MAXIM MAX1501

19-2800; Rev 0; 4/03
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
The device achieves high flexibility by providing an
adjustable fast-charge current, top-off current, safety
timer, and thermal-regulation setpoint. Other features
include input power detection (ACOK) and input under-/
overvoltage protection. The MAX1501 provides activelow control inputs.
The MAX1501 accepts a 4.5V to 13V supply, but
disables charging when the input voltage exceeds
6.5V, preventing excessive power dissipation. The
MAX1501 operates over the extended temperature
range (-40°C to +85°C) and is available in a compact
16-pin thermally enhanced 5mm x 5mm thin QFN
package with 0.8mm profile.
Features
♦ Stand-Alone or Microprocessor-Controlled (µP)
Linear 1-Cell Li+ or 3-Cell NiMH/NiCd Battery
Charger
♦ No FET, Reverse-Blocking Diode, or CurrentSense Resistor Required
♦ 1.4A (max) Programmable Fast-Charge Current
♦ +95°C, +115°C, and +135°C Proprietary
Programmable Die Temperature Regulation
Control
♦ 4.5V to 13V Input Voltage Range with Input
Overvoltage (OVLO) Protection Above 6.5V
♦ Programmable Top-Off Current Threshold: 10%,
20%, or 30% of the Fast-Charge Current
♦ Charge-Current Monitor for Fuel Gauging
♦ Programmable Safety Timer (3, 4.5, or 6 hours)
♦ Input Power Detection Output (ACOK) and Charge
Enable Input (CHGEN)
♦ Automatic Recharge
♦ Digital Soft-Start Limits Inrush Current
♦ Charge Status Outputs for LEDs or µP Interface
Ordering Information
PART
MAX1501ETE
TEMP RANGE
PIN-PACKAGE
-40°C to +85°C
16 Thin QFN
Typical Operating Circuit
INPUT
4.5V TO 13V
4.2V 1-CELL Li+
IN
Applications
1µF
BATT
10µF
INP
Cellular and Cordless Phones
MAX1501
PDAs
FULLI
Digital Cameras and MP3 Players
GLED
VL
USB Appliances
RLED
SELV
Charging Cradles and Docks
TEMP
MODE
Bluetooth™ Equipment
TMAX
CHGEN
VLOGIC
(≤ 5.5V)
RPULLUP
SETI
Pin Configuration appears at end of data sheet.
ACOK
2.8kΩ
GND
Bluetooth is a trademark of Ericsson.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX1501
General Description
The MAX1501 intelligent, constant-current, constantvoltage (CCCV), temperature-regulated battery charger
charges a single lithium-ion (Li+) cell or three-cell
NiMH/NiCd batteries. The device integrates the currentsense resistor, PMOS pass element, and thermalregulation circuitry, while eliminating the reverseblocking Schottky diode to create the simplest charging
solution for hand-held equipment.
The MAX1501 functions as a stand-alone charger to
control the charging sequence from the prequalification
state through fast charge, top-off, and charge termination
for single-cell Li+ or three-cell NiMH/NiCd batteries.
Alternatively, the MAX1501 collaborates with a host
microprocessor to determine the best charging algorithm.
Proprietary thermal-regulation circuitry limits the die
temperature when fast charging or while exposed to high
ambient temperatures, allowing maximum charging
current without damaging the charger. The MAX1501
continually supplies a regulated output voltage under
no-battery conditions, allowing battery changing.
