MAX8903A–E/G/H/J/N/Y

2A 1-Cell Li+ DC-DC Chargers

for USB and Adapter Power

11

Maxim Integrated

Typical Operating Characteristics (continued)

100

µs/div

USB DISCONNECT WITH NO DC

Ω)

2V/div

MAX8903A toc26

5V/div

500mA/div

500mA/div

3.6V

475mA

5V

144mA

-330mA

200

µs/div

USB SUSPEND

5V/div

MAX8903A toc27

500mA/div

2V/div

500mA/div

475mA

-475mA

3V

0V

0A

3.7V

0A

200

µs/div

USB RESUME

5V/div

MAX8903A toc28

500mA/div

2V/div

500mA/div

475mA

-475mA

3V

0V

0A

3.6V

0A

3.6V

3.8V

BATTERY

CHARGER

SOFT-START

CHARGING

Pin Description

PIN

NAME

FUNCTION

1, 2

PG

Power Ground for Step-Down Low-Side Synchronous n-Channel MOSFET. Both PG pins must be

connected together externally.

3, 4

DC

DC Power Input. DC is capable of delivering up to 2A to SYS. DC supports both AC adapter and USB

inputs. The DC current limit is set through DCM, IUSB, or IDC depending on the input source used. See

Table 2. Both DC pins must be connected together externally. Connect at least a 4.7µF ceramic capacitor

from DC to PG.

5

DCM

Current-Limit Mode Setting for the DC Power Input. When logic-high, the DC input current limit is set by

the resistance from IDC to GND. When logic-low, the DC input current limit is internally programmed to

500mA or 100mA, as set by the IUSB logic input. There is an internal diode from DCM (anode) to DC

(cathode) as shown in Figure 1.

6

BST

High-Side MOSFET Driver Supply. Bypass BST to LX with a 0.1µF ceramic capacitor.

7

IUSB

USB Current-Limit Set Input. Drive IUSB logic-low to set the USB current limit to 100mA. Drive IUSB logic-

high to set the USB current limit to 500mA.

8

DOK

DC Power-OK Output. Active-low open-drain output pulls low when a valid input is detected at DC.

DOK

is still valid when the charger is disabled (

CEN high).

9VL

Logic LDO Output. VL is the output of an LDO that powers the MAX8903_ internal circuitry and charges

the BST capacitor. Connect a 1µF ceramic capacitor from VL to GND.

10

CT

Connect to GND to disable the timer.

11

IDC

step-down regulator from 0.5A to 2A when DCM is logic-high.

12

GND

Ground. GND is the low-noise ground connection for the internal circuitry.