MIC79110
Simple 1.2A Linear Li-Ion Battery Charger
General Description
The Micrel MIC79110 is a simple and accurate lithium ion
battery charger. The part features a built-in pass transistor,
precision programmable current limiting (±5%), and
precision voltage termination (±0.75% over temperature).
The MIC79110 packs full functionality into a small space.
Other features of the MIC79110 include two independent
indicators: a digital End-of-Charge signal that is
programmable with a resistor to ground, and an analog
current output that is proportional to the output current,
allowing for monitoring of the actual charging current.
Additional features include very low dropout (550mV over
the temperature range), thermal shutdown, and reverse
polarity protection. In the event the input voltage to the
charger is disconnected, the MIC79110 also provides
minimal reverse-current and reversed-battery protection.
Available in both
fixed
4.2V and adjustable outputs, the
MIC79110 is offered in the leadless 10-pin 3mm x 3mm
MLF
®
with an operating junction temperature range of
–40˚C to +125˚C.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Features
•
Input voltage range: 2.5V to 16V
•
High output voltage accuracy of ±0.75%
over –5°C to +60˚C
•
Current limit ±5% accurate from –5°C
≤
T
J
≤
+ 125°C
•
Programmable end-of-charge flag
•
Analog output proportional to output current
•
Adjustable and fixed 4.2V output
•
Low dropout voltage of 550mV at 700mA load, over
temperature
•
1.2A max charge current
•
Excellent line and load regulation specifications
•
Reverse current protection
•
Thermal shutdown and current limit protection
•
Tiny 10-Pin 3mm
×
3mm MLF
®
package
•
Junction temperature range: –40°C to +125°C
Applications
•
Cellular phones
•
PDAs
•
Digital cameras
•
Camcorders
•
MP3 players
•
Notebook PCs
•
Portable Meters
•
Cradle chargers
•
Car chargers
•
Battery packs
___________________________________________________________________________________________________________
Typical Application
MIC79110
V
IN
SHUTDOWN
ENABLE
V
IN
SD
R
EOC
R
SET
GND
BAT
SNS
D
EOC
A
CHG
4.2V
BAT
4.2V
Li-Ion
Cell
MIC79110 Typical Application
MLF and
MicroLeadFrame
are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 2007
M9999-102507
Micrel, Inc.
MIC79110
Ordering Information
Part Number
Standard
MIC79110-4.2BML
MIC79110BML
Marking
L942
L9AA
Pb-Free
MIC79110-4.2YML
MIC79110YML
Marking
L942*
L9AA*
Voltage
4.2V
Adj.
Junction
Temp. Range
–40° to +125°C
–40° to +125°C
Package
10-pin 3×3 MLF
®
10-pin 3×3 MLF
®
* Pb-Free “Y” indicator is added to the device mark after LOGO.
Pin Configuration
SD 1
R
SET
2
SNS 3
BAT
4
10 GND
9 R
EOC
8 D
EOC
7 A
CHG
6 V
IN
SD 1
R
SET
2
ADJ 3
BAT
4
10 GND
9
8
7
6
R
EOC
D
EOC
A
CHG
V
IN
V
IN
5
V
IN
5
Fixed Output
10-Pin 3mm × 3mm MLF
®
(ML)
Adjustable Output
10-Pin 3mm × 3mm MLF
®
(ML)
Pin Description
Pin Number
1
2
3
3
4
5, 6
7
8
Pin Name
SD
RSET
SNS
ADJ
BAT
VIN
ACHG
DEOC
Pin Function
Shutdown Input. Logic High = Off; Logic Low = On.
Current limit: Sets constant current limit via an external resistor to ground.
IR
SET
= (0.2V/R
SET
)
×
1000.
(Fixed voltage only): Sense output, connect directly to battery.
(Adjustable voltage only): Feedback input.
Battery Terminal. Connect to single-cell lithium-ion battery.
Input supply pin.
Analog Charge Indicator Output: Current source who’s output current is equal to
1/1000 of the BAT pin current.
Digital End-of-Charge Output: N-Ch open drain output. Low indicates charging,
a current that is higher than the programmed current set by R
EOC
is charging the
battery. When the current drops to less than the current set by R
EOC
, the output
goes high impedance, indicating end-of-charge.
End-of-Charge Set: Sets end-of-charge current threshold via an external resistor
to ground. I
EOC
= (0.2V/R
EOC
)
×
1000.
Ground
9
10
REOC
GND
October 2007
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M9999-102507
Micrel, Inc.
