LM3620
Lithium-Ion Battery Charger Controller
General Description
The LM3620 series of controllers are monolithic integrated
circuits designed to control the charging and end-of-charge
control for lithium-ion rechargeable batteries. The LM3620 is
available in two versions for one or two cell charger applica-
tions. Each version provides the option of selecting the ap-
propriate termination voltage for either coke or graphite an-
ode lithium cells.
The LM3620 can operate from a wide range of DC input
sources (4V to 30V). With no charger supply connected, the
controller draws a quiescent current of only 10nA to minimize
discharging of a connected battery pack.
The LM3620 consists of an operational transconductance
amplifier, a bandgap voltage reference, a NPN driver transis-
tor and precision voltage setting resistors. The output of the
amplifier is made available to drive an external power tran-
sistor if higher drive currents are required.
With a trimmed output voltage regulation of
1.2% initial ac-
curacy, the LM3620 provides a simple, precise solution for
end-of-charge control of lithium-ion rechargeable cells.
The LM3620 is packaged in a miniature 5-lead SOT-23 sur-
face mount package for very compact designs.
Features
n
Voltage options for charging 1 or 2 cell stacks
n
Adjustable output voltage for coke or graphite anodes
n
Precision end-of-charge voltage control
n
Wide input voltage range (4V to 30V)
n
Low off state current (
<
10nA)
n
Drive provided for external power stage
n
Tiny SOT-23 package
Typical Application
DS100841-10
July 2000
LM3620
Lithium-Ion
Battery
Charger
Controller
2000 National Semiconductor Corporation
DS100841
www.national.com
Connection Diagram
Ordering Information
Device Order
Number
Package
Marking
Output
Voltage
Initial
Accuracy
(25C)
Over
Temperature
Accuracy
(0 to 70C)
Number
of Cells
Supplied as
LM3620M5-4
D10B
4.1V/4.2V
1.2%
2%
1
1000 Unit increments on Tape and
Reel
LM3620M5X-4
D10B
4.1V/4.2V
1.2%
2%
1
3000 Unit increments on Tape and
Reel
LM3620M5-8
D11B
8.2V/8.4V
1.2%
2%
2
1000 Unit increments on Tape and
Reel
LM3620M5X-8
D11B
8.2V/8.4V
1.2%
2%
2
3000 Unit increments on Tape and
Reel
The small physical size of the SOT23-5 Package does not allow for the full part number marking. Devices will be marked with the
designation shown in the column Package Marking.
The devices are shipped in tape-and-reel format. The standard quantity is 250 units on a reel (indicated by the letters "M5" in the
part number), or 3000 units on a reel (indicated by the letters "M5X" in the part number).
5-Lead SOT23-5 Surface Mount Package
DS100841-1
Refer to the Ordering Information Table in
this Data Sheet for Specific Part Number
See NS Package MF05A
LM3620
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2
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
DRIVE
)
35V
V
EXT
1.5V
Junction Temperature
150C
Storage Temperature
-65 to +150C
Lead Temp. Soldering
Vapor Phase (60 sec.)
Infrared (15 sec.)
215C
220C
Power Dissipation (T
A
= 25C)
(Note 2)
300mW
ESD Susceptibility (Note 3)
2000V
Operating Ratings
(Note 1)
Ambient Temp. Range
0C to 70C
Junction Temp. Range
0C to 125C
Thermal Resistance (Junction to
Ambient,
J-A
)
280C/W
Input Voltage (V
DRIVE
)
4V to 30V
Electrical Characteristics
LM3620-4
V
DRIVE
= 5V, I
DRIVE
= 2mA. Limits with boldface type apply over the full operating ambient temperature range, 0C to +70C,
limits with standard typeface apply for T
A
= 25C.
Symbol
Parameter
Conditions
Typical
Limit
Units
V
REG
Regulated Output Voltage (pin
1 to ground)
Pin 5 shorted to pin 1 (graphite
anode)
4.1
4.051/4.018
V(min)
4.149/4.182
V(max)
Pin 5 open (coke anode)
4.2
4.150/4.116
V(min)
4.250/4.284
V(max)
Regulated Output Voltage
Tolerance
Either Pin 5 setting
1.2/
2.0
%
V
REG
/V
DRIVE
Supply Sensitivity
V
REG
for 5V
V
DRIVE
30V
100
V/V(max)
I
Q
Quiescent Current
V
REG
= 4.5V, V
EXT
= 1.0V (Note 4)
400
750
A(max)
I
OFF
Off State Current
V
DRIVE
open circuited (Note 5)
10
200
nA(max)
I
DRIVE
Drive Pin Sink Current
V
DRIVE
= 5.0V
20
15
mA(min)
Gm
(DRIVE)
Drive Pin Transconductance
I
DRIVE
/
V
REG
2mA
I
DRIVE
15mA
3
A/V
I
EXT
External Pin Source Current
V
EXT
= 1V (Note 6)
3
2.5
mA(min)
Gm
(EXT)
External Pin Transconductance
I
EXT
/
V
REG
, V
EXT
= 1V
0mA
I
EXT
2.5mA
0.8
A/V
R
IN
V
REG
Input Resistance
Pin 1 to Ground.
