MAXIM MAX1908, MAX8724, MAX8765 Technical data
General Description
The MAX1908/MAX8724/MAX8765 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 achieve high efficiency
using a buck topology with synchronous rectification.
The MAX1908/MAX8724/MAX8765 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 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 do not.
The MAX1908/MAX8724/MAX8765 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
♦ ±0.5% Output Voltage Accuracy Using Internal
Reference (0°C to +85°C)
♦ ±4% Accurate Input Current Limiting
♦ ±5% Accurate Charge Current
♦ Analog Inputs Control Charge Current and
Charge Voltage
♦ Outputs for Monitoring
Current Drawn from AC Adapter
Charging Current
AC Adapter Presence
♦ Up to 17.6V Battery-Voltage Set Point
♦ Maximum 28V Input Voltage
♦ > 95% Efficiency
♦ Shutdown Control Input
♦ Charge Any Battery Chemistry
Li+, NiCd, NiMH, Lead Acid, etc.
MAX1908/MAX8724/MAX8765
Low-Cost Multichemistry Battery Chargers
________________________________________________________________ Maxim Integrated Products 1
28
27
26
25
24
23
22
IINP
CSSP
CSSN
DHI
BST
LX
DLOV
8
9
10
11
12
13
14
SHDN
ICHG
ACIN
ACOK
REFIN
ICTL
GND
15161718192021
VCTL
BATT
CELLS
CSIN
CSIP
PGND
DLO
7654321
CCV
CCI
CCS
REF
CLS
LDO
DCIN
MAX1908
MAX8724
MAX8765
THIN QFN
TOP VIEW
Pin Configuration
Ordering Information
MAX1908
MAX8724
MAX8765
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
19-2764; Rev 4; 7/05
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.
EVALUATION KIT
AVAILABLE
PART
TEMP RANGE
PIN-
PKG CODE
MAX1908ETI
T2855-6
MAX8724ETI
T2855-6
MAX8765ETI
T2855-6
PACKAGE
-40°C to +85°C 28 Thin QFN
-40°C to +85°C 28 Thin QFN
-40°C to +85°C 28 Thin QFN
MAX1908/MAX8724/MAX8765
Low-Cost Multichemistry Battery Chargers
2 _______________________________________________________________________________________
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 = float, 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
PARAMETER
CONDITIONS
UNITS
CHARGE-VOLTAGE REGULATION
V
VCTL
= V
REFIN
(2, 3, or 4 cells)
V
VCTL
= V
REFIN
/ 20 (2, 3, or 4 cells)
Battery-Regulation Voltage
Accuracy
V
VCTL
= V
LDO
(2, 3, or 4 cells)
%
VCTL Default Threshold V
VCTL
rising 4.0 4.1 4.2 V
REFIN Range (Note 1) 2.5 3.6 V
REFIN Undervoltage Lockout V
REFIN
falling
V
CHARGE-CURRENT REGULATION
CSIP-to-CSIN Full-Scale Current-
Sense Voltage
V
ICTL
= V
REFIN
75
mV
V
ICTL
= V
REFIN
-5 +5
V
ICTL
= V
REFIN
x 0.6 -5 +5
V
ICTL
= V
LDO
-6 +6
MAX8765 only; V
ICTL
= V
REFIN
x 0.036 -45
Charging-Current Accuracy
MAX8724 only; V
ICTL
= V
REFIN
x 0.058 -33
%
Charge-Current Gain Error
(MAX8765 Only)
-2 +2 %
Charge-Current Offset
(MAX8765 Only)
-2 +2 mV
ICTL Default Threshold V
ICTL
rising 4.0 4.1 4.2 V
BATT/CSIP/CSIN Input Voltage
Range
0 19 V
V
DCIN
= 0 or V
ICTL
= 0 or SHDN = 0 1
CSIP/CSIN Input Current
Charging
650
µA
SYMBOL
MIN TYP MAX
-0.5
-0.5
-0.5
