Datasheet

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
- V
LX
= 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
SUPPLY AND LDO REGULATOR
DCIN Input Voltage Range V
DCIN
8 28 V
DCIN Quiescent Current I
DCIN
8.0V < V
DCIN
< 28V 6 mA
V
BATT
= 19V, V
DCIN
= 0V 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 5.25 5.55 V
LDO Load Regulation 0 < I
LDO
< 10mA 100 mV
REFERENCE
REF Output Voltage 0 < I
REF
< 500µA 4.065 4.120 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/MAX8765A only)
50 150
mV
ACIN rising (
MAX8765/MAX8765A
only) 2.028 2.068
ACIN Threshold
ACIN rising (MAX1908/MAX8724 only) 2.007 2.089
V
SWITCHING REGULATOR
DHI Off-Time
V
BATT
= 16V, V
DCIN
= 19V,
V
CELLS
= V
REFIN
0.35 0.45 µs
DHI Minimum Off-Time
V
BATT
= 16V, V
DCIN
= 17V,
V
CELLS
= V
REFIN
0.24 0.33 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
150 450 mA
CELLS = GND, MAX1908 only, V
BATT
rising 6.09 6.30
CELLS = open, MAX1908 only, V
BATT
rising 9.12 9.45
Battery Undervoltage Current
Threshold
CELLS = V
REFIN
, MAX1908 only, V
BATT
rising 12.18 12.60
V
DHI On-Resistance High V
BST
- V
LX
= 4.5V, I
DHI
= +100mA 7 Ω
DHI On-Resistance Low V
BST
- V
LX
= 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
Maxim Integrated
9
MAX1908/MAX8724/MAX8765/MAX8765A