains an
external soft-start clamp that gradually raises the output
voltage. The soft-start timing is programmed by the external
capacitor between SS pin and GND. The chip provides an
internal 10μA charge current for the external capacitor. If
47nF capacitor is used to set the soft-start, the period will
be 4.7ms (typ.).
Soft-Start for SOP-8 (Exposed Pad) Package
The RT7263AZSP (SOP-8 (Exposed Pad) package)
contains an internal soft-start function to prevent large
inrush current and output voltage overshoot when the
converter starts up. Soft-start automatically begins once
the chip is enabled. During soft-start, the internal soft-
start capacitor becomes charged and generates a linear
ramping up voltage across the capacitor. This voltage
clamps the voltage at the internal reference, causing the
duty pulse width to increase slowly and in turn reduce the
output surge current. The typical soft-start time for this IC
is set at 2ms.
Under Voltage Lockout Threshold
The IC includes an input Under Voltage Lockout Protection
(UVLO). If the input voltage exceeds the UVLO rising
threshold voltage (4.2V), the converter resets and prepares
the PWM for operation. If the input voltage falls below the
UVLO falling threshold voltage (3.8V) during normal
operation, the device stops switching. The UVLO rising
and falling threshold voltage includes a hysteresis to
prevent noise caused reset.
Chip Enable Operation
The EN pin is the chip enable input. Pulling the EN pin
low (<0.4V) will shutdown the device. During shutdown
mode, the RT7263A quiescent current drops to lower than
1μA. Driving the EN pin high (2V < EN < 5.5V) will turn on
the device again. For external timing control, the EN pin
can also be externally pulled high by adding a REN resistor
and CEN capacitor from the VIN pin (see Figure 3).
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS7263A-01 September 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
11
Free Datasheet http://www.datasheet4u.com/
11 Page | ||
| Páginas | Total 17 Páginas | |
| PDF Descargar | [ Datasheet RT7263A.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| RT7263A | Synchronous Step-Down Converter | Richtek |
| RT7263B | Synchronous Step-Down Converter | Richtek |
| RT7263E | Synchronous Step-Down Converter | Richtek |
| 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 |