Maxim MAX1908ETI, MAX8724ETI, MAX8765AETI, MAX8765ETI Schematics
AVAILABLE
EVALUATION KIT AVAILABLE
For pricing, delivery, and
ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
General Description
The MAX1908/MAX8724/MAX8765/MAX8765A highly
integrated, multichemistry battery-charger control ICs
simplify the construction of accurate and efficient chargers. These devices use analog inputs to control charge
current and voltage, and can be programmed by the host
or hardwired. The MAX1908/MAX8724/MAX8765/
MAX8765A achieve high efficiency using a buck topology
with synchronous rectification.
The MAX1908/MAX8724/MAX8765/MAX8765A feature
input current limiting. This feature reduces battery
charge current when the input current limit is reached
to avoid overloading the AC adapter when supplying
the load and the battery charger simultaneously. The
MAX1908/MAX8724/MAX8765/MAX8765A provide outputs to monitor current drawn from the AC adapter (DC
input source), battery-charging current, and the presence of an AC adapter. The MAX1908’s conditioning
charge feature provides 300mA to safely charge deeply
discharged lithium-ion (Li+) battery packs.
The MAX1908 includes a conditioning charge feature
while the MAX8724/MAX8765/MAX8765A do not.
The MAX1908/MAX8724/MAX8765/MAX8765A charge two
to four series Li+ cells, providing more than 5A, and are
available in a space-saving, 28-pin, thin QFN package (5mm
× 5mm). An evaluation kit is available to speed designs.
Applications
Notebook and Subnotebook Computers
Personal Digital Assistants
Handheld Terminals
Features
o ±0.5% Output Voltage Accuracy Using Internal
Reference (±0.4% for MAX8765A, 2-/3-Cell Only)
o ±4% Accurate Input Current Limiting
o ±5% Accurate Charge Current
o Analog Inputs Control Charge Current and
Charge Voltage
o Outputs for Monitoring
Current Drawn from AC Adapter
Charging Current
AC Adapter Presence
o Up to 17.6V Battery-Voltage Set Point
o Maximum 28V Input Voltage
o > 95% Efficiency
o Shutdown Control Input
o Charge Any Battery Chemistry
Li+, NiCd, NiMH, Lead Acid, etc.
Low-Cost Multichemistry Battery Chargers
Pin Configuration
Ordering Information
MAX1908
MAX8724
MAX8765
MAX8765A
AC ADAPTER
INPUT
TO EXTERNAL
LOAD
LDO
FROM HOST µP
10µH
0.015Ω
BATT+
DCIN
REFIN
VCTL
ICTL
ACIN
ACOK
SHDN
ICHG
IINP
CCV
CCI
CCS
CELLS
LDO
BST
DLOV
DHI
LX
DLO
PGND
CSIP
CSIN
BATT
REF CLS
GND
CSSP CSSN
0.01Ω
Minimum Operating Circuit
+
Denotes a lead(Pb)-free/RoHS-compliant package.
*
EP = Exposed pad.
MAX1908/MAX8724/
MAX8765/MAX8765A
PART TEMP RANGE PIN-PACKAGE
MAX1908ETI+ -40°C to +85°C 28 Thin QFN-EP*
MAX8724ETI+ -40°C to +85°C 28 Thin QFN-EP*
MAX8765ETI+ -40°C to +85°C 28 Thin QFN-EP*
MAX8765AETI+ -40°C to +85°C 28 Thin QFN-EP*
TOP VIEW
VCTL
BATT
CELLS
CSIN
CSIP
PGND
DLO
15161718192021
22
DLOV
BST
DHI
CSSN
CSSP
IINP
23
LX
24
25
26
27
28
14
GND
13
ICTL
REFIN
12
MAX1908
MAX8724
MAX8765
MAX8765A
+
REF
CLS
DCIN
LDO
THIN QFN
CCS
11
ACOK
ACIN
10
9
ICHG
SHDN
8
7654321
CCI
CCV
19-2764; Rev 5; 11/09
Low-Cost Multichemistry Battery Chargers
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
DCIN
= V
CSSP
= V
CSSN
= 18V, V
BATT
= V
CSIP
= V
CSIN
= 12V, V
REFIN
= 3V, V
VCTL
= V
ICTL
= 0.75 x V
REFIN
, CELLS = open, CLS =
REF, V
BST
- VLX= 4.5V, ACIN = GND = PGND = 0, C
LDO
= 1µF, LDO = DLOV, C
REF
= 1µF; CCI, CCS, and CCV are compensated
per Figure 1a; T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°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.
