LM3420-4.2, -8.2, -8.4, -12.6, -16.8 Lithium-Ion Battery Charge Controller
July 2000
LM3420-4.2, -8.2, -8.4, -12.6, -16.8
Lithium-Ion Battery Charge Controller
General Description
The LM3420 series of controllers are monolithic integrated
circuits designed for charging and end-of-charge control for
Lithium-Ion rechargeable batteries. The LM3420 is available
in five fixed voltage versions for one through four cell charger
applications (4.2V, 8.2V/8.4V, 12.6V and 16.8V respec-
tively).
Included in a very small package is an (internally compen-
sated) op amp, a bandgap reference, an NPN output tran-
sistor, and voltage setting resistors. The amplifier’s inverting
input is externally accessible for loop frequency compensa-
tion. The output is an open-emitter NPN transistor capable of
driving up to 15 mA of output current into external circuitry.
A trimmed precision bandgap reference utilizes temperature
drift curvature correction for excellent voltage stability over
the operating temperature range. Available with an initial
tolerance of 0.5% for the A grade version, and 1% for the
standard version, the LM3420 allows for precision end-of-
charge control for Lithium-Ion rechargeable batteries.
The LM3420 is available in a sub-miniature 5-lead SOT23-5
surface mount package thus allowing very compact designs.
Features
n
n
n
n
n
Voltage options for charging 1, 2, 3 or 4 cells
Tiny SOT23-5 package
Precision (0.5%) end-of-charge control
Drive capability for external power stage
Low quiescent current, 85 µA (typ.)
Applications
n
Lithium-Ion battery charging
n
Suitable for linear and switching regulator charger
designs
Typical Application and Functional Diagram
01235901
Typical Constant Current/Constant Voltage
Li-Ion Battery Charger
01235902
LM3420 Functional Diagram
SIMPLE SWITCHER
®
is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation
DS012359
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LM3420-4.2/LM3420-8.2/LM3420-8.4/LM3420-12.6/LM3420-16.8
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Input Voltage V(IN)
Output Current
Junction Temperature
Storage Temperature
Lead Temperature
Vapor Phase (60 seconds)
Infrared (15 seconds)
Power Dissipation (T
A
= 25˚C)
(Note 2)
+215˚C
+220˚C
300 mW
20V
20 mA
150˚C
−65˚C to +150˚C
ESD Susceptibility (Note 3)
Human Body Model
1500V
See AN-450 “Surface Mounting Methods and Their Effect
on Product Reliability” for methods on soldering
surface-mount devices.
Operating Ratings
(Notes 1, 2)
Ambient Temperature Range
Junction Temperature Range
Output Current
−40˚C
≤
T
A
≤
+85˚C
−40˚C
≤
T
J
≤
+125˚C
15 mA
LM3420-4.2
Electrical Characteristics
Specifications with standard type face are for T
J
= 25˚C, and those with
boldface type
apply over
full Operating Tempera-
ture Range.
Unless otherwise specified, V(IN) = V
REG
, V
OUT
= 1.5V.
Symbol
Parameter
Conditions
Typical
(Note 4)
V
REG
Regulation Voltage
I
OUT
= 1 mA
4.2
4.221/4.242
4.179/4.158
Regulation Voltage
Tolerance
I
q
G
m
Quiescent Current
Transconductance
∆I
OUT
/∆V
REG
I
OUT
= 1 mA
20 µA
≤
I
OUT
≤
1 mA
V
OUT
= 2V
1 mA
≤
I
OUT
≤
15 mA
V
OUT
= 2V
A
V
Voltage Gain
∆V
OUT
/∆V
REG
1V
≤
V
OUT
≤
V
REG
− 1.2V
(−1.3)
R
L
= 200Ω (Note 6)
1V
≤
V
OUT
≤
V
REG
− 1.2V
(−1.3)
R
L
= 2 kΩ
V
SAT
I
L
R
f
Output Saturation
(Note 7)
Output Leakage
Current
Internal Feedback
Resistor (Note 8)
E
n
Output Noise
Voltage
I
OUT
= 1 mA, 10 Hz
≤
f
≤
10 kHz
70
V(IN) = V
REG
+100 mV
I
OUT
= 15 mA
V(IN) = V
REG
−100 mV
V
OUT
= 0V
75
94
56
94
56
0.1
0.5/1.0
0.5/1.0
1.0
1.2/1.3
1.2/1.3
3500
1500/900
1000/700
1000
550/250
450/200
6.0
3.0/1.5
2.5/1.4
85
110/115
3.3
1.3/0.75
1.0/0.50
125/150
µA
µA(max)
mA/mV
mA/mV(min)
mA/mV
mA/mV(min)
V/V
V/V(min)
V/V
V/V(min)
V
V(max)
µA
µA(max)
kΩ
kΩ(max)
kΩ(min)
µV
RMS
I
OUT
= 1 mA
4.242/4.284
4.158/4.116
LM3420A-4.2
Limit
(Note 5)
LM3420-4.2
Limit
(Note 5)
V
V(max)
V(min)
%(max)
Units
(Limits)
±
0.5/
±
1
±
1/
±
2
3
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LM3420-4.2/LM3420-8.2/LM3420-8.4/LM3420-12.6/LM3420-16.8
LM3420-8.2
Electrical Characteristics
Specifications with standard type face are for T
J
= 25˚C, and those with
boldface type
apply over
full Operating Tempera-
ture Range.