71.25
1.20 1.92
400
+0.5
+0.5
+0.5
78.75
+45
+33
Low-Cost Multichemistry Battery Chargers
ELECTRICAL CHARACTERISTICS (continued)
(V
= V
DCIN
REF, V
BST
per Figure 1a; T
Cycle-by-Cycle Maximum Current
Limit
= V
CSSP
- VLX= 4.5V, ACIN = GND = PGND = 0, C
A
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
= 18V, V
CSSN
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
BATT
= V
I
MAX
CSIP
= V
= 12V, V
CSIN
LDO
REFIN
= 1µF, LDO = DLOV, C
RS2 = 0.015Ω 6.0 6.8 7.5
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 Only)
ICHG Transconductance Error
(MAX8765 Only)
ICHG Transconductance Offset
(MAX8765 Only)
ICHG Accuracy
ICHG Output Current V
ICHG Output Voltage V
V
G
ICHG VCSIP
G
ICHG VCSIP
rising
ICTL
V
VCTL
V
DCIN
V
DCIN
V
REFIN
= V
= 0, V
= 5V, V
- V
- V
= 0 or 3V -1 +1
ICTL
= V
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
CSIN
- V
= 5mV -40 +40
CSIN
- V
= 150mV, V
CSIN
- V
= 150mV, ICHG = float 3.5 V
CSIN
V
V
CSIP
CSIP
CSIP
CSIP
CSIP
INPUT-CURRENT REGULATION
CSSP-to-CSSN Full-Scale
Current-Sense Voltage
Input Current-Limit Gain Error
(MAX8765 Only)
Input Current-Limit Offset
(MAX8765 Only)
CSSP, CSSN Input Voltage
Range
CSSP, CSSN Input Current
(MAX1908/MAX8724 Only)
CSSP Input Current
(MAX8765 Only)
72 75 78 mV
V
= V
CLS
REF
V
= V
/ 2 -7.5 +7.5 Input Current-Limit Accuracy
REF
= 1.1V (MAX8765 only) -10 +10
V
CLS
CLS
-2 +2 %
-2 +2 mV
8 28 V
V
= 0 0.1 1
V
DCIN
V
CSSP
CSSP
= V
= V
CSSN
CSSN
= V
= 28V
= 3V, V
= V
ICTL
= 3V -1 +1
ICHG
= V
VCTL
REF
= 5V -1 +1
REFIN
= 0 350 µA
= 0.75 x V
ICTL
= 1µF; CCI, CCS, and CCV are compensated
REFIN /
100
, CELLS = float, CLS =
REFIN
REFIN /55 REFIN
/ 33
-4 +4
> 8V 350 600
DCIN
V
= 0V 0.1 1
DCIN
= 28V
V
DCIN
400 650
MAX1908/MAX8724/MAX8765
A
V
µA
µA
%
%
µA
µA
_______________________________________________________________________________________ 3
MAX1908/MAX8724/MAX8765
Low-Cost Multichemistry Battery Chargers
4 _______________________________________________________________________________________
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 = float, 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.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
DCIN
= 0 0.1 1
CSSN Input Current
(MAX8765 Only)
V
CSSP
= V
CSSN
= 28V
V
DCIN
= 28V 0.1 1
µA
CLS Input Range
(MAX1908/MAX8724 Only)
1.6
V
CLS Input Range
(MAX8765 Only)
1.1
V
CLS Input Bias Current V
CLS
= 2V -1 +1 µA
IINP Transconductance
(MAX1908/MAX8724 Only)
G
IINP
V
CSSP
- V
CSSN
= 75mV 2.7 3 3.3
µA/mV
V
CSSP
- V
CSSN
= 75mV -5 +5
IINP Accuracy
V
CSSP
- V
CSSN
= 37.5mV
%
IINP Transconductance
(MAX8765 Only)
G
IINP
V
CSSP
- V
CCSN
= 75mV
3
µA/mV
IINP Transconductance Error
(MAX8765 Only)
-6 +6 %
IINP Transconductance Offset
(MAX8765 Only)
-10
µA
IINP Output Current V
CSSP
- V
CSSN
= 150mV, V
IINP
= 0
µA
IINP Output Voltage V
CSSP
- V
CSSN
= 150mV, V
IINP
= float 3.5 V
SUPPLY AND LDO REGULATOR
DCIN Input Voltage Range V
DCIN