MAX1501
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
ABSOLUTE MAXIMUM RATINGS
IN, INP, RLED, GLED to GND ................................-0.3V to +14V
IN to INP ................................................................-0.3V to +0.3V
VL, BATT, SETI, ACOK, MODE, CHGEN, SELV,
FULLI, TMAX, TEMP to GND ................................-0.3V to +6V
VL to IN...................................................................-14V to +0.3V
Continuous Power Dissipation (TA = +70°C)
16-Pin 5mm ✕ 5mm Thin QFN
(derate 21.3mW/°C above +70°C) .............................1702mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +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 = VINP = 5V, VBATT = 3.5V, ACOK = GLED = RLED = TEMP = TMAX = FULLI = open, CHGEN = MODE = GND, RSETI = 2.8kΩ,
CIN = 1µF, CBATT = 10µF, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
CONDITIONS
IN, INP Input Voltage
MIN
TYP
0
IN, INP Input Operating Range
UNITS
13
V
6.25
V
4.5V ≤ VIN ≤ 6.25V, IVL < 250µA
2.7
3
3.3
V
VIN - VBATT, rising
40
70
100
ACOK Trip Point
VIN - VBATT, falling
30
55
85
ACOK Sink Current
4.5V ≤ VIN ≤ 6.25V, V ACOK = 0.6V
VL Output Voltage
4.50
MAX
VIN - VBATT, hysteresis
Undervoltage Lockout Trip Point
15
75
4.05
4.125
4.20
VIN falling
3.9
4.025
4.1
6.25
6.50
100
VIN rising
Li+, NiMH/NiCd, and no-battery modes
IN Input Current
µA
VIN rising
Hysteresis
Overvoltage Lockout Trip Point
Disable mode
Leakage into Battery
5
8
3
45
80
VIN = 0
3
10
Disable mode
2
6
Disable mode
RMS Charge Current
Li+ mode
Battery Regulation Voltage
NiMH/NiCd mode
V
mA
0.25
VBATT = 4.3V
VIN = VINP = 13V, VBATT = 0
V
mV
6.75
1.5
Off mode (VIN = 4V)
BATT Input Current
mV
5
µA
1.4
A
SELV = VL
4.166
4.2
4.234
SELV = GND
4.067
4.1
4.133
SELV = VL,
VIN = VINP = 6V
4.85
4.95
5.05
SELV = GND
µA
V
4.4
4.5
4.6
Output Regulation Voltage
No-battery mode
3.700
4.0
4.234
V
BATT Precharge Threshold
Voltage
BATT rising
2.675
2.8
2.925
V
Fast-Charge Current-Loop
System Accuracy
2
RSETI = 2.8kΩ
460
500
540
RSETI = 1.75 kΩ
736
800
864
_______________________________________________________________________________________
mA
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
(VIN = VINP = 5V, VBATT = 3.5V, ACOK = GLED = RLED = TEMP = TMAX = FULLI = open, CHGEN = MODE = GND, RSETI = 2.8kΩ,
CIN = 1µF, CBATT = 10µF, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Precharge Current System
Accuracy
Die Temperature Regulation
Setpoint (Note 1)
Current-Sense Amplifier Gain
CONDITIONS
% of fast-charge current, VBATT = 2V
MIN
TYP
MAX
UNITS
5
10
15
%
TEMP = GND
95
TEMP = open
115
TEMP = VL
135
IBATT to ISETI, precharge mode, VBATT = 2V
0.70
1
1.30
IBATT to ISETI, fast-charge mode
0.95
1
1.05
Internal Current-Sense
Resistance
84
Regulator Dropout Voltage
VIN - VBATT, NiMH/NiCd mode, VBATT = 4.3V,
IBATT = 425mA
Logic Input Low Voltage
CHGEN, MODE, 4.5V ≤ VIN ≤ 6.25V
Logic Input High Voltage
CHGEN, MODE, 4.5V ≤ VIN ≤ 6.25V
1.25
Internal Pulldown Resistance
CHGEN, MODE
100
Internal Pullup Resistance
SELV
100
Internal Bias Resistance
FULLI, TEMP, TMAX
50
Internal Bias Voltage
FULLI, TEMP, TMAX
RLED Output Low Current
V RLED = 1V
7
GLED Output Low Current
V GLED = 1V
14
GLED, RLED Output High
Leakage Current
V GLED = V RLED = VIN = VINP = 13V
Full-Battery Detection Current
Threshold
% of fast-charge
current
VBATT Restart Threshold
Li+ mode
NiMH/NiCd mode
Charge-Timer Accuracy
Charge-Timer Duration
o
190
350
mV
0.52
V
175
400
kΩ
175
400
kΩ
90
200
kΩ
10
18
mA
20
34
mA
0.1
1
µA
V
VVL/2
V
5
10
15
FULLI = VL
15
20
25
FULLI = open
25
30
35
SELV = VL
3.9
4.0
4.1
3.8
3.9
4.0
3.9
4.0
4.1
-10
+10
TMAX = GND
3
TMAX = open
4.5
TMAX = VL
mA/A
mΩ
FULLI = GND
SELV = GND
C
%
V
%
hrs
6
_______________________________________________________________________________________
3
MAX1501
ELECTRICAL CHARACTERISTICS (continued)
MAX1501
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
ELECTRICAL CHARACTERISTICS
(VIN = VINP = 5V, VBATT = 3.5V, ACOK = GLED = RLED = TEMP = TMAX = FULLI = open, CHGEN = MODE = GND, RSETI = 2.8kΩ,
CIN = 1µF, CBATT = 10µF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
