MAX1811 DS

MAX1811
USB-Powered Li+ Charger
LE
AVAILAB
General Description
Features
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.
♦ Charges Single-Cell Li+ Batteries Directly from
USB Port
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.
♦ P2
♦ 0.5% Overall Charging Accuracy
♦ Minimal External Components
♦ Input Diode Not Required
♦ Automatic IC Thermal Regulation
♦ Preconditions Near-Depleted Cells
♦ Convenient Power SO-8 Package (1.4W)
The MAX1811 is available in a small 1.4W thermally
enhanced 8-pin SO package.
________________________Applications
PDAs and Palmtops
Ordering Information
PART
Digital Still Cameras
MAX1811ESA
TEMP RANGE
PIN-PACKAGE
-40°C to +85°C
8 SO
MP3 Players
Cell Phones
Two-Way Pagers
Hand-Held Computers
Functional Diagrams
Typical Operating Circuit
TO LOAD
BATT
4.35V TO 6.5V
SINGLE
Li+
CELL
IN
4.2V
TOP VIEW
SELV
1
8
CHG
SELI
2
7
EN
3
6
GND
IN 4
5
BATT
SELV
4.1V
ON
TO IN
MAX1811
MAX1811
LED
GND
EN
OFF
CHG
500mA
100mA
Pin Configuration
SELI
GND
CHG
LOGIC OUT
SO
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
* P2
UCSP is a trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-2024; Rev 2; 6/03
MAX1811
USB-Powered Li+ Charger
ABSOLUTE MAXIMUM RATINGS
IN, BATT, SELI, CHG, EN to GND ..............................-0.3V to 7V
SELV to GND ...............................................-0.3V to (VIN + 0.3V)
Continuous Power Dissipation (TA = +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
(VIN = 4.5V, EN = IN, TA = 0°C to +85°C, unless otherwise noted.)
PARAMETER
CONDITIONS
Input Supply Voltage
Input Undervoltage Lockout
IIN rising
MIN
Charging Headroom
Precondition Threshold
MAX
UNITS
6.50
V
3.75
4.05
V
Input Undervoltage Lockout Hysteresis
Input Supply Current
TYP
4.35
50
mV
Operating, EN = IN, no load
0.9
2.0
mA
Shutdown, EN = GND
2.5
5.0
µA
SELI = GND (100mA mode),
VIN = 4.35V
SELI = IN (500mA mode)
BATT rising, transition from precondition to
charge mode
100
mV
200
2.3
Precondition Threshold Hysteresis
2.5
2.7
80
V
mV
CHG Output Leakage Current
VIN = V CHG = 6.5V
0.1
1.0
µA
CHG Output Low Voltage
ISINK = 10mA
VSELI = VIN = 5.5V, VBATT = 2.7V
SELI = GND, VIN = 5.5V, VBATT = 2.7V
VBATT = 2V, SELI = GND or IN
SELV = GND, IBATT = 0
20
4.08
0.4
500
100
70
4.12
V
455
85
43
4.10
SELV = IN, IBATT = 0
4.18
4.20
4.22
1
5
µA
2
µA
Charging Current
BATT Regulation Voltage
BATT Leakage Current (Input
Power Removed)
VBATT = 4.2V, EN = IN = GND
V
BATT Shutdown Current
EN = GND, VBATT = 4.2V
Logic Input Low Voltage (EN, SELI, SELV)
VIN = 4.35V to 6.5V
Logic Input High Voltage (EN, SELI, SELV)
VIN = 4.35V to 6.5V
Logic Input Leakage Current (EN, SELI)
VIN = 0 to 6.5V; VSELI, VEN = 6.5V or GND
1
µA
Logic Input Leakage Current (SELV)
VIN = 0 to 6.5V, VSELV = VIN or GND
1
µA
Thermal Regulation
Die temperature beyond which charging
current is reduced
2
0.1
mA
0.8
2.0
V
V
125
°C
Maxim Integrated
MAX1811
USB-Powered Li+ Charger
ELECTRICAL CHARACTERISTICS
(VIN = 4.5V, TA = -40°C to +85°C, unless otherwise noted.) (Note1)
PARAMETER
CONDITIONS
MIN
Input Supply Voltage
Input Undervoltage Lockout
Precondition Threshold
BATT Regulation Voltage
MAX
UNITS
6.50
V
3.75
4.05
V
Operating, EN = IN, no load
3
mA
Shutdown, EN = GND
6
µA
V
IIN rising
Input Supply Current
TYP
4.35
BATT rising, transition from precondition to
charge mode
2.3
2.7
SELV = GND, IBATT = 0
4.06
4.14
SELV = IN, IBATT = 0
4.16
4.24
V
BATT Leakage Current (Input
Power Removed)
VBATT = 4.2V, IN = GND
10
µA
BATT Shutdown Current
EN = GND, VBATT = 4.2V
3
µA
Note 1: Specifications to -40°C are guaranteed by design and not production tested.
