MAX1811.pdf

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19-2024; Rev 2; 6/03
USB-Powered Li+ Charger
General Description
The MAX1811 is a single-cell lithium-ion (Li+) battery
charger that can be powered directly from a USB port*
or from an external supply up to 6.5V. It has a 0.5%
overall battery regulation voltage accuracy to allow
maximum utilization of the battery capacity.
The charger uses an internal FET to deliver up to
500mA charging current to the battery. The device can
be configured for either a 4.1V or 4.2V battery, using
the SELV input. The SELI input sets the charge current
to either 100mA or 500mA. An open-drain output (CHG)
indicates charge status.
The MAX1811 has preconditioning that soft-starts a
near-dead battery cell before charging. Other safety
features include continuous monitoring of voltage and
current and initial checking for fault conditions before
charging.
The MAX1811 is available in a small 1.4W thermally
enhanced 8-pin SO package.
Features
o
Charges Single-Cell Li+ Batteries Directly from
USB Port
o
0.5% Overall Charging Accuracy
o
Minimal External Components
o
Input Diode Not Required
o
Automatic IC Thermal Regulation
o
Preconditions Near-Depleted Cells
o
Convenient Power SO-8 Package (1.4W)
o
Protected by U.S. Patent # 6,507,172
MAX1811
________________________Applications
PDAs and Palmtops
Digital Still Cameras
MP3 Players
Cell Phones
Two-Way Pagers
Hand-Held Computers
PART
MAX1811ESA
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
8 SO
Typical Operating Circuit
TO LOAD
SINGLE
Li+
CELL
TO IN
LED
GND
CHG
SELI
GND
CHG
LOGIC OUT
3
Pin Configuration
TOP VIEW
BATT
4.35V TO 6.5V
4.2V
4.1V
ON
OFF
500mA
100mA
EN
SELV
IN
SELV
SELI
1
2
8
7
CHG
EN
GND
BATT
MAX1811
MAX1811
6
5
IN
4
SO
*
Protected by U.S. Patent # 6,507,172
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
USB-Powered Li+ Charger
MAX1811
ABSOLUTE MAXIMUM RATINGS
IN, BATT, SELI,
CHG,
EN to GND ..............................-0.3V to 7V
SELV to GND ...............................................-0.3V to (V
IN
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 17.5mW/°C above +70°C)....................1.4W
Short-Circuit Duration.................................................Continuous
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Maximum Die Temperature..............................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
IN
= 4.5V, EN = IN,
T
A
= 0°C to +85°C,
unless otherwise noted.)
PARAMETER
Input Supply Voltage
Input Undervoltage Lockout
Input Undervoltage Lockout Hysteresis
Input Supply Current
Operating, EN = IN, no load
Shutdown, EN = GND
SELI = GND (100mA mode),
V
IN
= 4.35V
SELI = IN (500mA mode)
BATT rising, transition from precondition to
charge mode
V
IN
= V
CHG
= 6.5V
I
SINK
= 10mA
V
SELI
= V
IN
= 5.5V, V
BATT
= 2.7V
SELI = GND, V
IN
= 5.5V, V
BATT
= 2.7V
V
BATT
= 2V, SELI = GND or IN
SELV = GND, I
BATT
= 0
SELV = IN, I
BATT
= 0
V
BATT
= 4.2V, EN = IN = GND
EN = GND, V
BATT
= 4.2V
V
IN
= 4.35V to 6.5V
V
IN
= 4.35V to 6.5V
V
IN
= 0 to 6.5V; V
SELI
, V
EN
= 6.5V or GND
V
IN
= 0 to 6.5V, V
SELV
= V
IN
or GND
Die temperature beyond which charging
current is reduced
125
2.0
1
1
2.3
I
IN
rising
CONDITIONS
MIN
4.35
3.75
50
0.9
2.5
100
200
2.5
80
0.1
455
85
43
4.10
4.20
1
0.1
1.0
0.4
500
100
70
4.12
4.22
5
2
0.8
2.7
V
mV
µA
V
mA
2.0
5.0
TYP
MAX
6.50
4.05
UNITS
V
V
mV
mA
µA
mV
Charging Headroom
Precondition Threshold
Precondition Threshold Hysteresis
CHG
Output Leakage Current
CHG
Output Low Voltage
Charging Current
BATT Regulation Voltage
BATT Leakage Current (Input
Power Removed)
BATT Shutdown Current
Logic Input Low Voltage (EN, SELI, SELV)
Logic Input High Voltage (EN, SELI, SELV)
Logic Input Leakage Current (EN, SELI)
Logic Input Leakage Current (SELV)
Thermal Regulation
20
4.08
4.18
V
µA
µA
V
V
µA
µA
°C
2
_______________________________________________________________________________________
USB-Powered Li+ Charger
ELECTRICAL CHARACTERISTICS
(V
IN
= 4.5V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note1)
PARAMETER
Input Supply Voltage
Input Undervoltage Lockout
Input Supply Current
Precondition Threshold
BATT Regulation Voltage
BATT Leakage Current (Input
Power Removed)
BATT Shutdown Current
I
IN
rising
Operating, EN = IN, no load
Shutdown, EN = GND
BATT rising, transition from precondition to
charge mode
SELV = GND, I
BATT
= 0
SELV = IN, I
BATT
= 0
V
BATT
= 4.2V, IN = GND
EN = GND, V
BATT
= 4.2V
2.3
4.06
4.16
CONDITIONS
MIN
4.35
3.75
TYP
MAX
6.50
4.05
3
6
2.7
4.14
4.24
10
3
UNITS
V
V
mA
µA
V
V
µA
µA
MAX1811
Note 1:
Specifications to -40°C are guaranteed by design and not production tested.