DCIN, CSSP, CSSN, ACOK to GND.......................-0.3V to +30V
BST to GND ............................................................-0.3V to +36V
BST to LX..................................................................-0.3V to +6V
DHI to LX...................................................-0.3V to (V
BST
+ 0.3V)
LX to GND .................................................................-6V to +30V
BATT, CSIP, CSIN to GND .....................................-0.3V to +20V
CSIP to CSIN or CSSP to CSSN or
PGND to GND ....................................................-0.3V to +0.3V
CCI, CCS, CCV, DLO, ICHG,
IINP, ACIN, REF to GND.......................-0.3V to (V
LDO
+ 0.3V)
DLOV, VCTL, ICTL, REFIN, CELLS, CLS,
LDO, SHDN to GND .............................................-0.3V to +6V
DLOV to LDO.........................................................-0.3V to +0.3V
DLO to PGND .........................................-0.3V to (V
DLOV
+ 0.3V)
LDO Short-Circuit Current...................................................50mA
Continuous Power Dissipation (T
A
= +70°C)
28-Pin Thin QFN (5mm × 5mm)
(derate 20.8mW/°C above +70°C) .........................1666.7mW
Operating Temperature Range ..........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
MAX1908/MAX8724/MAX8765/MAX8765A
2
Maxim Integrated
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CHARGE-VOLTAGE REGULATION
V
Battery-Regulation Voltage
Accuracy
(MAX1908/MAX8724/MAX8765
(2, 3, or 4 Cells) and MAX8765A
(4 Cells Only))
Battery-Regulation Voltage
Accuracy (MAX8765A, 2 or 3
Cells Only)
VCTL Default Threshold V
= V
V
V
V
V
V
VCTL
VCTL
VCTL
VCTL
VCTL
VCTL
VCTL
REFIN
= V
REFIN
= V
LDO
= V
REFIN
= V
REFIN
= V
LDO
rising 4.0 4.1 4.2 V
REFIN Range (Note 1) 2.5 3.6 V
REFIN Undervoltage Lockout V
falling 1.20 1.92 V
REFIN
CHARGE-CURRENT REGULATION
CSIP-to-CSIN Full-Scale Current-
Sense Voltage
Charging-Current Accuracy
V
V
V
V
ICTL
ICTL
ICTL
ICTL
= V
= V
= V
= V
REFIN
REFIN
REFIN
LDO
MAX8765/MAX8765A only; V
0.036
MAX8724 only; V
Charge-Current Gain Error
(MAX8765/MAX8765A Only)
Charge-Current Offset
(MAX8765/MAX8765A Only)
ICTL Default Threshold V
BATT/CSIP/CSIN Input Voltage
Range
-2 +2 %
-2 +2 mV
rising 4.0 4.1 4.2 V
ICTL
0 19 V
-0.5 +0.5
/20 -0.5 +0.5
-0.5 +0.5
-0.4 +0.4
/20 -0.4
-0.4
+0.4
+0.4
71.25 75 78.75 mV
-5 +5
x 0.6 -5 +5
-6 +6
ICTL
= V
= V
ICTL
x 0.058 -33 +33
REFIN
REFIN
x
-45 +45
%
%
%
Low-Cost Multichemistry Battery Chargers
ELECTRICAL CHARACTERISTICS (continued)
(V
DCIN
= V
CSSP
= V
CSSN
= 18V, V
BATT
= V
CSIP
= V
CSIN
= 12V, V
REFIN
= 3V, V
VCTL
= V
ICTL
= 0.75 x V
REFIN
, CELLS = open, CLS =
REF, V
BST
- VLX= 4.5V, ACIN = GND = PGND = 0, C