CONDITIONS
IN, INP Input Voltage
IN, INP Input Operating Range
VL Output Voltage
ACOK Trip Point
ACOK Sink Current
Undervoltage Lockout Trip Point
BATT Input Current
Leakage into Battery
TYP
MAX
13
V
4.50
6.25
V
V
2.7
3.3
VIN - VBATT, rising
40
100
VIN - VBATT, falling
30
85
4.5V ≤ VIN ≤ 6.25V, V ACOK = 0.6V
75
4.00
4.25
VIN falling
3.90
4.15
6.25
6.75
Li+, NiMH/NiCd, and no-battery modes
8
Disable mode
3
VBATT = 4.3V
80
VIN = 0
10
Disable mode
6
Disable mode
RMS Charge Current
Li+ mode
Battery Regulation Voltage
NiMH/NiCd mode
V
V
mA
µA
5
µA
1.4
A
SELV = VL
4.148
4.252
SELV = GND
4.05
4.15
SELV = VL
4.85
5.05
V
4.4
4.6
Output Regulation Voltage
No-battery mode
3.700
4.234
V
BATT Precharge Threshold
Voltage
BATT rising
2.675
2.925
V
RSETI = 2.8kΩ
460
540
RSETI = 1.75kΩ
736
864
5
15
Fast-Charge Current-Loop
System Accuracy
Precharge Current System
Accuracy
Current-Sense Amplifier Gain
SELV = GND
mV
µA
VIN rising
VIN = VINP = 13V, VBATT = 0
UNITS
0
4.5V ≤ VIN ≤ 6.25V, IVL < 250µA
Overvoltage Lockout Trip Point
IN Input Current
MIN
% of fast-charge current, VBATT = 2V
IBATT to ISETI, precharge mode, VBATT = 2V
0.60
1.40
IBATT to ISETI, fast-charge mode
0.93
1.07
Regulator Dropout Voltage
VIN - VBATT, NiMH/NiCd mode, VBATT = 4.3V,
IBATT = 425mA
Logic Input Low Voltage
CHGEN, MODE, 4.5V < VIN < 6.25V
Logic Input High Voltage
CHGEN, MODE, 4.5V < VIN < 6.25V
350
0.52
1.3
mA
%
mA/A
mV
V
V
Internal Pulldown Resistance
CHGEN, MODE
100
400
Internal Pullup Resistance
SELV
100
400
kΩ
Internal Bias Resistance
FULLI, TEMP, TMAX
50
200
kΩ
4
_______________________________________________________________________________________
kΩ
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
(VIN = VINP = 5V, VBATT = 3.5V, ACOK = GLED = RLED = TEMP = TMAX = FULLI = open, CHGEN = MODE = GND, RSETI = 2.8kΩ,
CIN = 1µF, CBATT = 10µF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
RLED Output Low Current
V RLED = 1V
7
18
mA
GLED Output Low Current
V GLED = 1V
14
34
mA
GLED, RLED Output High
Leakage Current
V GLED = V RLED = VIN = VINP = 13V
1
µA
+10
%
Charge-Timer Accuracy
-10
Note 1: Temperature regulation setpoint variation is typically ±9°C.
Note 2: Specifications to TA = -40°C are guaranteed by design, not production tested.
Typical Operating Characteristics
(VIN = VINP = 5V, ACOK = RLED = GLED = TEMP = TMAX = FULLI = open, CBATT = 10µF, CIN = 1µF, TA = +25°C, unless otherwise noted.)
DISABLE-MODE SUPPLY CURRENT
vs. INPUT VOLTAGE
2.5
2.0
1.5
1.0
0.5
0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
350
300
250
200
150
100
0 1 2 3 4 5 6 7 8 9 10 11 12 13
0 1 2 3 4 5 6 7 8 9 10 11 12 13
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
BATTERY VOLTAGE (V)
CHARGE CURRENT
vs. BATTERY VOLTAGE
CHARGE CURRENT
vs. INPUT VOLTAGE
CHARGE CURRENT
vs. INPUT-VOLTAGE HEADROOM
CHARGE CURRENT (mA)
400
350
300
250
200
150
100
50
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
BATTERY VOLTAGE (V)
500
450
0
Li+ MODE,
SELV = VL,
RSETI = 2.7kΩ
400
350
300
250
200
150
100
50
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13
INPUT VOLTAGE (V)
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
600
550
CHARGE CURRENT (mA)
600
550
MAX1501 toc04
NiMH/NiCd, RSETI = 2.7kΩ,
VIN = 5.5V, SELV = VL
550
500
450
MAX1501 toc03
400
50
0
0
600
CHARGE CURRENT (mA)
1.6
Li+ MODE, RSETI = 2.7kΩ,
VIN = 5V, SELV = VL
500
450
500
450
NiMH/NiCd MODE, SELV = GND,
RSETI = 2.7kΩ, VBATT = 4.3V
400
350
MAX1501 toc06
3.0
600
550
CHARGE CURRENT (mA)
3.5
1.8
MAX1501 toc05
SUPPLY CURRENT (mA)
4.0
2.0
CHARGE CURRENT
vs. BATTERY VOLTAGE
MAX1501 toc02
Li+ MODE OR
NiMH/NiCd MODE,
SELV = VL, IBATT = 0
4.5
DISABLE-MODE SUPPLY CURRENT (mA)
5.0
MAX1501 toc01
SUPPLY CURRENT vs. INPUT VOLTAGE
300
250
200
150
100
50
0
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
VIN - VBATT (V)
_______________________________________________________________________________________
5
MAX1501
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(VIN = VINP = 5V, ACOK = RLED = GLED = TEMP = TMAX = FULLI = open, CBATT = 10µF, CIN = 1µF, TA = +25°C, unless otherwise noted.)
