SC189
2.5MHz, 1.5A Synchronous
Step Down Regulator
POWER MANAGEMENT
Features
Description
VIN Range: 2.9 – 5.5V
VOUT Options: 1.0 - 3.3V
Up to 1.5A Output Current
Ultra-Small Footprint, <1mm Height Solution
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
Available in SOT23-5 package and 2mm x 2mm x
0.6mm thermally enhanced MLPD-UT6 package
-40 to +85°C Temperature Range
Fully WEEE and RoHS Compliant
The SC189 is a high efficiency, synchronous step-down
regulator providing up to 1.5A output current in either
an ultra-small 2mm x 2mm, low profile package or a low
cost 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. Total footprint of 25mm2 can
be achieved - making the SC189 the ideal solution for
high density systems. Solution height of <1mm is also
possible.
Up to 93% efficiency is achieved with low RDS(ON) internal
switches. PWM constant frequency operation ensures
low output ripple across the load range. 100% duty-cycle
provides 360mV dropout voltage at 1.5A which extends
the minimum input voltage for 2.5V and 3.3V outputs.
Excellent transient response is achieved with no external
compensation components.
The SC189 provides input under-voltage, output overvoltage, 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.
Applications
Bluetooth Radios
DSC and PMPs
GPS Devices
xDSL Systems
POL Regulators
Portable HDD
Wireless LAN
The SC189 is available in SOT23-5 and a thermally
enhanced 2mm x 2mm x 0.6mm MLPD-UT6 package.
Typical Application Circuit
Total PCB Area ~25mm2
SC189C
VIN
2.9V to 5.5V
VIN
CIN
10µF
LX
EN
VOUT
L
1µH
L
Chip
VOUT
1.20V/1.5A
COUT
22µF
COUT
0805
GND
SC189
CIN
0603
Actual Size
August 27, 2010
www.semtech.com