8 28 V
V
DCIN
falling 7 7.4
DCIN Undervoltage-Lockout Trip
Point
V
DCIN
rising 7.5
V
DCIN Quiescent Current I
DCIN
8.0V < V
DCIN
< 28V 3.2 6 mA
V
BATT
= 19V, V
DCIN
= 0 1
BATT Input Current I
BATT
V
BATT
= 2V to 19V, V
DCIN
= 19.3V
500
µA
LDO Output Voltage 8V < V
DCIN
< 28V, no load
5.4
V
LDO Load Regulation 0 < I
LDO
< 10mA
34 100 mV
LDO Undervoltage-Lockout Trip
Point
V
DCIN
= 8V
4
V
REFERENCE
REF Output Voltage 0 < I
REF
< 500µA
V
REF Undervoltage-Lockout Trip
Point
V
REF
falling 3.1 3.9 V
REF
REF
-7.5
2.82
350
5.25
3.20
4.072 4.096 4.120
200
+7.5
3.18
+10
7.85
5.55
5.15
MAX1908/MAX8724/MAX8765
Low-Cost Multichemistry Battery Chargers
_______________________________________________________________________________________ 5
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 = float, 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.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
TRIP POINTS
V
DCIN
falling, referred to V
CSIN
(MAX1908/MAX8724 only)
50
150
BATT Power-Fail Threshold
V
CSSP
falling, referred to V
CSIN
(MAX8765 only)
50
150
mV
BATT Power-Fail Threshold
Hysteresis
mV
ACIN rising (MAX8765 only)
V
ACIN Threshold
ACIN rising (MAX1908/MAX8724 only)
V
ACIN Threshold Hysteresis 0.5% of REF 20 mV
ACIN Input Bias Current V
ACIN
= 2.048V -1 +1 µA
SWITCHING REGULATOR
DHI Off-Time
V
BATT
= 16V, V
DCIN
= 19V,
V
CELLS
= V
REFIN
0.4
µs
DHI Minimum Off-Time
V
BATT
= 16V, V
DCIN
= 17V,
V
CELLS
= V
REFIN
µs
DHI Maximum On-Time 2.5 5 7.5 ms
DLOV Supply Current I
DLOV
DLO low 5 10 µA
BST Supply Current I
BST
DHI high 6 15 µA
BST Input Quiescent Current
V
DCIN
= 0, V
BST
= 24.5V,
V
BATT
= VLX = 20V
0.3 1 µA
LX Input Bias Current V
DCIN
= 28V, V
BATT
= VLX = 20V
500 µA
LX Input Quiescent Current V
DCIN
= 0, V
BATT
= VLX = 20V 0.3 1 µA
DHI Maximum Duty Cycle 99
%
Minimum Discontinuous-Mode
Ripple Current
0.5 A
Battery Undervoltage Charge
Current
V
BATT
= 3V per cell (RS2 = 15mΩ),
MAX1908 only, V
BATT
rising
450 mA
CELLS = GND, MAX1908 only, V
BATT
rising 6.1 6.2 6.3
CELLS = float, MAX1908 only, V
BATT
rising
9.3
Battery Undervoltage Current
Threshold
V
DHI On-Resistance High V
BST
- VLX = 4.5V, I
DHI
= +100mA 4 7 Ω
DHI On-Resistance Low V
BST
- V
LX
= 4.5V, I
DHI
= -100mA 1 3.5 Ω
DLO On-Resistance High V
DLOV
= 4.5V, I
DLO
= +100mA
4 7 Ω
DLO On-Resistance Low V
DLOV
= 4.5V, I
DLO
= -100mA
1 3.5 Ω
100
100
200
2.028 2.048 2.068
2.007 2.048 2.089
0.36
0.24 0.28 0.33
150
99.9
CELLS = V
, MAX1908 only, V
REFIN
BATT
rising 12.2 12.4 12.6
150 300
9.15
0.44
9.45
MAX1908/MAX8724/MAX8765
Low-Cost Multichemistry Battery Chargers
6 _______________________________________________________________________________________
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 = float, 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.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ERROR AMPLIFIERS
GMV Amplifier Transconductance
GMV
V
V C T L