BATTERY REGULATION VOLTAGE
vs. TEMPERATURE
3.0
2.5
2.0
1.5
1.0
0.5
Li+ MODE
0
4.20
4.16
4.14
4.12
4.08
-15
10
35
60
TEMPERATURE (°C)
CHARGE CURRENT
vs. AMBIENT TEMPERATURE
CHARGE CURRENT
vs. AMBIENT TEMPERATURE
1000
MAX1501 toc09
900
800
CHARGE CURRENT (mA)
Li+ MODE, TEMP = VL,
VBATT = 3.6V, VIN = 5V,
RSETI = 2.7kΩ
540
520
500
480
460
700
600
85
Li+ MODE, TEMP = VL,
VBATT = 3.6V,
VIN = 6V, RSETI = 1.75kΩ
500
400
300
440
200
420
100
400
0
-40
-15
10
35
60
AMBIENT TEMPERATURE (°C)
6
-40
INPUT VOLTAGE (V)
600
560
SELV = GND
4.10
0 1 2 3 4 5 6 7 8 9 10 11 12 13
580
SELV = VL
4.18
MAX1501 toc10
OUTPUT VOLTAGE (V)
3.5
4.22
MAX1501 toc08
NO BATTERY MODE
IBATT = 0
BATTERY REGULATION VOLTAGE (V)
4.0
MAX1501 toc07
OUTPUT VOLTAGE vs. INPUT VOLTAGE
CHARGE CURRENT (mA)
MAX1501
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
85
-40
-15
10
35
60
AMBIENT TEMPERATURE (°C)
_______________________________________________________________________________________
85
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
PIN
NAME
1
INP
2
IN
3, 13
GND
Ground. Connect the exposed paddle to GND.
4
SETI
Current-Sense Transconductance Amplifier Output. Connect a resistor from SETI to GND to program the
maximum charge current and to monitor the actual charge current. SETI pulls to GND during shutdown.
5
VL
Linear Regulator Output. Connect CHGEN, TEMP, TMAX, FULLI, and MODE to VL to program logic high.
VL discharges to GND during shutdown.
TMAX
Maximum Charging-Time Select Input. TMAX sets the maximum charging time. Connect TMAX to GND to
set the maximum charging time to 3 hours. Leave TMAX floating to set the maximum charging time to 4.5
hours. Connect TMAX to VL to set the maximum charging time to 6 hours. TMAX pulls to GND through a
50kΩ resistor in shutdown.
FULLI
Top-Off-Current Select Input. FULLI sets the end-of-charge threshold as a percentage of the fast-charge
current. Connect FULLI to GND to set the end-of-charge threshold to 10% of the fast-charge current.
Connect FULLI to VL to set the end-of-charge threshold to 20% of the fast-charge current. Leave FULLI
floating to set the end-of-charge threshold to 30% of the fast-charge current. FULLI pulls to GND through
a 50kΩ resistor in shutdown.
8
TEMP
Die Temperature Select Input. TEMP sets the die temperature regulation point for the thermal-control
loop. Connect TEMP to GND to regulate the die temperature at +95°C. Leave TEMP floating to regulate
the die temperature at +115°C. Connect TEMP to VL to regulate the die temperature at +135°C. TEMP
pulls to GND through a 50kΩ resistor in shutdown.
9
MODE
Mode Select Input. MODE and CHGEN together control charging functions (Table 1). An internal 175kΩ
pulldown resistor pulls MODE low.
10
CHGEN
11
ACOK
Input Voltage Range Indicator. The open-drain ACOK output asserts low when 4.2V ≤ VIN ≤ 6.25V and
VIN - VBATT ≥ 100mV. ACOK requires an external 100kΩ pullup resistor. ACOK floats in shutdown.
12
BATT
Battery Connection. Connect the positive terminal of the battery to BATT. BATT draws less than 5µA
during shutdown.
14
SELV
Battery Voltage Selection Input. SELV sets the battery regulation voltage in Li+ and NiMH/NiCd modes
(Table 2). For no-battery mode, the battery voltage defaults to 4.0V. An internal 175kΩ resistor to VL pulls
SELV high.
RLED
Battery Charging Indicator. Connect the anode of a red LED to IN and the cathode to RLED. RLED
asserts low when the input supply is present and the battery is charging, regardless of cell chemistry.
RLED sinks 10mA. RLED goes high impedance in shutdown. Connect a pullup resistor to the µP’s I/O
supply when interfacing with a µP logic input.