Unless otherwise specified, V(IN) = V
REG
, V
OUT
= 1.5V.
Symbol
Parameter
Conditions
Typical
(Note 4)
V
REG
Regulation Voltage
I
OUT
= 1 mA
8.2
8.241/8.282
8.159/8.118
Regulation Voltage
Tolerance
I
q
G
m
Quiescent Current
Transconductance
∆I
OUT
/∆V
REG
I
OUT
= 1 mA
20 µA
≤
I
OUT
≤
1 mA
V
OUT
= 6V
1 mA
≤
I
OUT
≤
15 mA
V
OUT
= 6V
A
V
Voltage Gain
∆V
OUT
/∆V
REG
1V
≤
V
OUT
≤
V
REG
− 1.2V
(−1.3)
R
L
= 470Ω (Note 6)
1V
≤
V
OUT
≤
V
REG
− 1.2V
(−1.3)
R
L
= 5 kΩ
V
SAT
I
L
R
f
Output Saturation
(Note 7)
Output Leakage
Current
Internal Feedback
Resistor (Note 8)
E
n
Output Noise
Voltage
I
OUT
= 1 mA, 10 Hz
≤
f
≤
10 kHz
140
V(IN) = V
REG
+100 mV
I
OUT
= 15 mA
V(IN) = V
REG
−100 mV
V
OUT
= 0V
176
220
132
220
132
0.1
0.5/1.0
0.5/1.0
1.0
1.2/1.3
1.2/1.3
3500
1500/900
1000/700
1000
550/250
450/200
6.0
3.0/1.5
2.5/1.4
85
110/115
3.3
1.3/0.75
1.0/0.50
125/150
µA
µA(max)
mA/mV
mA/mV(min)
mA/mV
mA/mV(min)
V/V
V/V(min)
V/V
V/V(min)
V
V(max)
µA
µA(max)
kΩ
kΩ(max)
kΩ(min)
µV
RMS
I
OUT
= 1 mA
8.282/8.364
8.118/8.036
LM3420A-8.2
Limit
(Note 5)
LM3420-8.2
Limit
(Note 5)
V
V(max)
V(min)
%(max)
Units
(Limits)
±
0.5/
±
1
±
1/
±
2
LM3420-8.4
Electrical Characteristics
Specifications with standard type face are for T
J
= 25˚C, and those with
boldface type
apply over
full Operating Tempera-
ture Range.
Unless otherwise specified, V(IN) = V
REG
, V
OUT
= 1.5V.
Symbol
Parameter
Conditions
Typical
(Note 4)
V
REG
Regulation Voltage
I
OUT
= 1 mA
8.4
8.442/8.484
8.358/8.316
Regulation Voltage
Tolerance
I
q
G
m
Quiescent Current
Transconductance
∆I
OUT
/∆V
REG
I
OUT
= 1 mA
20 µA
≤
I
OUT
≤
1 mA
V
OUT
= 6V
1 mA
≤
I
OUT
≤
15 mA
V
OUT
= 6V
6.0
3.0/1.5
2.5/1.4
85
110/115
3.3
1.3/0.75
1.0/0.50
125/150
µA
µA(max)
mA/mV
mA/mV(min)
mA/mV
mA/mV(min)
I
OUT
= 1 mA
8.484/8.568
8.316/8.232
LM3420A-8.4
Limit
(Note 5)
LM3420-8.4
Limit
(Note 5)
V
V(max)
V(min)
%(max)
Units
(Limits)
±
0.5/
±
1
±
1/
±
2
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