= V
LD O
, V
BAT T
= 16.8V ,
C E LLS = V
RE F IN
µA/mV
GMI Amplifier Transconductance
GMI V
ICTL
= V
RE F IN
, V
CSIP
- V
CSIN
= 75mV 0.5 1 2.0
µA/mV
GMS Amplifier Transconductance
GMS V
CLS
= V
REF
, V
CSSP
- V
CSSN
= 75mV 0.5 1 2.0
µA/mV
CCI, CCS, CCV Clamp Voltage 0.25V < V
CCV,CCS,CCI
< 2V
600 mV
LOGIC LEVELS
CELLS Input Low Voltage 0.4 V
CELLS Input Float Voltage CELLS = float
(V
REFIN
/ 2) -
0.2V
V
REFIN
/ 2
( V
R E F IN
/ 2) +
V
CELLS Input High Voltage
V
REFIN
V
CELLS Input Bias Current CELLS = 0 or V
REFIN
-2 +2 µA
ACOK AND SHDN
ACOK Input Voltage Range 0 28 V
ACOK Sink Current V
ACOK
= 0.4V, V
ACIN
= 3V 1 mA
ACOK Leakage Current V
ACOK
= 28V, V
ACIN
= 0 1 µA
SHDN Input Voltage Range 0
V
V
SHDN
= 0 or V
LDO
-1 +1
SHDN Input Bias Current
V
DCIN
= 0, V
SHDN
= 5V -1 +1
µA
SHDN Threshold V
SHDN
falling 22
25
% of
V
REFIN
SHDN Threshold Hysteresis 1
% of
V
REFIN
0.0625 0.125 0.2500
150 300
- 0.4V
0.2V
23.5
LDO
MAX1908/MAX8724/MAX8765
Low-Cost Multichemistry Battery Chargers
_______________________________________________________________________________________ 7
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 = FLOAT, 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)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
CHARGE-VOLTAGE REGULATION
V
VCTL
= V
REFIN
(2, 3, or 4 cells)
V
VCTL
= V
REFIN
/ 20 (2, 3, or 4 cells)
Battery Regulation Voltage
Accuracy
V
VCTL
= V
LDO
(2, 3, or 4 cells)
%
REFIN Range (Note 1) 2.5 3.6 V
REFIN Undervoltage Lockout V
REFIN
falling
V
CHARGE CURRENT REGULATION
CSIP-to-CSIN Full-Scale Current-
Sense Voltage
V
ICTL
= V
REFIN
mV
V
ICTL
= V
REFIN
-6 +6
V
ICTL
= V
REFIN
x 0.6
V
ICTL
= V
LDO
MAX8765 only; V
ICTL
= V
REFIN
x 0.036 -50
Charging-Current Accuracy
MAX8724 only;
V
ICTL
= V
REFIN
x 0.058
-33
%
Charge-Current Gain Error
(MAX8765 Only)
-2 +2 %
Charge-Current Offset
(MAX8765 Only)
-2 +2 mV
BATT/CSIP/CSIN Input Voltage
Range
0 19 V
V
DCIN
= 0 or V
ICTL
= 0 or SHDN = 0 1
CSIP/CSIN Input Current
Charging 650
µA
Cycle-by-Cycle Maximum Current
Limit
I
MAX
RS2 = 0.015Ω 6.0 7.5 A
ICTL Power-Down Mode
Threshold Voltage
(MAX1908/MAX8724 Only)
V
ICTL
rising
REFIN /
100
REFIN /
33
V
ICHG Transconductance
(MAX1908/MAX8724 Only)
V
CSIP
- V
CSIN
= 45mV 2.7 3.3
µA/mV
ICHG Transconductance
(MAX8765 Only)
V
CSIP
- V
CSIN
= 45mV
µA/mV
ICHG Transconductance Error
(MAX8765 Only)
%
ICHG Transconductance Offset
(MAX8765 Only)
µA
-0.6
-0.6
-0.6
70.5
-7.5
-7.5
G
ICHG
G
ICHG
2.785
-7.5
-6.5
+0.6
+0.6
+0.6
1.92
79.5
+7.5
+7.5
+50
+33
3.225
+7.5
+6.5
MAX1908/MAX8724/MAX8765
Low-Cost Multichemistry Battery Chargers
8 _______________________________________________________________________________________
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 = FLOAT, 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)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
CSIP
- V
CSIN
= 75mV
V
CSIP
- V
CSIN
= 45mV