GLED
Full-Charge Indicator. Connect the anode of a green LED to IN and the cathode to GLED. GLED asserts
low when the input supply is present and the battery has reached the top-off current threshold set by
FULLI, regardless of cell chemistry. GLED sinks 20mA. GLED goes high impedance in shutdown.
Connect a pullup resistor to the µP’s I/O supply when interfacing with a µP logic input.
6
7
15
16
FUNCTION
High-Current Charger Input. Connect an AC adapter to INP and IN as close to the device as possible.
INP provides charge current to the battery. INP draws current while the device is in shutdown mode.
Low-Current Charger Input. Bypass IN to GND with a 1µF ceramic capacitor. Connect IN to INP as close
to the device as possible. IN powers the internal LDO and reference. IN draws current while the device is
in shutdown mode.
Charge Enable Input. CHGEN and MODE together control charging functions (Table 1). An internal
175kΩ pulldown resistor pulls CHGEN low.
_______________________________________________________________________________________
7
MAX1501
Pin Description
MAX1501
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
MAX1501
INP
BATT
VREF
CS
OUTPUT DRIVER
AND LOGIC
SETI
TEMP REF
TEMPERATURE
SENSOR
IREF
IN
SHUTDOWN
UVLO
VL
CHGEN
VL
MODE
REF
SELV
OVLO
ON
LOGIC
TEMP
ACOK
RLED
FULLI
GLED
OSC
GND
TMAX
GND
Figure 1. Functional Diagram
8
_______________________________________________________________________________________
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
MAX1501
OFF
ACOK = HIGH
CHARGER OFF
ACOK = LOW
RLED = OFF
GLED = OFF
ACOK = (4.2V < VIN < 6.25V) AND (VIN - VBATT > 100mV)
ACOK = LOW
CHGEN = LOW
VBATT < 2.8V
CHGEN = HIGH
MODE = LOW
NOBATT
DISABLE
PREQUAL
CHARGER OFF
ACOK = LOW
RLED = OFF
GLED = OFF
10% SETI CURRENT
ACOK = LOW
RLED = ON
GLED = OFF
CHGEN = LOW
SOFT-START
CHGEN = HIGH
MODE = HIGH
(CURRENT LIMITED AND
CHGEN = LOW THERMALLY PROTECTED)
ACOK = LOW
RLED = OFF
GLED = OFF
SOFT-START
VBATT < 2.8V
FAST CHARGE
(THERMALLY PROTECTED)
100% SETI CURRENT
ACOK = LOW
RLED = ON
GLED = OFF
ICHG < ITOP-OFF
TIME > TMAX
VBATT < 4V (Li+ MODE, SELV = VL, AND NiMH/NiCd MODE)
VBATT < 3.9V (Li+ MODE, SELV = GND)
TOP OFF
(VOLTAGE LOOP)
RLED = OFF
GLED = ON
TIME > TMAX
DONE
CHARGER OFF
RLED = OFF
GLED = ON
Figure 2. Charge State Diagram
Detailed Description
Modes of Operation
CHGEN and MODE together set the operating modes
of the MAX1501. Both inputs possess internal 175kΩ
pulldown resistors to GND. Table 1 describes the four
operating modes of the MAX1501.
Table 1. Modes of Operation
MODE
Li+ Charge Mode
CHGEN
MODE
0
0
NiMH/NiCd Charge Mode
0
1
Disable Mode
1
0
No-Battery Mode
1
1
_______________________________________________________________________________________
9
MAX1501
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
The thermal-regulation loop limits the MAX1501 die
temperature to the value selected by the TEMP input by
reducing the charge current as necessary (see the
Thermal-Regulation Selection section). This feature not
only protects the MAX1501 from overheating, but also
allows the charge current to be set higher without
risking damage to the system.
Table 2. Battery Regulation Voltage
SELV
CHARGING MODE
GND
VL
Li+
4.1V
4.2V
NiMH/NiCd
4.5V
4.95V
Li+ Charge Mode
Connect CHGEN and MODE to GND to place the
MAX1501 in Li+ charging mode. The Li+ charger consists of a voltage-control loop, a current-control loop,
and a thermal-control loop. Connect SELV to GND to
set the Li+ battery voltage to 4.1V. Connect SELV to VL
to set the Li+ battery voltage to 4.2V (Table 2).
The MAX1501 precharges the Li+ battery with 10% of
the user-programmed fast-charge current at the start of
a charge cycle. A soft-start algorithm ramps up the
charging current (10% steps with 20ms duration per
step) to the fast-charge current when the battery voltage reaches 2.8V. The MAX1501 enters constant-voltage mode and decreases the charge current when the
BATT voltage reaches the selected regulation voltage
(4.1V or 4.2V). Set the fast-charge current with a resistor between SETI and GND (see the Charge-Current
Selection section).
REGULATION VOLTAGE
PREQUALIFICATION
Set the top-off-current threshold with the three-state
FULLI input (see the Top-Off-Current Selection section).