Typical Operating Characteristics
(CHG unconnected, CBATT = 2.2µF, TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. INPUT VOLTAGE
(SHUTDOWN)
0.8
3.5
0.7
450
350
VSELI = 0
0.4
IBATT (mA)
0.5
2.5
2.0
1.5
0.3
300
250
150
1.0
100
0.1
0.5
50
0
0
1
2
3
4
VIN (V)
Maxim Integrated
5
6
7
VBATT = 4.1V
VSELV = VIN
200
0.2
0
VSELI = VIN
400
3.0
VSELI = VIN
0.6
IIN (µA)
IIN (mA)
VIN = VSELV
VEN = 0
4.0
500
MAX1811 toc02
VIN = VEN = VSELV
0.9
4.5
MAX1811 toc01
1.0
CHARGE CURRENT
vs. INPUT VOLTAGE HEADROOM
MAX1811 toc03
SUPPLY CURRENT
vs. INPUT VOLTAGE (ENABLED)
VSELI = 0
0
0
1
2
3
4
VIN (V)
5
6
7
0
0.5
1.0
1.5
2.0
2.5
3.0
VIN - VBATT (V)
3
MAX1811
USB-Powered Li+ Charger
Typical Operating Characteristics (continued)
(CHG unconnected, CBATT = 2.2µF, TA = +25°C, unless otherwise noted.)
CHARGE CURENT
vs. INPUT VOLTAGE
VSELI = VIN
200
VSELI = 0
300
VSELI = VIN
250
VSELI = 0
200
150
100
50
100
0
50
-50
0
0
1
2
3
4
5
6
-15
10
35
60
85
TEMPERATURE (°C)
MAX1811 toc07
600
VIN = VSELV = VEN = 6.5V, VBATT = 2.7V
500
VSELI = VIN
VSELI = VIN
400
IBATT (mA)
IBATT (mA)
-40
CHARGE CURRENT vs. TEMPERATURE
WITH THERMAL REGULATION
500
300
200
300
200
VSELI = 0
THERMAL CONTROL
LOOP IN OPERATION
VSELI = 0
100
0
0
-40
-15
10
35
TEMPERATURE (°C)
4
7
VIN (V)
VIN = VSELV = VEN = 5.5V, VBATT = 2.7V
100
VSELV = 0
4.08
CHARGE CURRENT
vs. TEMPERATURE
400
4.14
4.10
VBATT (V)
600
VIN = VSELI = VEN = 4.5V
IBATT = 0
4.16
4.12
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
VSELV = VIN
4.18
VBATT (V)
250
150
4.20
350
300
IBATT (mA)
IBATT (mA)
350
400
MAX1811 toc08
400
VBATT = 4.1V
VSELV = VIN
450
4.22
MAX1811 toc05
VIN = VEN = VSELV = 5.5V
450
500
MAX1811 toc04
500
BATTERY REGULATION VOLTAGE
vs. TEMPERATURE
MAX1811 toc06
CHARGE CURRENT
vs. BATTERY CURRENT
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
Maxim Integrated
MAX1811
USB-Powered Li+ Charger
Pin Description
PIN
NAME
DESCRIPTION
1
SELV
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.
2
SELI
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 VSELI can exceed the voltage at VIN.
3, 6
GND
Ground. Connect pins 3 and 6 to a large copper trace for maximum power dissipation.
4
IN
5
BATT
7
EN
8
CHG
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
< VBATT < BATT Regulation Voltage).
IN
SELI
VOLTAGE
LOOP
CURRENT
SELECTOR
REGULATOR
BATT
THERMAL
LOOP
3V
CHG
EN
VOLTAGE
SELECTOR
BIAS
OVERCURRENT
DETECTOR
(2.5V, 4.2V)
4.7V
BATTERY
OVERVOLTAGE
DETECTOR
2V
MAX
DETECTOR
CIRCUIT
CURRENT
LOOP
MAX1811
CURRENTSENSE
CIRCUIT
SELV
GND
Figure 1. Functional Diagram
Maxim Integrated
5
MAX1811
USB-Powered Li+ Charger
Detailed Description
Charger-Control Circuitry
The voltage/current regulator consists of a voltage control loop, a current control loop, and a thermal control
loop (Figure 1). Use the SELV input to set the battery
regulation voltage to a 4.1V or 4.2V single Li+ cell. The
current and thermal loops are internally compensated
and require no external compensation. The outputs
from all loops drive an internal linear regulator. The
thermal loop modulates the current loop by limiting the
charge current if the die temperature exceeds +125°C.
The MAX1811 is in current mode when the BATT voltage is below the regulation set point and in voltage
mode when the BATT voltage is near the regulation set
point. The CHG output indicates whether the part is in
current mode (CHG = low) or voltage mode (CHG =
high impedance). Battery voltages less than 2.5V activate a 43mA preconditioning mode (CHG = high
impedance). Normal charging resumes when the battery voltage exceeds 2.5V.