Typical Operating Characteristics
(CHG unconnected, C
BATT
= 2.2µF, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. INPUT VOLTAGE (ENABLED)
0.9
0.8
0.7
I
IN
(mA)
I
IN
(µA)
0.6
0.5
0.4
0.3
0.2
0.1
0
0
1
2
3
4
5
6
7
V
IN
(V)
V
SELI
= V
IN
V
SELI
= 0
V
IN
= V
EN
= V
SELV
MAX1811 toc01
SUPPLY CURRENT vs. INPUT VOLTAGE
(SHUTDOWN)
MAX1811 toc02
CHARGE CURRENT
vs. INPUT VOLTAGE HEADROOM
450
400
350
I
BATT
(mA)
300
250
200
150
100
50
0
V
SELI
= 0
V
BATT
= 4.1V
V
SELV
= V
IN
V
SELI
= V
IN
MAX1811 toc03
1.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
1
2
3
4
5
6
7
V
IN
(V)
V
IN
= V
SELV
V
EN
= 0
500
0
0.5
1.0
1.5
2.0
2.5
3.0
V
IN
- V
BATT
(V)
_______________________________________________________________________________________
3
USB-Powered Li+ Charger
MAX1811
Typical Operating Characteristics (continued)
(CHG unconnected, C
BATT
= 2.2µF, T
A
= +25°C, unless otherwise noted.)
CHARGE CURRENT
vs. BATTERY CURRENT
MAX1811 toc04
CHARGE CURENT
vs. INPUT VOLTAGE
MAX1811 toc05
BATTERY REGULATION VOLTAGE
vs. TEMPERATURE
MAX1811 toc06
500
450
400
350
I
BATT
(mA)
300
250
200
150
100
50
0
-50
0
V
SELI
= 0
V
SELI
= V
IN
V
IN
= V
EN
= V
SELV
= 5.5V
500
450
400
350
I
BATT
(mA)
V
BATT
= 4.1V
V
SELV
= V
IN
4.22
4.20
4.18
V
BATT
(V)
V
SELV
= V
IN
300
250
200
150
100
50
0
V
SELI
= V
IN
V
SELI
= 0
4.16
4.14
4.12
4.10
4.08
V
IN
= V
SELI
= V
EN
= 4.5V
I
BATT
= 0
V
SELV
= 0
-40
-15
10
35
60
85
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
V
BATT
(V)
0
1
2
3
4
5
6
7
V
IN
(V)
TEMPERATURE (°C)
CHARGE CURRENT
vs. TEMPERATURE
MAX1811 toc07
CHARGE CURRENT vs. TEMPERATURE
WITH THERMAL REGULATION
V
IN
= V
SELV
= V
EN
= 6.5V, V
BATT
= 2.7V
MAX1811 toc08
600
500
400
I
BATT
(mA)
300
200
100
0
-40
V
IN
= V
SELV
= V
EN
= 5.5V, V
BATT
= 2.7V
600
500
V
SELI
= V
IN
I
BATT
(mA)
V
SELI
= V
IN
400
300
200
THERMAL CONTROL
LOOP IN OPERATION
V
SELI
= 0
100
0
V
SELI
= 0
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
USB-Powered Li+ Charger
MAX1811
Pin Description
PIN
1
NAME
SELV
DESCRIPTION
Battery Regulation Voltage-Select Input. A low (< 0.8V) selects a 4.1V battery regulation set point. A high
(> 2.0V) selects a 4.2V battery regulation set point.
Battery Regulation Current-Select Input. A low (< 0.8V) selects a 100mA maximum battery regulation
current. A high (> 2.0V) selects a 500mA maximum battery regulation current. SELI is not diode clamped
to IN, and the voltage at V
SELI
can exceed the voltage at V
IN
.
Ground. Connect pins 3 and 6 to a large copper trace for maximum power dissipation.
Input Supply Voltage. Bypass with a 4.7µF capacitor to GND.
Li+ Battery Connection. Bypass with a capacitor no less than 2.2µF to GND. High impedance in
shutdown.
Enable Input. A high (> 2.0V) enables the device. A low (< 0.8V) disables the device and places it into
shutdown mode. BATT is high impedance when disabled.
Charging Indicator Open-Drain Output.
CHG
pulls low while the device is in charge mode (2.5V
< V
BATT
< BATT Regulation Voltage).
SELI
IN
2
3, 6
4
5
7
8
SELI
GND
IN
BATT
EN
CHG
VOLTAGE
LOOP
CURRENT
SELECTOR
REGULATOR
THERMAL
LOOP
3V
BATT
CHG
EN
BIAS
OVERCURRENT
DETECTOR
VOLTAGE
SELECTOR
(2.5V, 4.2V)
BATTERY
OVERVOLTAGE
DETECTOR
4.7V
2V
MAX
DETECTOR
CIRCUIT
CURRENT
LOOP
MAX1811
CURRENT-
SENSE
CIRCUIT
SELV
GND
Figure 1. Functional Diagram
_______________________________________________________________________________________
5

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