MP26053 – 28V, 1A LINEAR BATTERY CHARGER WITH TRICKLE CHARGE AND TIMER

MP26053 Rev. 0.9

www.MonolithicPower.com

4

8/25/2008

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PIN FUNCTIONS

Pin #

Name

Description

1

VIN

Input Supply Pin. VIN receives the AC adapter or USB supply voltage.

2

ACOK

Open-Drain Fault Status Indicator. This pin is high under any fault conditions.

3

CHG

Open-Drain Charge Indicator. This pin is low during charging, is high after battery full

or termination, and is toggling when the battery is in fault condition.

4

TMR

Oscillator Period Timer. Connect a timing capacitor between this pin and GND

to set the oscillator period. The total charge time:

TMR

3

)

SEC

(

C

*

10

22

T

×

=

,

5

GND, Exposed

Pad

The exposed pad and GND pin must be connected to the same ground plane.

6

SHDN

Charger IC Enable. An input “Low” signal at this pin or pin floating will enable the IC.

7

SS

Soft-Start. Connect a capacitor to ground to set the soft-start time.

8

ISET

Constant Charge Current Program Pin. Connect this pin to an external resistor to

program the charging current in CC Mode.

9

NTC

Negative Temperature Coefficient (NTC) Thermistor Pin. Connect a 50kΩ resistor from

this pin to the VIN pin and a 10kΩ NTC resistor (within the battery pack) from this pin

to ground. If NTC function is not used, replace NTC resistor with a regular 10kΩ

resistor from this pin to ground.

Do not leave this pin floating.

10

BATT

Charger Output.

BLOCK DIAGRAM

BATTERY

CHARGE

CONTROL

7

8

9

4

1

10

3

2

5

6

TMR

ISET

NTC

SS

IN

BATT

CHG

ACOK

GND

8.2V

8.2V

SHDN

+

_

ON OFF

Figure 1—Functional Block Diagram