LDO
= 1µF, LDO = DLOV, C
REF
= 1µF; CCI, CCS, and CCV are compensated
per Figure 1a; T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
Maxim Integrated
3
MAX1908/MAX8724/MAX8765/MAX8765A
CSIP/CSIN Input Current
Cycle-by-Cycle Maximum Current
Limit
ICTL Power-Down Mode
Threshold Voltage
(MAX1908/MAX8724 Only)
ICTL, VCTL Input Bias Current
REFIN Input Bias Current
ICHG Transconductance
(MAX1908/MAX8724 Only)
ICHG Transconductance
(MAX8765/MAX8765A Only)
ICHG Transconductance Error
(MAX8765/MAX8765A Only)
ICHG Transconductance Offset
(MAX8765/MAX8765A Only)
ICHG Output Current V
ICHG Output Voltage V
INPUT-CURRENT REGULATION
CSSP-to-CSSN Full-Scale
Current-Sense Voltage
Input Current-Limit Accuracy
Input Current-Limit Gain Error
(MAX8765/MAX8765A Only)
Input Current-Limit Offset
(MAX8765/MAX8765A Only)
CSSP, CSSN Input Voltage
Range
CSSP, CSSN Input Current
(MAX1908/MAX8724 Only)
CSSP Input Current
(MAX8765/MAX8765A Only)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V
Charging 400
DCIN
= 0V or V
ICTL
RS2 = 0.015mΩ 6.0 6.8 7.5
V
G
ICHG VCSIP
G
ICHG VCSIP
rising
VCTL
V
VCTL
V
DCIN
V
DCIN
V
REFIN
= V
= 0V, V
= 5V, V
- V
- V
= 0 or 3V -1 +1
ICTL
VCTL
REFIN
= 5V -1 +1
= 45mV 2.7 3 3.3 µA/mV
CSIN
= 45mV 2.85 3 3.15 µA/mV
CSIN
-5 +5 %
-5 +5 µA
V
- V
= 75mV -6 +6
CSIN
- V
= 45mV -5 +5 ICHG Accuracy
CSIN
- V
= 5mV -40 +40
CSIN
- V
= 150mV, V
CSIN
- V
= 150mV, ICHG = open 3.5 V
CSIN
V
V
CSIP
CSIP
CSIP
CSIP
CSIP
72 75 78 mV
V
= V
CLS
REF
V
= V
/2 -7.5 +7.5
REF
= 1.1V (MAX8765/MAX8765A only) -10 +10
V
CLS
CLS
-2 +2 %
-2 +2 mV
8 28 V
V
= 0V 0.1 1
V
DCIN
V
CSSP
CSSP
= V
= V
CSSN
CSSN
= V
= 28V
= 0V or V
= V
= V
ICTL
= 3V -1 +1
ICHG
= 0V
SHDN
REFIN
= 0V 350 µA
1
REFIN/
= 5V -1 +1
REFIN/55 REFIN/
100
-4 +4
> 8V 350 600
DCIN
V
= 0V 0.1 1
DCIN
= 28V
V
DCIN
400 650
650
33
µA
A
V
µA
µA
%
%
µA
µA
Low-Cost Multichemistry Battery Chargers
ELECTRICAL CHARACTERISTICS (continued)
(V
DCIN
= V
CSSP
= V
CSSN
= 18V, V
BATT
= V
CSIP
= V
CSIN
= 12V, V
REFIN
= 3V, V
VCTL
= V
ICTL
= 0.75 x V
REFIN
, CELLS = open, CLS =
REF, V
BST
- VLX= 4.5V, ACIN = GND = PGND = 0, C
LDO
= 1µF, LDO = DLOV, C
REF
= 1µF; CCI, CCS, and CCV are compensated
per Figure 1a; T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
MAX1908/MAX8724/MAX8765/MAX8765A
4
Maxim Integrated
CSSN Input Current
(MAX8765/MAX8765A Only)
CLS Input Range
(MAX1908/MAX8724 Only)
CLS Input Range
(MAX8765/MAX8765A Only)
CLS Input Bias Current V
IINP Transconductance
(MAX1908/MAX8724 Only)
IINP Accuracy
IINP Transconductance
(MAX8765/MAX8765A Only)
IINP Transconductance Error
(MAX8765/MAX8765A Only)
IINP Transconductance Offset
(MAX8765/MAX8765A Only)
IINP Output Current V
IINP Output Voltage V