RLED goes high impedance and GLED asserts low when
the top-off-current threshold is reached. The MAX1501
automatically initiates recharging when the battery voltage drops below 95% of the voltage set by SELV.
NiMH/NiCd Charge Mode
Connect CHGEN to GND and MODE to VL to place the
MAX1501 in NiMH/NiCd charging mode. The
NiMH/NiCd battery charger consists of a current-control loop, a voltage-control loop, and a thermal-control
loop. Connect SELV to GND to set the regulation voltage to 4.5V. Connect SELV to VL to set the regulation
voltage to 4.95V (Table 2). When charging three
NiMH/NiCd cells to 4.95V, VIN must be at least 5.25V
and a µP must be used to terminate the charge
sequence.
FAST CHARGING
TOP-OFF
DONE
FAST-CHARGE CURRENT
BATTERY
CURRENT
RLED TURNS OFF AND GLED
TURNS ON WHEN CHARGE CURRENT
DROPS TO VALUE SET BY FULLI
(10%, 20%, OR 30% OF FASTCHARGE CURRENT).
BATTERY
VOLTAGE
MINIMUM CHARGE VOLTAGE
(2.8V)
CHARGE
TERMINATED
10% OF FAST-CHARGE CURRENT
tPREQUAL
tMAX
Figure 3. Li+ Charge Sequence
10
______________________________________________________________________________________
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
MODE
Li+ Mode or
NiMH/NiCd Mode
STATE
• 10% current-limited precharge
• Current-limited charge
• Voltage-limited charge before top-off
• Temperature-limited charge before top-off
• Voltage-limited charge after top-off
• Safety timer expires
RLED
GLED
Sinks 10mA
High impedance
High impedance
Sinks 20mA
Disable Mode
—
High impedance
High impedance
No Battery Mode
—
High impedance
High impedance
The MAX1501 precharges the NiMH/NiCd battery with
10% of the user-programmed fast-charge current at the
start of a charge cycle. Precharge ends and fast
charge begins when the battery voltage exceeds 2.8V.
Set the fast-charge current with a resistor between SETI
and GND (see the Charge-Current Selection section).
The MAX1501 enters constant-voltage mode and
decreases the charge current when the battery voltage
reaches 4.5V.
The thermal-regulation loop limits the MAX1501 die
temperature to the value selected by the TEMP input by
reducing the charge current as necessary (see the
Thermal-Regulation Selection section). This feature protects the MAX1501 from overheating when supplying
high charge currents, or while operating from high input
voltages.
Set the top-off-current threshold with the three-state
FULLI input (see the Top-Off-Current Selection section).
RLED goes high impedance and GLED asserts low
when the top-off current threshold is reached. The
MAX1501 automatically initiates recharging when the
battery voltage drops below 4V.
No-Battery Mode
Connect CHGEN and MODE to VL to place the MAX1501
in no-battery mode. An external load can be connected to
BATT in this mode. VBATT regulates to 4V in no-battery
mode, regardless of the state of SELV.
The current-control loop, voltage-control loop, and
thermal-control loop all function in no-battery mode.
The loop gain of the voltage-control loop decreases to
ensure stability with no battery present. Connect a 10µF
ceramic capacitor to BATT for stability. RLED and
GLED are both high impedance in no-battery mode.
ACOK
The ACOK output asserts low when VIN is present, 4.2V
≤ VIN ≤ 6.25V, and VIN - VBATT > 100mV. The ACOK
open-drain output requires an external 100kΩ pullup
MAX1501
Table 3. RLED and GLED Behavior
resistor to an external supply voltage. The external
supply voltage must be less than 5.5V.
RLED and GLED Indicators
RLED and GLED serve as visual indicators that power
is applied as well as the charge status of a battery.
RLED asserts low when a wall adapter is connected
and a battery is charging, regardless of cell chemistry.
GLED asserts low when power is applied and the battery is fully charged. Both outputs go high-impedance
in shutdown. Connect the anode of each LED to IN,
and the cathode to RLED or GLED. Table 3 summarizes the behavior of RLED and GLED under normal
operating conditions. Connect pullup resistors to the µP
I/O supply when interfacing RLED and GLED with a
µP’s logic inputs.
Soft-Start
A ten-step, soft-start algorithm activates when entering
fast-charge mode. The charging current ramps up in
10% increments, 20ms per step, to the full charging
current when VBATT exceeds 2.8V.
Applications Information
Charge-Current Selection
Program the charging current using an external resistor
between SETI and GND. Set the charge-current resistor
with the following equation:
RSETI = 1000 ×
1.4V
IBATT
If VSETI = 1.4V, the current-control loop controls the
battery charging. If VSETI < 1.4V, either the voltagecontrol loop or the thermal-control loop operates.
