REV. A
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a
ADP3820
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 1999
Lithium-Ion
Battery Charger
FUNCTIONAL BLOCK DIAGRAM
V
IN
IS
GATE
V
OUT
SD
50mV
+
–
BIAS
V
REF
ADP3820
GND
FEATURES
61% Total Accuracy
630 mA Typical Quiescent Current
Shutdown Current: 1 mA (Typical)
Stable with 10 mF Load Capacitor
4.5 V to 15 V Input Operating Range
Integrated Reverse Leakage Protection
6-Lead SOT-23-6 and 8-Lead SO-8 Packages
Programmable Charge Current
–208C to +858C Ambient Temperature Range
Internal Gate-to-Source Protective Clamp
APPLICATIONS
Li-Ion Battery Chargers
Desktop Computers
Hand-Held Instruments
Cellular Telephones
Battery Operated Devices
GENERAL DESCRIPTION
The ADP3820 is a precision single cell Li-Ion battery charge
controller that can be used with an external Power PMOS de-
vice to form a two-chip, low cost, low dropout linear battery
charger. It is available in two voltage options to accommodate
Li-Ion batteries with coke or graphite anodes. The ADP3820’s
high accuracy (– 1%) low shutdown current (1 m A) and easy
charge current programming make this device especially attrac-
tive as a battery charge controller.
Charge current can be set by an external resistor. For example,
50 mW of resistance can be used to set the charge current to
1 A. Additional features of this device include foldback current
limit, overload recovery, and a gate-to-source voltage clamp to
protect the external MOSFET. The proprietary circuit also
minimizes the reverse leakage current from the battery if the
input voltage of the charger is disconnected. This feature elimi-
nates the need for an external serial blocking diode.
The ADP3820 operates with a wide input voltage range from
4.5 V to 15 V. It is specified over the industrial temperature
range of –20 C to +85 C and is available in the ultrasmall
6-lead surface mount SOT-23-6 and 8-lead SOIC packages.
C1
10mF
+
–
R1
10kV
V
IN
+5V
R
S
50mV
22mF
V
OUT
Li-Ion
BATTERY
I
O
= 1A
NDP6020P
GND
IS GATE
V
IN
SD
V
OUT
ADP3820-xx
Figure 1. Li-Ion Charger Application Circuit