SUPPLY AND LDO REGULATOR
DCIN Input Voltage Range V
DCIN Undervoltage-Lockout Trip
Point
DCIN Quiescent Current I
BATT Input Current I
LDO Output Voltage 8V < V
LDO Load Regulation 0 < I
LDO Undervoltage-Lockout Trip
Point
REFERENCE
REF Output Voltage 0 < I
REF Undervoltage-Lockout Trip
Point
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V
CSSP
= V
= 28V
CSSN
V
= 0V 0.1 1
DCIN
V
= 28V 0.1 1
DCIN
1.6 REF V
1.1 REF V
= 2V -1 +1 µA
CLS
G
IINP VCSSP
G
IINP VCSSP
V
CSSP
V
CSSP
- V
- V
- V
- V
= 75mV 2.7 3 3.3 µA/mV
CSSN
= 75mV -5 +5
CSSN
= 37.5mV -7.5 +7.5
CSSN
= 75mV 2.82 3 3.18 µA/mV
CCSN
-6 +6 %
-10 +10 µA
- V
DCIN
DCIN
BATT
V
V
- V
CSSN
CSSN
= 150mV, V
= 150mV, V
CSSP
CSSP
8 28 V
V
falling 7 7.4
DCIN
V
rising 7.5 7.85
DCIN
8.0V < V
V
BATT
V
BATT
LDO
DCIN
REF
falling 3.1 3.9 V
REF
< 28V 3.2 6 mA
DCIN
= 19V, V
= 2V to 19V, V
< 28V, no load 5.25 5.4 5.55 V
DCIN
< 10mA 34 100 mV
= 8V 3.20 4 5.15 V
< 500µA 4.072 4.096 4.120 V
= 0V 1
DCIN
DCIN
= 0V 350 µA
IINP
= open 3.5 V
IINP
= 19.3V 200 500
µA
%
V
µA
Low-Cost Multichemistry Battery Chargers
ELECTRICAL CHARACTERISTICS (continued)
(V
DCIN
= V
CSSP
= V
CSSN
= 18V, V
BATT
= V
CSIP
= V
CSIN
= 12V, V
REFIN
= 3V, V
VCTL
= V
ICTL
= 0.75 x V
REFIN
, CELLS = open, CLS =
REF, V
BST
- VLX= 4.5V, ACIN = GND = PGND = 0, C
LDO
= 1µF, LDO = DLOV, C
REF
= 1µF; CCI, CCS, and CCV are compensated
per Figure 1a; T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
Maxim Integrated
5
MAX1908/MAX8724/MAX8765/MAX8765A
TRIP POINTS
BATT Power-Fail Threshold
BATT Power-Fail Threshold
Hysteresis
ACIN Threshold
ACIN Threshold Hysteresis 0.5% of REF 20 mV
ACIN Input Bias Current V
SWITCHING REGULATOR
DHI Off-Time
DHI Minimum Off-Time
DHI Maximum On-Time 2.5 5 7.5 ms
DLOV Supply Current DLO low 5 10 µA
BST Supply Current DHI high 6 15 µA
BST Input Quiescent Current
LX Input Bias Current V
LX Input Quiescent Current V
DHI Maximum Duty Cycle 99 99.9 %
Minimum Discontinuous-Mode
Ripple Current
Battery Undervoltage Charge
Current
Battery Undervoltage Current
Threshold
DHI On-Resistance High V
DHI On-Resistance Low V
DLO On-Resistance High V
DLO On-Resistance Low V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V
(MAX1908/MAX8724 only)
V
(MAX8765/MAX8765A only)
falling, referred to V
DCIN
falling, referred to V
CSSP
CSIN
CSIN
50 100 150
50 100 150
200 mV
ACIN rising (MAX8765/MAX8765A only) 2.028 2.048 2.068
ACIN rising (MAX1908/MAX8724 only) 2.007 2.048 2.089
= 2.048V -1 +1 µA
ACIN
V
BATT
V
CELLS
V
BATT
V
CELLS
V
DCIN
V
BATT
DCIN
DCIN
= 16V, V
= V
REFIN
= 16V, V
= V
REFIN
= 0V, V
= V
LX
= 28V, V
= 0V, V
DCIN
DCIN
BST
= 20V
BATT
BATT
= 19V,
= 17V,
= 24.5V,
= V
LX
= V
LX
0.36 0.4 0.44 µs