Measure the charging current by monitoring VSETI and
using the following equation:
I
VSETI = BATT × RSETI
1000
______________________________________________________________________________________
11
MAX1501
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
Thermal-Regulation Selection
Set the regulated die temperature of the MAX1501 with
the TEMP three-level logic input. The MAX1501
reduces the charge current to limit the die temperature
to the value set by TEMP. The MAX1501 operates normally while the thermal loop is active. An active thermal
loop does not indicate a fault condition. TEMP allows
the MAX1501 to maximize the charge current while providing protection against excessive power dissipation.
Connect TEMP to GND to regulate the die temperature
at +95°C. Leave TEMP floating to regulate the die temperature at +115°C. Connect TEMP to VL to regulate
the die temperature at +135°C.
Top-Off-Current Selection
Set the top-off-current threshold in the Li+ and
NiMH/NiCd charge modes with the FULLI three-level
logic input. The top-off-current threshold determines
when RLED turns off and GLED turns on, indicating the
charge status of the battery.
Connect FULLI to GND to set the top-off-current threshold to 10% of the fast-charge current. Connect FULLI to
VL to set the top-off-current threshold to 20% of the
fast-charge current. Leave FULLI floating to set the topoff-current threshold to 30% of the fast-charge current.
Charge-Timer Selection
Set the maximum charging time with the TMAX threelevel logic input. TMAX limits the duration of charging to
protect the battery from overcharging. Connect TMAX
to GND to set the maximum charging time to 3 hours.
Leave TMAX floating to set the maximum charging time
AC
ADAPTER
4.5V TO 6.5V
Capacitor Selection
Connect a ceramic capacitor from BATT to GND for
proper stability. Use a 10µF X5R ceramic capacitor for
most applications.
Connect IN and INP together and bypass to GND with
a 1µF ceramic capacitor. Use a larger input bypass
capacitor for high input voltages or high charging currents to reduce supply noise.
Thermal Considerations
The MAX1501 is available in a thermally enhanced thin
QFN package with exposed paddle. Connect the
exposed paddle of the MAX1501 to a large copper
ground plane to provide a thermal contact between the
device and the circuit board. The exposed paddle
transfers heat away from the device, allowing the
MAX1501 to charge the battery with maximum current,
while minimizing the increase in die temperature.
Application Circuits
Figure 4 shows the MAX1501 as a stand-alone Li+ battery charger. The 2.8kΩ resistor connected to SETI sets
a charging current of 500mA.
Figure 5 shows the MAX1501 as a µP-based Li+ battery
charger. Drive CHGEN low to charge the battery. Drive
CHGEN high to disable the charger. Connect a 100kΩ
pullup resistor from ACOK to the logic supply voltage of
the µP to detect the presence of an input supply. The
logic supply voltage must be less than 5.5V.
4.2V 1-CELL Li+
IN
1µF
to 4.5 hours. Connect TMAX to VL to set the maximum
charging time to 6 hours.
BATT
10µF
INP
AC
ADAPTER
4.5V TO 6.5V
4.2V 1-CELL Li+
IN
1µF
BATT
10µF
INP
MAX1501
MAX1501
GLED
MODE
RLED
CHGEN
TMAX
VI/O
ACOK
TEMP
TEMP
FULLI
VL
SELV
ACOK
µP
CHGEN
VL
SELV
SETI
SETI
GND GND
Figure 4. Stand-Alone Li+ Battery Charger
12
TMAX
RLED
RPULLUP
FULLI
2.8kΩ
GLED
2.8kΩ
MODE GND GND
Figure 5. µP-Based Li+ Battery Charger
______________________________________________________________________________________
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
4.5V 3-CELL NiMH
OR NiCd
4.75V TO 6.5V
IN
1µF
BATT
10µF
INP
4.95V
3-CELL NiMH
OR NiCd
5.25V TO 6.5V
AC
ADAPTER
IN
1µF
MAX1501
AC
ADAPTER
BATT
10µF
INP
MAX1501
MAX1501
GLED
TEMP
RLED
ACOK
TMAX
FULLI
SETI
SELV
VI/O
TMAX
RLED
TEMP
RPULLUP
FULLI
ACOK
µP
VL
2.8kΩ
GLED
VL
CHGEN
MODE
SELV
MODE
SETI
CHGEN GND GND
2.8kΩ
GND GND
Figure 6. Stand-Alone 3-Cell NiMH or NiCd Battery Charger
Figure 7. µP-Based NiMH or NiCd Battery Charge
Figure 6 shows the MAX1501 as a stand-alone
NiMH/NiCd battery charger. Connecting SELV to GND
sets the charge termination voltage to 4.5V.
Figure 7 shows the MAX1501 as a µP-based
NiMH/NiCd battery charger. Connecting SELV to VL
sets the charge regulation voltage at 4.95V. Connect a
100kΩ pullup resistor from ACOK to the logic supply
voltage of the µP. The logic supply voltage must be
less than 5.5V.
