MAX8903A Maxim Integrated Products, MAX8903A Datasheet - Page 12

• Manufacturer Part Number: MAX8903A
• Description: 2A 1-Cell Li+ DC-DC Charger for USB* and Adapter Power
• Manufacturer: Maxim Integrated Products

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2A 1-Cell Li+ DC-DC Charger for USB*
and Adapter Power
The MAX8903A is a dual input charger with a 16V input
for a wide range of DC sources and USB inputs. The IC
includes a high-voltage (16V) input DC-DC step-down
converter that reduces charger power dissipation while
also supplying power to the system load. The step-
down converter supplies up to 2A to the system, the
battery, or a combination of both.
Figure 2. Typical Application Circuit Using a Separate DC and USB Connector
12
______________________________________________________________________________________
VBUS
GND
ADAPTER
USB
USB SUSPEND
Circuit Description
CHARGE ON
500mA
4.7μF
OFF
100mA
1μH
0.15μF
C
C
0.1μF
L1
DC
BST
C
4.7μF
C
CT
USB
TO VL
17
26
14
10
27
28
25
15
1
2
3
4
6
7
5
LX
IUSB
USUS
CT
LX
DCM
CEN
PG
PG
DC
DC
BST
CS
CS
USB
MAX8903A
A USB charge input can charge the battery and power
the system from a USB power source. When powered
from USB or the DC input, system load current peaks
that exceed what can be supplied by the input are sup-
plemented by the battery.
The MAX8903A also manages load switching from the
battery to and from an external power source with an
on-chip 50mΩ MOSFET. This switch also helps support
load peaks using battery power when the input source
is overloaded.
DOK
CHG
THM
UOK
ISET
GND
SYS
SYS
BAT
BAT
FLT
IDC
VL
13
18
19
11
24
23
20
9
16
12
8
22
21
R
4 x 100kΩ
R
R
PU
ISET
IDC
C
10μF
RT
10kΩ
C
10μF
BAT
NTC
10kΩ
SYS
TO SYSTEM
LOAD
1-CELL
LI+
TO VL
FAULT
OUTPUT
USB PWR OK
CHARGE
INDICATOR
DC PWR OK