0.24 0.28 0.33 µs
0.3 1 µA
= 20V
= 20V 0.3 1 µA
150 500 µA
0.5 A
V
= 3V per cell (RS2 = 15mΩ),
BATT
MAX1908 only, V
BATT
rising
CELLS = GND, MAX1908 only, V
CELLS = open, MAX1908 only, V
CELLS = V
- VLX = 4.5V, I
BST
- V
BST
LX
= 4.5V, I
DLOV
= 4.5V, I
DLOV
, MAX1908 only, V
REFIN
DHI
= 4.5V, I
DHI
= +100mA 4 7 Ω
DLO
= -100mA 1 3.5 Ω
DLO
= +100mA 4 7 Ω
= -100mA 1 3.5 Ω
150 300 450 mA
rising 6.1 6.2 6.3
BATT
rising
BATT
rising 12.2 12.4 12.6
BATT
9.15 9.3 9.45
mV
V
V
Low-Cost Multichemistry Battery Chargers
ELECTRICAL CHARACTERISTICS (continued)
(V
DCIN
= V
CSSP
= V
CSSN
= 18V, V
BATT
= V
CSIP
= V
CSIN
= 12V, V
REFIN
= 3V, V
VCTL
= V
ICTL
= 0.75 x V
REFIN
, CELLS = open, CLS =
REF, V
BST
- VLX= 4.5V, ACIN = GND = PGND = 0, C
LDO
= 1µF, LDO = DLOV, C
REF
= 1µF; CCI, CCS, and CCV are compensated
per Figure 1a; T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
MAX1908/MAX8724/MAX8765/MAX8765A
6
Maxim Integrated
ERROR AMPLIFIERS
GMV Amplifier Transconductance GMV
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V
= V
V C T L
C E LLS = V
, V
LD O
RE F IN
BAT T
= 16.8V ,
0.0625 0.125 0.2500 µA/mV
GMI Amplifier Transconductance GMI V
GMS Amplifier Transconductance GMS V
CCI, CCS, CCV Clamp Voltage 0.25V < V
ICTL
CLS
= V
RE F IN
= V
REF
CCV,CCS,CCI
, V
, V
CSIP
CSSP
- V
- V
= 75mV 0.5 1 2.0 µA/mV
CSIN
= 75mV 0.5 1 2.0 µA/mV
CSSN
< 2V 150 300 600 mV
LOGIC LEVELS
CELLS Input Low Voltage 0.4 V
CELLS Input Open Voltage CELLS = open
CELLS Input High Voltage
CELLS Input Bias Current CELLS = 0V or V
RE F IN
(V
REFIN
/2) -
0.2V
V
- 0.4V
V
REFIN
-2 +2 µA
( V
R E F IN
/
R E F IN
/2) +
2
0.2V
V
ACOK AND SHDN
ACOK Input Voltage Range 0 28 V
ACOK Sink Current V
ACOK Leakage Current V
A COK
A COK
= 0.4V, V
= 28V, V
= 3V 1 mA
ACIN
= 0V 1 µA
ACIN
SHDN Input Voltage Range 0 LDO V
V
SHDN
= 0V OR V
LDO
-1 +1
SHDN Input Bias Current
V
SHDN
= 0V OR V
= 5V -1 +1
SHDN
V
µA
SHDN Threshold V
falling 22 23.5 25
S HDN
SHDN Threshold Hysteresis 1
% of
V
REFIN
% of
V
REFIN
ELECTRICAL CHARACTERISTICS
(V
DCIN
= V
CSSP
= V
CSSN
= 18V, V
BATT
= V
CSIP
= V
CSIN
= 12V, V
REFIN
= 3V, V
VCTL
= V
ICTL
= 0.75 x V
REFIN
, CELLS = open, CLS =
REF, V
BST
- VLX= 4.5V, ACIN = GND = PGND = 0, C
LDO
= 1µF, LDO = DLOV, C
REF
= 1µF; CCI, CCS, and CCV are compensated
per Figure 1a; T
A
= -40°C to +85°C, unless otherwise noted.) (Note 2)
Low-Cost Multichemistry Battery Chargers
Maxim Integrated
7
MAX1908/MAX8724/MAX8765/MAX8765A
CHARGE-VOLTAGE REGULATION
Battery Regulation Voltage
Accuracy (2, 3, or 4 Cells)
REFIN Range (Note 1) 2.5 3.6 V
REFIN Undervoltage Lockout V
CHARGE CURRENT REGULATION
CSIP-to-CSIN Full-Scale Current-
Sense Voltage
Charging-Current Accuracy