Figure 8 shows the MAX1501 as a µP-based single Li+ or
3-cell NiMH/NiCd charger. The states of MODE and
CHGEN set the operating mode of the MAX1501 (Table 1).
Connect a 100kΩ pullup resistor from ACOK to the logic
supply voltage of the µP. The logic supply voltage must be
less than 5.5V.
Figure 9 shows the MAX1501 as an accurate currentlimited low-dropout linear regulator with input overvoltage protection (no-battery mode). The output voltage
regulates to 4V, regardless of the state of SELV.
Connect MODE to VL to enable the linear regulator.
Connect MODE to GND to put the device into shutdown. RSETI sets the maximum output current.
AC
ADAPTER
4.1V 1-CELL Li+ OR
4.5V 3-CELL NiMH/NiCd
4.75V TO 6.5V
IN
1µF
BATT
10µF
INP
4.5V TO 6.5V
MAX1501
1µF
GLED
4V
IN
BATT
INP
GLED
MAX1501
RLED
VI/O
100kΩ
µP
2.8kΩ
10µF
RLED
VL
VL
ACOK
FULLI
FULLI
CHGEN
CHGEN
TMAX
TEMP
MODE
MODE
SELV
TMAX
SETI
TEMP
ON
OFF
ACOK
SELV
SETI
GND GND
CURRENT-LIMIT
ADJUST
GND
GND
UP TO 1.4A
Figure 8. µP-Based Single Li+/3-Cell NiMH/NiCd Battery
Charger
Figure 9. Input Overvoltage-Protected and Current-Limited
Low-Dropout Linear Regulator
______________________________________________________________________________________
13
MAX1501
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
5V
3kΩ
4.1kΩ
5.1kΩ
200kΩ
3kΩ
IN
100kΩ
MAX1501
CHGEN
1kΩ
5V
2.24kΩ
GND
3kΩ
100kΩ
RT = 10kΩ
AT +25°C
10kΩ
3.66kΩ
1kΩ
TBATT
RT
0°C
27.28kΩ
+25°C
+50°C
10.00kΩ
4.16kΩ
Figure 10. Battery Temperature Protection
Figure 10 shows a circuit that adds temperature protection to the battery. Install the thermistor as close to the
battery as possible to ensure accurate temperature measurement. The output of this circuit is logic high when the
battery temperature is less than 0°C and greater than
+50°C. Driving CHGEN high disables the charger.
Chip Information
TRANSISTOR COUNT: 5717
PROCESS: BiCMOS
Layout and Bypassing
RLED
SELV
GND
Pin Configuration
GLED
16
15
14
13
INP
1
12 BATT
IN
2
11 ACOK
GND
3
SETI
4
MAX1501
10 CHGEN
**EXPOSED PADDLE
6
7
8
FULLI
TEMP
VL
5
9
TMAX
Connect IN and INP together as close to the device as
possible and bypass with a 1µF ceramic capacitor.
Bypass BATT to GND with a 10µF ceramic capacitor.
Provide a large copper GND plane to allow the exposed
paddle to sink heat away from the device. Connect the
battery to BATT as close to the device as possible to
provide the most accurate battery voltage sensing.
Make all high-current traces short and wide to minimize
voltage drops.
5mm x 5mm
THIN QFN
**CONNECT EXPOSED PADDLE TO GND
14
______________________________________________________________________________________
MODE
Highly Integrated, Linear Battery Charger with
Thermal Regulation for Portable Applications
b
CL
0.10 M C A B
D2/2
D/2
PIN # 1
I.D.
QFN THIN.EPS
D2
0.15 C A
D
k
0.15 C B
PIN # 1 I.D.
0.35x45
E/2
E2/2
CL
(NE-1) X e
E
E2
k
L
DETAIL A
e
(ND-1) X e
CL
CL
L
L
e
e
0.10 C
A
C
0.08 C
A1 A3
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE
16, 20, 28, 32L, QFN THIN, 5x5x0.8 mm
APPROVAL
COMMON DIMENSIONS
DOCUMENT CONTROL NO.
REV.
21-0140
C
1
2
EXPOSED PAD VARIATIONS
NOTES:
1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994.
2. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES.
3. N IS THE TOTAL NUMBER OF TERMINALS.
4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JESD 95-1
SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE
ZONE INDICATED. THE TERMINAL #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE.
5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.25 mm AND 0.30 mm
FROM TERMINAL TIP.
6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY.
7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION.
8. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.
9. DRAWING CONFORMS TO JEDEC MO220.
10. WARPAGE SHALL NOT EXCEED 0.10 mm.
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE
16, 20, 28, 32L, QFN THIN, 5x5x0.8 mm
APPROVAL
DOCUMENT CONTROL NO.
REV.
21-0140
C
2
2
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15
© 2003 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX1501
Package Information
(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.)