SC4626 Datasheet, PDF (1/21 Pages) Semtech Corporation – 2.5MHz, 1A Synchronous Step Down Regulator in SOT23-5

POWER MANAGEMENT
Features
 V_IN Range: 2.9 – 5.5V
 V_OUT Options: 1.0 - 3.3V
 Up to 1A Output Current
 2.5MHz Switching Frequency
 Efficiency Up to 93%
 Low Output Noise Across Load Range
 Excellent Transient Response
 Start Up into Pre-Bias Output
 100% Duty-Cycle Low Dropout Operation
 <1µA Shutdown Current
 Internal Soft Start
 Input Under-Voltage Lockout
 Output Over-Voltage, Current Limit Protection
 Over-Temperature Protection
 Adjustable Output Voltage
 SOT23-5 Package
 -40 to 85°C Temperature Range
 Fully WEEE and RoHS Compliant
Applications
 Bluetooth Radios
 DSC and PMPs
 GPS Devices
 xDSL Systems
 POL Regulators
 Portable HDD
 Wireless LAN
SC4626
2.5MHz, 1A Synchronous Step
Down Regulator in SOT23-5
Description
The SC4626 is a high efficiency, synchronous step-down
regulator providing up to 1A output current in a SOT23-
5 package. The device requires only three external filter
components for a complete step-down regulator solution.
The input voltage range is 2.9 to 5.5V with either factory
programmed outputs from 1.0 to 3.3V or adjustable
output via an external resistor divider.
The converter operates at fixed 2.5MHz switching
frequency allowing small L/C filtering components.
The voltage mode architecture is compatible with chip
inductors and capacitors for minimum PCB footprint and
lowest overall system cost.
Up to 93% efficiency is achieved with low R_DS(ON) internal
switches. PWM constant frequency operation ensures
low output ripple across the load range. 100% duty-cycle
provides 300mV dropout voltage at 1A which extends
the minimum input voltage for 2.5V and 3.3V outputs.
Excellent transient response is achieved with no external
compensation components.
The SC4626 provides input under-voltage, output over-
voltage, output short circuit and over-temperature
protection to safeguard the device and system under fault
conditions. The regulator provides integrated soft-start to
minimize inrush currents. Standby quiescient current is
less than 1µA.
The SC4626 is available in a SOT23-5 package rated for -40
to +85°C ambient temperature range.
Typical Application Circuit
V_IN
2.9V to 5.5V
C_IN
10µF
VIN
LX
GND
L
2.2µH
C_OUT
10µF
V_OUT
1.20V/1A
Enable
April 23, 2009
EN VOUT
SC4626C

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