System Configuration
The MAX1811 is designed to operate seamlessly with a
universal serial bus (USB) port. In a typical design, the
USB connects to the MAX1811 input, and the MAX1811
drives the load and charges the battery when enabled.
Charge-Current Selection
The MAX1811 charges a single cell Li+ battery in either
100mA or 500mA modes. The MAX1811 expects the
system to poll the USB host to determine if the USB is
capable of providing 100mA or 500mA and regulates
the charging current accordingly (Figure 2). This is to
maintain compatibility with both powered and unpowered USB hosts. A powered USB host is capable of
USB*
PORT
BATT
IN
MAX1811
4.35V TO 5.5V
SINGLE
Li+
CELL
providing 500mA, and an unpowered USB hub is limited to only 100mA.
Drive SELI low to set the charge current to the 100mA
mode. Use a 10kΩ pulldown resistor to ground on SELI,
if necessary, to ensure that the MAX1811 defaults to
the 100mA mode in the event that no logic signal is
present. Drive SELI high to increase the charge current
to the 500mA mode only if the polled USB port can provide the required current.
Thermal-Control Circuitry
The thermal loop limits the MAX1811 die temperature to
+125°C by reducing the charging current as necessary. The MAX1811 can operate normally with the thermal loop active. This is not a fault condition and can be
used continuously. The power dissipated by the internal power FET is determined by (VIN - VBATT) ✕ ICHG.
The power dissipation rating for the thermally enhanced
8-pin SO package is 1.4W at +50°C ambient (assuming
a 1in2 PC board radiating area), which is the maximum
ambient temperature at which most Li+ battery manufacturers allow charging. The 1.4W power dissipation
may never be reached due to the MAX1811’s thermal
regulation loop.
Applications Information
USB Output Voltage
The minimum voltage to a USB-powered device may
be as low as 4.35V when cable and connector drops
are considered (Figure 3). The MAX1811 is optimized
for operation at these low input voltage levels. USB
hubs may also provide as much as 5.5V. At high input
voltages (5.5V) and low cell voltages (2.7V), the
MAX1811’s thermal loop may limit the charge current
until the cell voltage rises.
SYSTEM
LOAD
*WHEN USING WALL ADAPTER, IN VOLTAGE RANGE IS FROM 4.35V TO 6.5V.
Figure 2. System Configuration
6
Maxim Integrated
MAX1811
USB-Powered Li+ Charger
Charging from AC Adapters
The MAX1811 also operates from sources other than
USB ports. The full charging input voltage range is
4.35V to 6.5V. When charging in the 500mA mode with
an AC adapter, rely on the thermal loop to limit the
power dissipation by limiting the charge current at
higher input voltages if limited PC board area is available to dissipate heat.
Capacitor Selection
Use a larger input bypass capacitor for high input voltages or high charging current to reduce supply noise.
Chip Information
TRANSISTOR COUNT: 1907
PROCESS: BiCMOS
Use a minimum of 2.2µF placed close to BATT for proper stability. Bypass IN to GND with a 4.7µF capacitor.
HOST OR
POWERED HUB
4.750V
LOW-POWER
FUNCTION
BUS-POWERED
HUB
4.735V
4.640V
4.625V
*4.400V
4.397V
4.375V
4.378V
4.500V
0.000V
0.015V
0.110V
0.125V
4.350V
0.000V
0.003V
0.002V
0.025V
REFERENCED REFERENCED
TO SOURCE TO HUB
*UNDER TRANSIENT CONDITIONS, SUPPLY AT HUB CAN DROP FROM 4.00V TO 4.070V.
Figure 3. USB Voltage Specification
TO LOAD
BATT
4.35V TO 6.5V
SINGLE
Li+
CELL
IN
4.2V
SELV
4.1V
ON
TO IN
MAX1811
LED
EN
OFF
CHG
500mA
SELI
100mA
GND
GND
CHG
LOGIC OUT
10kΩ
Figure 4. Charging from a USB Port
Maxim Integrated
7
MAX1811
USB-Powered Li+ Charger
Package Information
DIM
A
A1
B
C
e
E
H
L
N
H
E
INCHES
MILLIMETERS
MAX
MIN
0.069
0.053
0.010
0.004
0.019
0.014
0.010
0.007
0.050 BSC
0.157
0.150
0.228
0.244
0.050
0.016
MAX
MIN
1.75
1.35
0.10
0.25
0.35
0.49
0.19
0.25
1.27 BSC
3.80
4.00
5.80
6.20
0.40
SOICN .EPS
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
1.27
VARIATIONS:
1
INCHES
TOP VIEW
DIM
D
D
D
MIN
0.189
0.337
0.386
MAX
0.197
0.344
0.394
MILLIMETERS
MIN
4.80
8.55
9.80
MAX
5.00
8.75
10.00
N MS012
8
AA
14
AB
16
AC
D
A
B
e
FRONT VIEW
A1
C
0 -8
L
SIDE VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, .150" SOIC
APPROVAL
DOCUMENT CONTROL NO.
21-0041
REV.
B
1
1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
8
© Maxim Integrated
Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.