MIC79050
Simple Lithium-Ion Battery Charger
Features
• High-Accuracy Charge Voltage: ±0.75% over
–5°C to + 60°C (Li-ion charging temperature
range)
• Zero Off-Mode Current
• 10 µA Reverse Leakage
• Ultra-Low 380 mV Dropout at 500 mA
• Wide Input Voltage Range
• Logic-Controlled Enable Input (8-Lead Devices
Only)
• Thermal Shutdown and Current-Limit Protection
• Power MSOP-8, Power SOIC-8, and SOT-223
Packages
• Pulse Charging Capability
General Description
The MIC79050 is a simple single-cell lithium-ion battery
charger. It includes an on-chip pass transistor for high
precision charging. Featuring ultra-high 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
thermally-enhanced MSOP-8, SOIC-8, and SOT-223
packages. The 8-lead versions also come equipped
with enable and feedback inputs. All versions are
specified over the temperature range of –40°C to
+125°C.
Applications
•
•
•
•
•
Li-Ion Battery Charger
Cellular Phones
Palmtop Computers
PDAs
Self-Charging Battery Packs
Package Types
MIC79050
3-Lead SOT-223 (S)
MIC79050
8-Lead SOIC/MSOP (M/MM)
GND
TAB
EN 1
IN 2
BAT 3
FB 4
8
7
6
5
GND
GND
GND
GND
1
2
3
IN
GND BAT
2017 Microchip Technology Inc.
DS20005771A-page 1
MIC79050
Typical Application Circuits
Simplest Battery Charging
Solution
Regulated or
unregulated
wall adapter
MIC79050-4.2YS
IN
BAT
GND
4.2V 0.75% over Temp
Li-Ion
Cell
Pulse-Charging
Application
Regulated or
unregulated
wall adapter
MIC79050-4.2YMM
IN
BAT
EN
FB
GND
4.2V 0.75%
Li-Ion
Cell
External PWM*
*See Applications Information
Functional Block Diagrams
3-Lead Version
V
IN
IN
V
BAT
Bandgap
Ref.
Current Limit
Thermal Shutdown
MIC79050-4.2YS
GND
8-Lead Version
V
IN
IN
FB
V
BAT
Bandgap
Ref.
V
R E F
EN
Current Limit
Thermal Shutdown
MIC79050-4.2YM/YMM
GND
DS20005771A-page 2
2017 Microchip Technology Inc.
MIC79050
1.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings †
Supply Input Voltage (V
IN
) .......................................................................................................................... –20V to +20V
Power Dissipation (P
D
) (Note
1)
............................................................................................................ Internally Limited
Operating Ratings ‡
Supply Input Voltage (V
IN
) ......................................................................................................................... +2.5V to +16V
Enable Input Voltage (V
EN
) .................................................................................................................................0V to V
IN
† Notice:
Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of the device at those or any other conditions above those indicated
in the operational sections of this specification is not intended. Exposure to maximum rating conditions for extended
periods may affect device reliability.
‡ Notice:
The device is not guaranteed to function outside its operating ratings.
Note 1:
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 tem-
perature, and the regulator will go into thermal shutdown.
TABLE 1-1:
ELECTRICAL CHARACTERISTICS
Electrical Characteristics:
V
IN
= V
BAT
+ 1.0V; C
OUT
= 4.7
μF,
I
OUT
= 100
μA;
T
J
= +25°C,
bold
values indicate
–40°C
≤
T
J
≤
+125°C; unless noted.
Parameter
Battery Voltage Accuracy
Battery Voltage Temperature
Coefficient
Line Regulation
Load Regulation
Dropout Voltage (Note
3)
Symbol
V
BAT
∆V
BAT
/
∆T
∆V
BAT
/
V
BAT
∆V
BAT
/
V
BAT
V
IN
–
V
BAT
Min.
–0.75
—
—
—
—
—
—
—
—
Ground Pin Current (Note
4,
Note 5)
Ground Pin Quiescent
Current (Note
5)
Ripple Rejection
Current Limit
Thermal Regulation
ENABLE Input
Enable Input Logic-Low
Voltage
—
V
ENL
—
2.0
0.4
—
—
—
0.18
—
V
V
EN
= logic-low (shutdown)
V
EN
= logic-high (enabled)
I
GND
—
—
—
I
GND
PSRR
I
LIMIT
∆V
BAT
/
∆P
D
—
—
—
—
—
—
Typ.
—
40
0.009
—
0.05
—
380
—
85
—
11
—
0.05
0.10
75
750
—
0.05
Max.
0.75
—
0.05
0.1
0.5
0.7
500
600
130
170
20
25
3
8
—
900
1000
—
Units
%
ppm/°C
%/V
%
mV
µA
mA
µA
dB
mA
%/W
Conditions
Variation from nominal V
OUT
, –5°C
to +60°C
Note 1
V
IN
= V
BAT
+ 1V to 16V
I
OUT
= 100
μA
to 500 mA,
Note 2
I
OUT
= 500 mA
V
EN
≥
3.0V, I
OUT
= 100
μA
V
EN
≥
3.0V, I
OUT
= 500 mA
V
EN
≤
0.4V (shutdown)
V
EN
≤
0.18V (shutdown)
f = 120 Hz
V
BAT
= 0V
Note 6
2017 Microchip Technology Inc.
DS20005771A-page 3
MIC79050
TABLE 1-1:
ELECTRICAL CHARACTERISTICS (CONTINUED)
Electrical Characteristics:
V
IN
= V
BAT
+ 1.0V; C
OUT
= 4.7
μF,
I
OUT
= 100
μA;
T
J
= +25°C,
bold
values indicate
–40°C
≤
T
J
≤
+125°C; unless noted.
Parameter
Enable Input Current
—
Note 1:
2:
Symbol
I
ENL
I
ENH
Min.
—
—
—
—
Typ.
0.01
0.01
5
—
Max.
–1
–2
20
25
Units
µA
µA
Conditions
V
ENL
≤
0.4V (shutdown)
V
ENL
≤
0.18V (shutdown)
V
ENH
≥
2.0V (enabled)
3:
4:
5:
6:
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 100
μA
to 500 mA. Changes in output voltage due to heat-
ing 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. MSOP-8 (MM) and SOIC-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 500 mA load pulse at V
IN
= 16V
for t = 10 ms.
DS20005771A-page 4
2017 Microchip Technology Inc.
MIC79050
TEMPERATURE SPECIFICATIONS (Note
1)
Parameters
Temperature Ranges
Junction Operating Temperature
Range
Storage Temperature Range
Lead Temperature
Package Thermal Resistances (Note
2)
Thermal Resistance MSOP-8
Thermal Resistance SOIC-8
Thermal Resistance SOT-223
Note 1:
JA
JA
JC
JA
—
—
—
—
80
63
15
62
—
—
—
—
°C/W
°C/W
°C/W
°C/W
—
—
—
—
T
J
T
S
—
–40
–65
—
—
—
—
+125
+150
+260
°C
°C
°C
—
—
Soldering, 5s
Sym.
Min.
Typ.
Max.
Units
Conditions
2:
The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable
junction temperature and the thermal resistance from junction to air (i.e., T
A
, T
J
,
JA
). Exceeding the
maximum allowable power dissipation will cause the device operating junction temperature to exceed the
maximum +125°C rating. Sustained junction temperatures above +125°C can impact the device reliability.
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 tem-
perature, and the regulator will go into thermal shutdown.
2017 Microchip Technology Inc.
DS20005771A-page 5
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