MIC79110
Absolute Maximum Ratings
(1)
Input Supply Voltage (V
IN
).................................... 0V to 18V
Shutdown Input Voltage (V) ................................. 0V to 10V
Output Voltage (ADJ) .....................................................10V
Power Dissipation ...................................Internally Limited
Junction Temperature ...............................–40°C to +125°C
Operating Ratings
(2)
Input Supply Voltage ........................................ 2.5V to 16V
Shutdown Input Voltage (V) ................................... 0V to 7V
Output Voltage (ADJ) ....................................................9.6V
Junction Temperature Range (T
J
)............. –40°C to +125°C
θ
JA
(MLF-10) .......................................................... 60°C
θ
JC
(MLF-10) ............................................................ 2°C
Electrical Characteristics
(4)
T
A
= 25°C with V
IN
= V
OUT
+ 1V; I
LOAD
= 100µA; C
BATT
= 10µF; SD = 0V; R
SET
=1kΩ.
Bold
values indicate –40ºC < T
J
< +125°C; unless
otherwise specified.
Parameter
Output Voltage Accuracy
ADJ Pin Voltage Accuracy
Line Regulation
Load Regulation
Dropout Voltage(3)
Ground Current
V
IN
Pin Current
Shutdown Pin Current
Shutdown Input Threshold
Shutdown Hysteresis
Current Limit Accuracy
(4, 5)
V
IN
= V
OUT
+ 1V to 16V @ I
LOAD
= 50mA
I
LOAD
= 0.1mA to 1A
I
LOAD
= 100mA, R
SET
= 167Ω
I
LOAD
= 700mA, R
SET
= 167Ω
I
LOAD
= 10mA, R
SET
= 167Ω
I
LOAD
= 700mA, R
SET
= 167Ω
SD = V
IN
SD = 5.2V, V
BAT
= 0
Logic High, regulator off
Logic Low, regulator on
60
V
OUT
= 0.9
×
V
NOM
; I
OUT
= 1.2A,
R
SET
= 167Ω, T
J
= –40°C to +85°C
V
OUT
= 0.9
×
V
NOM
; I
OUT
= 0.1A,
R
SET
= 2kΩ
-5
-20
0.1
R
SET
shorted to ground, V
BAT
= 0.9
×
V
NOM
V
IN
= High impedance or ground
35
30
50
40
1.25
1.65
4.2
50
70
0.74
0.1
150
0.5
37
800
1.0
46
950
190
2.0
55
1150
+5
+20
1.2
2.5
20
65
70
95
100
0.95
1.1
0.9
Condition
Variation from V
OUT
= 4.2V; T
J
= –5°C to +60°C; I
LOAD
= 50mA
Min
-0.75
-1.5
0.5955
-0.1
0.3
160
375
2
24
120
0.1
250
550
3
35
300
5
Typ
Max
+0.75
+1.5
0.6045
+0.1
Units
%
%
V
%/V
%
mV
mV
mA
mA
µA
µA
V
V
mV
%
%
A
A
µA
mA
mA
mA
mA
V
µA
Ω
mA
µA
µA
0.6
Current Limit Setpoint
(5)
Range
Maximum Current Limit
V
BAT
Reverse Current
Digital End–of–Charge (D
EOC
) Output
I
EOC (6, 7)
R
EOC
= 4kΩ Current Falling
I
EOC (6, 7)
D
EOC
Logic–Low Voltage
D
EOC
Leakage Current
D
EOC
On Resistance
R
EOC
Maximum Current Limit
R
EOC
= 4kΩ Current Rising
I
DEOC
= 5mA, I
BAT
= 700mA
Logic High = V
IN
= 16V
V
IN
= +5V
R
EOC
shorted to ground
Analog Charge Indicator (A
CHG
) Output
(8)
I
SOURCE
I
BAT
= 50mA
I
BAT
= 1.2A, T
J
= –40°C to +85°C
October 2007
3
M9999-102507
Micrel, Inc.
Notes:
1.
2.
3.
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
MIC79110
Dropout Voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V
differential. For outputs below 2.5V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 2.5V. Minimum input
operating voltage is 2.5V.
V
NOM
denotes the nominal output voltage.
IR
SET
= (0.2V/R
SET
) × 1000
Output Current I
EOC
when Digital End-of-Charge output goes high impedance. Currents greater than I
EOC
, the D
EOC
output is low, currents lower
than I
EOC
, D
EOC
is high impedance.
I
EOC
= (0.2V/R
EOC
) × 1000
I
SOURCE
is the current output from A
CHG
pin. A resistor to ground from the A
CHG
pin will program a voltage that is proportional to the output current.
4.
5.
6.
7.
8.
Block Diagram
V
IN
Current
Limit Sense
Thermal
Protection
+
V
REF
End of
Charge
Detect
BAT
SNS
Li-Ion
D
EOC
SD
Shutdown
Control
R
SET
Current
Limit Set
A
CHG
R
EOC
GND
MIC79110 Block Diagram
October 2007
4
M9999-102507
Micrel, Inc.
MIC79110
Typical Characteristics
October 2007
5
M9999-102507
Microcontroller MCU
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