MP3213 – 700KHZ/1.3MHZ BOOST CONVERTER WITH A 3.5A SWITCH
PIN FUNCTIONS
Pin #
1
2
3
4
5
6
7
8
Name Description
COMP Compensation Pin. Connect a capacitor and resistor in series to ground for loop stability.
FB
Feedback Input. Reference voltage is 1.25V. Connect a resistor divider to this pin.
Regulator On/Off Control Input. A high input at EN turns on the converter, and a low input turns
EN
it off. When not used, connect EN to the input source (through a 100kΩ pull-up resistor if V
IN
>
6V) for automatic startup.
EN cannot be left floating.
GND Ground. The exposed pad is connected to GND.
Power Switch Output. SW is the drain of the internal MOSFET switch. Connect the power
SW
inductor and output rectifier to SW. SW can swing between GND and 25V.
IN
Input Supply Pin. IN must be locally bypassed.
Frequency Select Pin. Tie to IN (through a 100kΩ resistor if V
IN
> 6V) for 1.3MHz operation or to
FSEL
GND for 700KHz operation.
Soft-Start Control Pin. Connect a soft-start capacitor to this pin. The soft-start capacitor is
SS
charged with a constant current of 6µA. Leave SS disconnected if the soft-start is not used.
OPERATION
The MP3213 uses a constant frequency, peak
current mode boost regulation architecture to
regulate the feedback voltage.
IN
INTERNAL REGULATOR
AND ENABLE CIRCUITRY
OSCILLATOR
The operation of the MP3213 can be
understood by referring to the block diagram of
Figure 1.
EN
FSEL
SW
+
PWM
CONTROL
LOGIC
CURRENT
SENSE
AMP
--
+
--
--
GM
GND
FB
SS
+
1.25V
COMP
Figure 1—Functional Block Diagram
MP3213 Rev. 1.1
5/12/2006
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
5
MPS [ MONOLITHIC POWER SYSTEMS ]
