MIC79050
Micrel, Inc.
MIC79050
Simple Lithium-Ion Battery Charger
General Description
The MIC79050 is a simple single-cell lithium-ion battery char-
ger. It includes an on-chip pass transistor for high precision
charging. Featuring ultrahigh precision (+0.75% over the Li-
ion battery charging temperature range) and “zero” off mode
current, the MIC79050 provides a very simple, cost effective
solution for charging lithium-ion battery.
Other features of the MIC79050 include current limit and
thermal shutdown protection. In the event the input voltage
to the charger is disconnected, the MIC79050 also provides
minimal reverse-current and reversed-battery protection.
The MIC79050 is a fixed 4.2V device and comes in the ther-
mally-enhanced MSO-8, SO-8, and SOT-223 packages. The
8-pin versions also come equipped with enable and feedback
inputs. All versions are specified over the temperature range
of –40°C to +125°C.
Features
• High accuracy charge voltage:
±0.75% over -5°C to + 60°C (Li-ion charging
temperature range)
• “Zero” off-mode current
• 10µA reverse leakage
• Ultralow 380mV dropout at 500mA
• Wide input voltage range
• Logic controlled enable input (8-pin devices only)
• Thermal shutdown and current limit protection
• Power MSOP-8, Power SOIC-8, and SOT-223
• Pulse charging capability
Applications
•
•
•
•
•
Li-ion battery charger
Celluar phones
Palmtop computers
PDAs
Self charging battery packs
Ordering Information
Part Number
Standard
MIC79050-4.2BS
MIC79050-4.2BM
MIC79050-4.2BMM
Pb-Free
MIC79050-4.2YS
MIC79050-4.2YM
MIC79050-4.2YMM
Voltage
4.2V
4.2V
4.2V
Junction
Temp. Range
–40ºC to +125ºC
–40ºC to +125ºC
–40ºC to +125ºC
Package
SOT-223-3
SOIC-8
MSOP-8
Typical Applications
Regulated or
unregulated
wall adapter
MIC79050-4.2BS
IN
BAT
GND
4.2V 0.75% Over Temp
Li-Ion
Cell
Simplest Battery Charging Solution
Regulated or
unregulated
wall adapter
MIC79050-4.2BMM
IN
BAT
EN
FB
GND
4.2V 0.75%
Li-Ion
Cell
External PWM*
*See Applications Information
Pulse-Charging Application
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
August 2005
1
MIC79050
MIC79050
Micrel, Inc.
Pin Configuration
GND
TAB
1
2
3
IN
GND BAT
MIC79050-x.xBS/YS
SOT-223
EN 1
IN 2
BAT 3
FB 4
GND
GND
GND
GND
8
7
6
5
MIC79050-x.xBM/YM
SOIC-8 and MSOP-8
Pin Description
Pin No.
SOT-223
1
2,
TAB
3
Pin No.
SOIC-8
MSOP-8
2
5–8
3
1
4
Pin Name
Pin Function
IN
GND
BAT
EN
FB
Supply Input
Ground: SOT-223 pin 2 and
TAB
are internally connected. SO-8 pins 5 through 8 are
internally connected.
Battery Voltage Output
Enable (Input): TTL/CMOS compatible control input. Logic high = enable; logic low or open =
shutdown.
Feedback Node
MIC79050
2
August 2005
MIC79050
Micrel, Inc.
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage (V
IN
) ..............................–20V to +20V
Power Dissipation (P
D
) ................ Internally Limited,
Note 3
Junction Temperature (T
J
) ........................ –40°C to +125°C
Lead Temperature (soldering, 5 sec.) ........................ 260°C
Storage Temperature (T
S
) ........................ –65°C to +150°C
Operating Ratings
(Note 2)
Supply Input Voltage (V
IN
) ............................ +2.5V to +16V
Enable Input Voltage (V
EN
) ...................................0V to V
IN
Junction Temperature (T
J
) ........................ –40°C to +125°C
Package Thermal Resistance (Note 3)................................
MSOP-8 (θ
JA
) ...................................................... 80°C/W
SOIC-8(θ
JA
) ......................................................... 63°C/W
SOT-223(θ
JC
) ...................................................... 15°C/W
Electrical Characteristics
Symbol
V
BAT
Parameter
Conditions
Note 4
Battery Voltage Accuracy
Battery Voltage
Temperature Coefficient
Line Regulation
Load Regulation
Dropout Voltage,
Note 6
Ground Pin Current,
Notes 7, 8
V
IN
= V
BAT
+ 1.0V; C
OUT
= 4.7µF, I
OUT
= 100µA; T
J
= 25°C,
bold
values indicate –40°C ≤ T
J
≤ +125°C; unless noted.