ICHG Accuracy
V
CSIP
- V
CSIN
= 5mV -40
%
INPUT-CURRENT REGULATION
CSSP-to-CSSN Full-Scale
Current-Sense Voltage
mV
V
CLS
= V
REF
-5 +5
V
CLS
= V
REF
/ 2
Input Current-Limit Accuracy
V
CLS
= 1.1V (MAX8765 only) -10
%
Input Current-Limit Gain Error
(MAX8765 Only)
-2 +2 %
Input Current-Limit Offset
(MAX8765 Only)
-2 +2 mV
CSSP, CSSN Input Voltage
Range
8 28 V
V
DCIN
= 0 1
CSSP, CSSN Input Current
(MAX1908/MAX8724 Only)
V
CSSP
= V
CSSN
= V
DCIN
> 8V 600
µA
V
DCIN
= 0V 1
CSSP Input Current
(MAX8765 Only)
V
CSSP
= V
CSSN
= 28V
V
DCIN
= 28V 650
µA
V
DCIN
= 0V 1
CSSN Input Current
(MAX8765 Only)
V
CSSP
= V
CSSN
= 28V
V
DCIN
= 28V 1
µA
CLS Input Range
(MAX1908/MAX8724 Only)
1.6
V
CLS Input Range
(MAX8765 Only)
1.1
V
IINP Transconductance
(MAX1908/MAX8724 Only)
G
IINP
V
CSSP
- V
CSSN
= 75mV 2.7 3.3
µA/mV
IINP Transconductance
(MAX8765 Only)
G
IINP
V
CSSP
- V
CCSN
= 75mV
µA/mV
IINP Transconductance Error
(MAX8765 Only)
%
IINP Transconductance Offset
(MAX8765 Only)
-12
µA
V
CSSP
- V
CSSN
= 75mV
IINP Accuracy
V
CSSP
- V
CSSN
= 37.5mV
%
-7.5
-7.5
71.25
-7.5
2.785
-7.5
-7.5
-7.5
+7.5
+7.5
+40
78.75
+7.5
+10
REF
REF
3.225
+7.5
+12
+7.5
+7.5
MAX1908/MAX8724/MAX8765
Low-Cost Multichemistry Battery Chargers
_______________________________________________________________________________________ 9
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 = FLOAT, 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)
PARAMETER
CONDITIONS
UNITS
SUPPLY AND LDO REGULATOR
DCIN Input Voltage Range
8 28 V
DCIN Quiescent Current I
DCIN
8V < V
DCIN
< 28V 6 mA
V
BATT
= 19V, V
DCIN
= 0 1
BATT Input Current I
BATT
V
BATT
= 2V to 19V, V
DCIN
= 19.3V 500
µA
LDO Output Voltage 8V < V
DCIN
< 28V, no load
V
LDO Load Regulation 0 < I
LDO
< 10mA 100 mV
REFERENCE
REF Output Voltage 0 < I
REF
< 500µA
V
TRIP POINTS
V
DCIN
falling, referred to V
CSIN
(MAX1908/MAX8724 only)
50 150
BATT Power-Fail Threshold
V
CSSP
falling, referred to V
CSIN
(MAX8765 only)
50 150
mV
ACIN rising (MAX8765 only)
ACIN Threshold
ACIN rising (MAX1908/MAX8724 only)
V
SWITCHING REGULATOR
DHI Off-Time
V
BATT
= 16V, V
DCIN
= 19V,
V
CELLS
= V
REFIN
µs
DHI Minimum Off-Time
V
BATT
= 16V, V
DCIN
= 17V,
V
CELLS
= V
REFIN
µs
DHI Maximum On-Time 2.5 7.5 ms
DHI Maximum Duty Cycle 99 %
Battery Undervoltage Charge
Current
V
BATT
= 3V per cell (RS2 = 15mΩ),
MAX1908 only, V
BATT
rising
450 mA
CELLS = GND, MAX1908 only, V
BATT
rising
CELLS = float, MAX1908 only, V
BATT
rising
Battery Undervoltage Current
Threshold
V
DHI On-Resistance High V
BST
- VLX = 4.5V, I
DHI
= +100mA 7 Ω
DHI On-Resistance Low V
BST
- VLX = 4.5V, I
DHI
= -100mA 3.5 Ω
DLO On-Resistance High V
DLOV
= 4.5V, I
DLO
= +100mA 7 Ω
DLO On-Resistance Low V
DLOV
= 4.5V, I
DLO
= -100mA 3.5 Ω
SYMBOL
V
DCIN
MIN TYP MAX
5.25
4.065
2.028
2.007
0.35
0.24
CELLS = V
, MAX1908 only, V
REFIN
150
6.09
9.12
rising 12.18
BATT
5.55
4.120
2.068
2.089
0.45
0.33
6.30
9.45
12.60
Loading...