Charge-Current Gain Error
(MAX8765/MAX8765A Only)
Charge-Current Offset
(MAX8765/MAX8765A Only)
BATT/CSIP/CSIN Input Voltage
Range
CSIP/CSIN Input Current
Cycle-by-Cycle Maximum Current
Limit
ICTL Power-Down Mode
Threshold Voltage
(MAX1908/MAX8724 Only)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V
V
V
V
V
V
V
= V
VCTL
VCTL
VCTL
REFIN
ICTL
ICTL
ICTL
ICTL
REFIN
= V
REFIN
= V
LDO
falling 1.92 V
= V
REFIN
= V
REFIN
= V
= V
x 0.6 -7.5 +7.5
REFIN
LDO
MAX8765/MAX8765A only; V
0.036
MAX8724 only;
V
ICTL
= V
REFIN
x 0.058
-0.6 +0.6
/20 -0.6 +0.6
-0.6 +0.6
70.5 79.5 mV
-6 +6
-7.5 +7.5
ICTL
= V
REFIN
x
-50 +50
-33 +33
-2 +2 %
-2 +2 mV
0 19 V
V
I
MAX
V
= 0V or V
DCIN
Charging 650
RS2 = 0.015Ω 6.0 7.5 A
rising
ICTL
ICTL
= 0V or V
= 0V 1
SHDN
REFIN/
100
REFIN/
33
%
%
µA
V
ICHG Transconductance
(MAX1908/MAX8724 Only)
ICHG Transconductance
(MAX8765/MAX8765A Only)
ICHG Transconductance Error
(MAX8765/MAX8765A Only)
ICHG Transconductance Offset
(MAX8765/MAX8765A Only)
G
ICHG VCSIP
G
ICHG VCSIP
- V
= 45mV 2.7 3.3 µA/mV
CSIN
- V
= 45mV 2.785 3.225 µA/mV
CSIN
-7.5 +7.5 %
-6.5 +6.5 µA
Low-Cost Multichemistry Battery Chargers
ELECTRICAL CHARACTERISTICS (continued)
(V
DCIN
= V
CSSP
= V
CSSN
= 18V, V
BATT
= V
CSIP
= V
CSIN
= 12V, V
REFIN
= 3V, V
VCTL
= V
ICTL
= 0.75 x V
REFIN
, CELLS = open, CLS =
REF, V
BST
- VLX= 4.5V, ACIN = GND = PGND = 0, C
LDO
= 1µF, LDO = DLOV, C
REF
= 1µF; CCI, CCS, and CCV are compensated
per Figure 1a; T
A
= -40°C to +85°C, unless otherwise noted.) (Note 2)
MAX1908/MAX8724/MAX8765/MAX8765A
8
Maxim Integrated
ICHG Accuracy
INPUT-CURRENT REGULATION
CSSP-to-CSSN Full-Scale
Current-Sense Voltage
Input Current-Limit Accuracy
Input Current-Limit Gain Error
(MAX8765/MAX8765A Only)
Input Current-Limit Offset
(MAX8765/MAX8765A Only)
CSSP, CSSN Input Voltage
Range
CSSP, CSSN Input Current
(MAX1908/MAX8724 Only)
CSSP Input Current
(MAX8765/MAX8765A Only)
CSSN Input Current
(MAX8765/MAX8765A Only)
CLS Input Range
(MAX1908/MAX8724 Only)
CLS Input Range
(MAX8765/MAX8765A Only)
IINP Transconductance
(MAX1908/MAX8724 Only)
IINP Transconductance
(MAX8765/MAX8765A Only)
IINP Transconductance Error
(MAX8765/MAX8765A Only)
IINP Transconductance Offset
(MAX8765/MAX8765A Only)
IINP Accuracy
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V
V
V
CSIP
CSIP
CSIP
- V
- V
- V
= 75mV -7.5 +7.5
CSIN
= 45mV -7.5 +7.5
CSIN
= 5mV -40 +40
CSIN
71.25 78.75 mV
V
= V
CLS
REF
V
= V
/2 -7.5 +7.5
REF
= 1.1V (MAX8765/MAX8765A only) -10 +10
V
CLS
CLS
-5 +5
-2 +2 %
-2 +2 mV
8 28 V
V
= 0V 1
V
V
DCIN
V
CSSP
CSSP
CSSP
= V
= V
= V
CSSN
CSSN
CSSN
= V
DCIN
= 28V
= 28V
> 8V 600
V
= 0V 1
DCIN
V
= 28V 650
DCIN
V
= 0V 1
DCIN
V
= 28V 1
DCIN
1.6 REF V
1.1 REF V
G
