Datasheet

MAX8903A–E/G/H/J/N/Y
2A 1-Cell Li+ DC-DC Chargers
for USB and Adapter Power
14
Maxim Integrated
Circuit Description
The MAX8903_ 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.
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 MAX8903_ 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.
PG
PG
DC
DC
BST
LX
LX
CS
CS
SYS
SYS
BAT
BAT
FLT
UOK
DOK
FAULT
OUTPUT
USB PWR OK
DC PWR OK
TO VL
R
PU
4 x 100kΩ
18
19
8
24
23
21
20
1
2
3
4
6
27
28
25
26
17 USB
ISET
IDC
R
ISET
R
IDC
DCM
THM
CEN
IUSB
GND
EP
NTC
10kΩ
USUS
5
9
16
12
CHARGE ON
OFF
100mA
500mA
USB SUSPEND
14
7
15
TO SYSTEM
LOAD
CHG
22
CHARGE
INDICATOR
C
DC
4.7µF
CT
C
CT
0.15µF
ADAPTER
VBUS
GND
C
BST
0.1µF
L1
1µH
13
11
C
USB
4.7µF
USB
(SEE TABLE 5 FOR
INDUCTOR SELECTION)
10
R
T
10kΩ
TO DC
1-CELL
LI+
C
BAT
10µF
C
VL
1µF
C
SYS
(SEE TABLE 6 FOR C
SYS
SELECTION)
VL
MAX8903_
Figure 2. Typical Application Circuit Using a Separate DC and USB Connector