1.5MHz 700mA Synchronous Step-Down Converter with Low Quiescent Current
◼ General Description
The OCP2158 is a 1.5MHz constant frequency, high
efficiency, slope compensated current mode PWM
step-down converter. The devices integrate a main
switch and a synchronous rectifier for high efficiency
without an external Schottky diode. The OCP2158 can
operate from a 2.0V to 6.5V input voltage and is ideal
for powering portable equipment that runs from a single
cell lithium-ion (Li+) battery. It can supply 700mA
output current and can also run at 100% duty cycle for
low dropout operation, extending battery life in portable
The OCP2158 features a Power Saving Mode which
reduces quiescent current to just 30μA and significantly
improves efficiency at light load.
*The OCP2158 is offered in a low profile (1mm) 5-pin,
SOT package, and is available in an adjustable version
and fixed output voltage of 1.2V, 1.5V and 1.8V.
⚫ Cellular and Smart Phones
⚫ MP3 Player
⚫ DSP Core Supplies
⚫ Digital Still Cameras
⚫ Portable instruments
⚫ High Efficiency : Up to 96%
⚫ 1.5MHz Constant Switching Frequency
⚫ 700mA Output Current at VIN=3.0V
⚫ Integrated Main switch and synchronous rectifier
⚫ No Schottky Diode Required
⚫ 2.0V to 6.5V Input Voltage Range
⚫ Output Voltage as low as 0.6V
⚫ 100% Duty Cycle in Dropout
⚫ Low Quiescent Current : 30μA
⚫ ＜1μA Shutdown Current
⚫ Slope Compensated Current Mode Control for
Excellent Line and Load Transient Response
⚫ Short Circuit and Thermal Fault Protection
⚫ Space Saving 5-pin Thin SOT23 package
◼ Pin Configuration
◼ Pin Description
Regulator Enable control input. Drive RUN above 1.5V to turn on the part.
Drive RUN below 0.3V to turn it off. In shutdown, all functions are disable
drawing ＜1μA supply current. Do not leave RUN floating.
Power Switch Output. It is the Switch node connection to inductor. This pin
connects to the drains of the internal P-CH and N-CH MOSFET switches.
Supply Input Pin. Must be closely decoupled to GND, pin2, with a 2.2μF or
greater ceramic capacitor.
VFB (OCP2158): Feedback Input Pin. Connected FB to the center point of
the external resistor divider. The feedback threshold voltage is 0.6V.
VOUT (OCP2158-1.2/1.5/1.8): Output Voltage Feedback Pin. An internal
resistive divider divides the output voltage down for comparison to the
internal reference voltage.
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Rev.1.3. Feb .27, 2018