IINP VCSSP
G
IINP VCSSP
- V
- V
= 75mV 2.7 3.3 µA/mV
CSSN
= 75mV 2.785 3.225 µA/mV
CCSN
-7.5 +7.5 %
-12 +12 µA
V
- V
CSSP
V
CSSP
= 75mV -7.5 +7.5
CSSN
- V
= 37.5mV -7.5 +7.5
CSSN
%
%
µA
µA
µA
%
Low-Cost Multichemistry Battery Chargers
ELECTRICAL CHARACTERISTICS (continued)
(V
DCIN
= V
CSSP
= V
CSSN
= 18V, V
BATT
= V
CSIP
= V
CSIN
= 12V, V
REFIN
= 3V, V
VCTL
= V
ICTL
= 0.75 x V
REFIN
, CELLS = open, CLS =
REF, V
BST
- VLX= 4.5V, ACIN = GND = PGND = 0, C
LDO
= 1µF, LDO = DLOV, C
REF
= 1µF; CCI, CCS, and CCV are compensated
per Figure 1a; T
A
= -40°C to +85°C, unless otherwise noted.) (Note 2)
Maxim Integrated
9
MAX1908/MAX8724/MAX8765/MAX8765A
SUPPLY AND LDO REGULATOR
DCIN Input Voltage Range V
DCIN Quiescent Current I
BATT Input Current I
LDO Output Voltage 8V < V
LDO Load Regulation 0 < I
REFERENCE
REF Output Voltage 0 < I
TRIP POINTS
BATT Power-Fail Threshold
ACIN Threshold
SWITCHING REGULATOR
DHI Off-Time
DHI Minimum Off-Time
DHI Maximum On-Time 2.5 7.5 ms
DHI Maximum Duty Cycle 99 %
Battery Undervoltage Charge
Current
Battery Undervoltage Current
Threshold
DHI On-Resistance High V
DHI On-Resistance Low V
DLO On-Resistance High V
DLO On-Resistance Low V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DCIN
DCIN
BATT
8 28 V
8.0V < V
V
BATT
V
BATT
LDO
REF
V
DCIN
(MAX1908/MAX8724 only)
V
CSSP
(MAX8765/MAX8765A only)
ACIN rising (
ACIN rising (MAX1908/MAX8724 only) 2.007 2.089
V
BATT
V
CELLS
V
BATT
V
CELLS
V
BATT
MAX1908 only, V
CELLS = GND, MAX1908 only, V
CELLS = open, MAX1908 only, V
CELLS = V
- VLX = 4.5V, I
BST
- VLX = 4.5V, I
BST
DLOV
DLOV
< 28V 6 mA
DCIN
= 19V, V
= 2V to 19V, V
< 28V, no load 5.25 5.55 V
DCIN
< 10mA 100 mV
< 500µA 4.065 4.120 V
falling, referred to V
falling, referred to V
= 16V, V
= V
REFIN
= 16V, V
= V
REFIN
= 3V per cell (RS2 = 15mΩ),
REFIN
= 4.5V, I
= 4.5V, I
= 0V 1
DCIN
= 19.3V 500
DCIN
CSIN
CSIN
MAX8765/MAX8765A
= 19V,
DCIN
= 17V,
DCIN
rising
BATT
, MAX1908 only, V
= +100mA 7 Ω
DHI
= -100mA 3.5 Ω
DHI
= +100mA 7 Ω
DLO
= -100mA 3.5 Ω
DLO
only) 2.028 2.068
rising 6.09 6.30
BATT
rising 9.12 9.45
BATT
rising 12.18 12.60
BATT
50 150
50 150
0.35 0.45 µs
0.24 0.33 µs
150 450 mA
µA
mV
V
V
Low-Cost Multichemistry Battery Chargers
ELECTRICAL CHARACTERISTICS (continued)
(V
DCIN
= V
CSSP
= V
CSSN
= 18V, V
BATT
= V
CSIP
= V
CSIN
= 12V, V
REFIN
= 3V, V
VCTL
= V
ICTL
= 0.75 x V
REFIN
, CELLS = open, CLS =
REF, V
BST
- VLX= 4.5V, ACIN = GND = PGND = 0, C
LDO
= 1µF, LDO = DLOV, C
REF
= 1µF; CCI, CCS, and CCV are compensated
per Figure 1a; T
A
= -40°C to +85°C, unless otherwise noted.) (Note 2)
Note 1: If both ICTL and VCTL use default mode (connected to LDO), REFIN is not used and can be connected to LDO.
