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dc705af
DEMO MANUAL DC705A
Description
LTC4053EMSE-4.2
Lithium-Ion Linear Battery Charger
with Thermal Regulation
Demonstration circuit DC705 is a complete constant-
current, constant-voltage battery charger designed to
charge one Lithium-Ion cell. The LT C
®
4053EMSE-4.2 used
on this demo circuit features an internal P-channel power
MOSFET with a unique thermal feedback loop that reduces
the output current under high ambient temperature and/or
high power dissipation conditions. This feature allows the
charger to provide higher charge currents under normal
conditions and still provide safe charging under abnormal
conditions such as high ambient temperature, high input
voltage or low battery voltage. The IC is available in a 10-pin
MSOP thermally enhanced package featuring an exposed
bottom-side metal pad for soldering to the PC board.
Other features include:
• Preset float voltage of 4.2V ±1%
• 1A and 0.5A constant current selected by a jumper
• Capable of charging directly from USB power
• 3-hour charge termination timer. This timer can be set
for other time periods through a capacitor change. For
instance, you may want to use a much shorter period
(on the order of 30 seconds) when evaluating the board
with a battery simulator instead of a real Li-Ion battery.
• Charge current monitor
output can be used for gas
gauging
• Manual shutdown
• Low
battery drain current when input supply is removed
• No isolation diode or current sense resistor required
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
• C/10 trickle charge for deeply discharged batteries
• Auto recharge when battery voltage drops below pre-
set threshold
• Input power OK LED indicator (ACPR)
• C/10 charge LED indicator (CHRG)
• Fault LED indicator for “out of temp range” (FAULT)
Small surface mount components are used to minimize
board space and height with the circuitry occupying ap
-
proximately 0.15 square inches
of board space with a
height of 0.054 inches (1.4mm).
Table 1. Typical Demo Board Specifications
Input Voltage Range V
IN
4.25V to 7V (Upper Range Limited
by PC Board Dissipation)
Output Voltage V
BAT
(Constant
Voltage Mode)
4.2V ±1%
Output Current I
BAT
(Constant
Current Mode)
1A ±8%, 0.5A ±8% (Selected by
Jumper)
Current Monitor Output 1.5V ±5% at Full Current
Output Current I
BAT
(Trickle Current
Mode)
100mA ±20%, 50mA ±20%
C/10 CHRG LED Threshold Level 100mA ±20%, 50mA ±25%
Circuit Board Temperature in
Thermal Feedback Mode
60°C to 70°C
Trickle Charge Threshold Voltage 2.457V
Battery Drain Current with V
IN
Removed
< 1µA
Design files for this circuit board are available at
http://www.linear.com/demo/DC705A
