MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER

MP2612 Rev. 1.0

www.MonolithicPower.com

10

9/7/2011

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PIN FUNCTIONS

Pin #

Name

Description

1

NTC

Thermistor Input. Connect a resistor from this pin to the pin VREF33 and the Thermistor

from this pin to ground.

2

ACOK

Valid Input Supply Indicator. A logic LOW on this pin indicates the presence of a valid input

supply.

3

CHGOK

Charging Completion Indicator. A logic LOW indicates charging operation. The pin will

become an open drain once the charging is complete.

4

VREF33

Internal linear regulator 3.3V reference output. Bypass to GND with a 1μF ceramic

capacitor.

5

VREF25 Internal linear 2.5V reference circuit. PLEASE KEEP THIS PIN FLOATING.

6

EN

On/Off Control Input.

7

CELLS

Command Input for the number of Li-Ion Cells. Connect this pin to VREF33 for 3-cell

operation or ground the pin for 2-cell operation. DO NOT LEAVE THIS PIN FLOAT.

8

COMPV V-LOOP Compensation. Decouple this pin with a capacitor and a resistor.

9

COMPI I-LOOP Compensation. Decouple this pin with a capacitor and a resistor.

10

BATT

Positive Battery Terminal.

11

CSP

full charge current is:





mΩ

RS1

200mV

A

I

CHG



.

12

GND

Ground. This pin is the voltage reference for the regulated output voltage. For this reason

care must be taken in its layout. This node should be placed outside of the switching diode

(D2) to the input ground path to prevent switching current spikes from inducing voltage

noise into the part.

13

TMR

Set time constant. 0.1uA current charges and discharges the external cap.

14

BST

Bootstrap. This capacitor is needed to drive the power switch’s gate above the supply

voltage. It is connected between SW and BS pins to form a floating supply across the power

switch driver.

15

SW

Switch Output.

16

IN

Supply Voltage. The MP2612 operates from a 9V to 24V unregulated input to charge 2~3

cell li-ion battery. Capacitor is needed to prevent large voltage spikes from appearing at the

input.