Note 2: Specifications to T
A
= -40°C are guaranteed by design and not production tested.
LOAD-TRANSIENT RESPONSE
(BATTERY INSERTION AND REMOVAL)
MAX1908 toc01
1ms/div
I
BATT
2A/div
V
BATT
5V/div
V
CCI
500mV/div
V
CCV
500mV/div
ICTL = LDO
VCTL = LDO
CCV
CCI
LOAD-TRANSIENT RESPONSE
(STEP IN-LOAD CURRENT)
MAX1908 toc02
1ms/div
V
BATT
2V/div
V
CCI
500mV/div
V
CCS
500mV/div
16.8V
0
0
LOAD
CURRENT
5A/div
ADAPTER
CURRENT
5A/div
ICTL = LDO
CHARGING CURRENT = 3A
V
BATT
= 16.8V
LOAD STEP = 0 TO 4A
I
SOURCE
LIMIT = 5A
CCS
CCS
CCI
CCI
V
BATT
2V/div
0
0
0
CHARGE
CURRENT
2A/div
LOAD
CURRENT
5A/div
ADAPTER
CURRENT
5A/div
LOAD-TRANSIENT RESPONSE
(STEP IN-LOAD CURRENT)
MAX1908 toc03
1ms/div
ICTL = LDO
CHARGING CURRENT = 3A
V
BATT
= 16.8V
LOAD STEP = 0 TO 4A
I
SOURCE
LIMIT = 5A
Typical Operating Characteristics
(Circuit of Figure 1, V
DCIN
= 20V, TA= +25°C, unless otherwise noted.)
MAX1908/MAX8724/MAX8765/MAX8765A
10
Maxim Integrated
ERROR AMPLIFIERS
GMV Amplifier Transconductance GMV
GMI Amplifier Transconductance GMI V
GMS Amplifier Transconductance GMS V
CCI, CCS, CCV Clamp Voltage 0.25V < V
LOGIC LEVELS
CELLS Input Low Voltage 0.4 V
CELLS Input Open Voltage CELLS = open
CELLS Input High Voltage
ACOK AND SHDN
ACOK Input Voltage Range 0 28 V
ACOK Sink Current V
SHDN Input Voltage Range 0 LDO V
SHDN Threshold V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V
= V
, V
, V
= 16.8V ,
BAT T
, V
CSSP
CSIP
- V
- V
= 75mV 0.5 2.0 µA/mV
CSIN
= 75mV 0.5 2.0 µA/mV
CSSN
0.0625 0.250 µA/mV
< 2V 150 600 mV
(V
REFIN
/2) -
0.2V
V
REFIN
- 0.4V
= 3V 1 mA
ACIN
V
( V
/2) +
0.2V
R E F IN
V C T L
C E LLS = V
ICTL
CLS
ACOK
SHDN
LD O
RE F IN
= V
RE F IN
= V
REF
CCV,CCS,CCI
= 0.4V, V
falling 22 25
% of
V
REFIN
V
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