Circuit biased with V
DRIVE
applied
V
DRIVE
open circuited
46
k
42
M
R
F
Feedback Resistance
Pin 1 to Pin 5
1500
LM3620
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3
LM3620-8
V
DRIVE
= 5V, I
DRIVE
= 2mA. Limits with boldface type apply over the full operating ambient temperature range, 0C to + 70C,
limits with standard typeface apply for T
A
= 25C.
Symbol
Parameter
Conditions
Typical
Limit
Units
V
REG
Regulated Output Voltage (pin
1 to ground)
Pin 5 shorted to pin 1 (graphite
anode)
8.2
8.102/8.036
V(min)
8.298/8.364
V(max)
Pin 5 open (coke anode)
8.4
8.299/8.232
V(min)
8.501/8.568
V(max)
Regulated Output Voltage
Tolerance
Either Pin 5 setting
1.2/
2.0
%
V
REG
/V
DRIVE
Supply Sensitivity
V
REG
for 5V
V
DRIVE
30V
200
V/V(max)
I
Q
Quiescent Current
V
REG
= 8.7V, V
EXT
= 1.0V (Note 4)
400
750
A(max)
I
OFF
Off State Current
V
DRIVE
open circuited (Note 5)
10
200
nA(max)
I
DRIVE
Drive Pin Sink Current
V
DRIVE
= 5.0V
20
15
mA(min)
Gm
(DRIVE)
Drive Pin Transconductance
I
DRIVE
/
V
REG
2mA
I
DRIVE
15mA
1.5
A/V
I
EXT
External Pin Source Current
V
EXT
= 1V (Note 6)
3
2.5
mA(min)
Gm
(EXT)
External Pin Transconductance
I
EXT
/
V
REG
, V
EXT
= 1V
0mA
I
EXT
2.5mA
0.4
A/V
R
IN
V
REG
Input Resistance
Pin 1 to Ground.
Circuit biased with V
DRIVE
applied
V
DRIVE
open circuited
110
k
42
M
R
F
Feedback Resistance
Pin 1 to Pin 5
2900
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is in-
tended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.
Note 2: The maximum power dissipation must be derated at elevated temperatures and is limited by T
JMAX
(maximum junction temperature),
J-A
(junction-to-ambient thermal resistance) and T
A
(ambient temperature). The maximum power dissipation at any temperature is: PDiss
MAX
= (T
JMAX
- T
A
)/
J-A
up to
the value listed in the Absolute Maximum Ratings.
Note 3: Rating is for the human body model, a 100 pF capacitor discharged through a 1.5k
resistor into each pin.
Note 4: Quiescent current is all current flowing to ground when the voltage at the V
REG
pin is forced to be above the nominal regulating voltage (V
REG
).
Note 5: Off current is all of the current flowing to ground including all leakage current that would be drawn from the battery connected to the V
REG
terminal.
Note 6: When the External pin is being used as the driving source, it is recommended to keep the operating point of V
EXT
1V. If greater than 1V, the internal circuitry
would bias I
DRIVE
to conduct up to the current limit level continuously causing unnecessary power dissipation in the device.
LM3620
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4
Typical Performance Characteristics
Unless otherwise specified, T
A
= 25C.
LM3620M5-4
Normalized Regulation Voltage
Change vs I
DRIVE
DS100841-4
LM3620M5-4
Normalized Regulation Voltage
Change vs V
DRIVE
DS100841-8
LM3620M5-4
Normalized Regulation Voltage
Change vs I
EXT
DS100841-7
LM3620M5-4
Quiescent Current
vs V
DRIVE
DS100841-5
LM3620M5-4
Off State Current vs V
DRIVE
DS100841-6
LM3620M5-4
Off State Current
vs Temperature
DS100841-3
LM3620M5-4
Bode Plot (
V
DRIVE
/
V
REG
)
DS100841-9
LM3620
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5
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