Min
variation from nominal V
OUT
–5°C to +60°C
–0.75
40
Typical
Max
+0.75
Units
%
ΔV
BAT
/ΔT
ppm/°C
ΔV
BAT
/V
BAT
ΔV
BAT
/V
BAT
V
IN
– V
BAT
I
GND
V
IN
= V
BAT
+ 1V to 16V
I
OUT
= 100µA to 500mA,
Note 5
I
OUT
= 500mA
V
EN
≥ 3.0V, I
OUT
= 100µA
V
EN
≥ 3.0V, I
OUT
= 500mA
0.009
0.05
380
85
11
0.05
0.10
75
750
0.05
0.4
2.0
0.01
0.01
5
0.05
0.1
0.5
0.7
500
600
130
170
20
25
3
8
900
1000
%/V
%/V
%
%
mV
mV
µA
µA
mA
mA
µA
µA
dB
mA
mA
%/W
V
V
V
µA
µA
µA
µA
I
GND
PSRR
I
LIMIT
ΔV
BAT
/ΔP
D
V
ENL
Ground Pin Quiescent Current,
Note 8
Ripple Rejection
Current Limit
Thermal Regulation
Enable Input Logic-Low Voltage
V
EN
≤ 0.4V (shutdown)
f = 120Hz
V
EN
≤ 0.18V (shutdown)
V
BAT
= 0V
Note 9
ENABLE Input
V
EN
= logic low (shutdown)
V
EN
= logic high (enabled)
V
ENL
≤ 0.18V (shutdown)
0.18
–1
–2
20
25
I
ENL
I
ENH
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
Note 6.
Note 7:
Note 8:
Note 9:
Enable Input Current
V
ENL
≤ 0.4V (shutdown)
V
ENH
≥ 2.0V (enabled)
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
The maximum allowable power dissipation at any T
A
(ambient temperature) is calculated using: P
D(max)
= (T
J(max)
– T
A
)
÷ θ
JA
. Exceeding the
maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
Battery voltage temperature coefficient is the worst case voltage change divided by the total temperature range.
Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load
range from 100µA to 500mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
Dropout voltage is defined as the input to battery output differential at which the battery voltage drops 2% below its nominal value measured at
1V differential.
Ground pin current is the charger quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of the
load current plus the ground pin current.
V
EN
is the voltage externally applied to devices with the EN (enable) input pin. [MSO-8(MM) and SO-8 (M) packages only.]
Thermal regulation is the change in battery voltage at a time “t” after a change in power dissipation is applied, excluding load or line regulation
effects. Specifications are for a 500mA load pulse at V
IN
= 16V for t = 10ms.
August 2005
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MIC79050
MIC79050
Micrel, Inc.
Typical Characteristics
Dropout Voltage
vs. Output Current
Dropout Voltage
vs. Temperature
Dropout Characteristics
5
OUTPUT VOLTAGE (V)
4
3
2
1
0
0
400
DROPOUT VOLTAGE (mV)
300
200
100
0
0
600
DROPOUT VOLTAGE (mV)
500
400
300
200
100
0
-40
100 200 300 400 500
OUTPUT CURRENT (mA)
0
40
80
TEMPERATURE (°C)
120
5mA
50mA,150mA
2 4 6 8 10 12 14 16
INPUT VOLTAGE (V)
Dropout Characteristics
5
OUTPUT VOLTAGE (V)
4
3
2
1
0
0
2
4
INPUT VOLTAGE (V)
6
12
GROUND CURRENT (mA)
10
8
6
4
2
0
0
Output Current
vs. Ground
1.5
GROUND CURRENT (mA)
Ground Current
vs. Supply Voltage
50mA
250mA
500mA
1
5mA
0.5
100 200 300 400 500
OUTPUT CURRENT (mA)
0
0
12
4
8
SUPPLY VOLTAGE (V)
16
25
GROUND CURRENT (mA)
20
15
10
5
0
0
Ground Current
vs. Supply Voltage
500mA
150
GROUND CURRENT (µA)
Ground Current
vs. Temperature
4.0
GROUND CURRENT (mA)
3.8
3.6
3.4
3.2
3.0
-40
Ground Current
vs. Temperature
100
250mA
125mA
50
1
2
3
4
5
SUPPLY VOLTAGE (V)
6
0
-40
0
40
80
TEMPERATURE (°C)
120
0
40
80
TEMPERATURE (°C)
120
13.0
12.5
12.0
11.5
11.0
-40
0
40
80
TEMPERATURE (°C)
120
4.205
4.200
4.195
4.190
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
SHORT CIRCUIT CURRENT (mA)
13.5
GROUND CURRENT (mA)
Ground Current
vs. Temperature
4.210
OUTPUT VOLTAGE (V)
Battery Voltage
vs. Temperature
800
700
600
500
400
300
200
100
0
-40
Short Circuit Current
vs. Temperature
0
40
80
TEMPERATURE (°C)
120
MIC79050
4
August 2005
MIC79050
Micrel, Inc.
DRIFT FROM NOMINAL VOUT (%)
0.75
REVERSE LEAKAGE CURRENT (µA)
20
15
10
5
0
0
REVERSE LEAKAGE CURRENT (µA)
Typical Voltage Drift Limits
vs. Time
Reverse Leakage Current
vs. Output Voltage
20
15
Reverse Leakage Current
vs. Output Voltage
4.2V
3.6V
0.25
Upper
-0.25
Lower
10
3.0V
5
0
-5
-0.75
0
200
400
600
TIME (hrs)
800
1
2
3
4
OUTPUT VOLTAGE (V)
5
V
IN
+V
E N
FLOATING
5
15 25 35 45 55
TEMPERATURE (°C)
REVERSE LEAKAGE CURRENT (uA)
20
15
Reverse Leakage Current
vs. Temperature
4.2V
3.6V
10
3.0V
5
0
-5
5
GROUNDED
15 25 35 45 55
TEMPERATURE (°C)
V
IN
+V
E N
August 2005
5
MIC79050
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