Datasheet

MAX1870A
Step-Up/Step-Down
Li+ Battery Charger
_______________________________________________________________________________________ 7
PARAMETER CONDITIONS
MIN TYP MAX
UNITS
SUPPLY AND LINEAR REGULATOR
DCIN Input Voltage Range 8 28 V
DCIN falling 4
DCIN Undervoltage Lockout
DCIN rising
7.85
V
DCIN Quiescent Current 8.0V < V
DCIN
< 28V 6 mA
BATT Input Voltage Range 0 19 V
BATT Input Bias Current
V
BATT
= 2V to 19V 500
µA
LDO Output Voltage No load 5.3 5.5 V
LDO Undervoltage Lockout V
DCIN
= 8V, LDO rising
4.00 5.25
V
REFERENCE
REF Output Voltage I
REF
= 0µA
4.060 4.132
V
REF Load Regulation 0 < I
REF
< 500µA 10 mV
REF Undervoltage-Lockout Trip
Point
V
REF
falling 3.9 V
REFIN Input Range 2.5 3.6 V
REFIN UVLO Rising 2.2 V
REFIN Input Bias Current V
DCIN
= 18V 100 µA
SWITCHING REGULATOR
C ycl e- b y- C ycl e S tep - U p M axi m um
C ur r ent- Li m i t S ense V ol tag e
V
DCIN
= 12V, V
BATT
= 16.8V 130 170 mV
C ycl e- b y- C ycl e S tep - D ow n
M axi m um C ur r ent- Li m i t S ense
V ol tag e
V
DCIN
= 19V, V
BATT
= 16.8V 130 170 mV
Step-Down On-Time V
DCIN
= 18V, V
BATT
= 16.8V
2.2 2.6 µs
Minimum Step-Down Off-Time V
DCIN
= 18V, V
BATT
= 16.8V
0.15 0.50
µs
Step-Up Off-Time V
DCIN
= 12V, V
BATT
= 16.8V 1.6 2.0 µs
Minimum Step-Up On-Time V
DCIN
= 12V, V
BATT
= 16.8V
0.15 0.40
µs
MOSFET DRIVERS
VHP - VHN Output Voltage 8V < V
VHP
< 28V, no load 4.5 5.5 V
VHN Load Regulation 0 < I
VHN
< 10mA 150 mV
DHI On-Resistance High I
SOURCE
= 10mA 5 Ω
DHI On-Resistance Low I
SINK
= 10mA 3 Ω
VHP Input Bias Current
V
DCIN
= 18V 2
mA
BLKP Input Bias Current
V
ICTL
= V
REFIN
= 3.3V 400
µA
DLOV Supply Current DBST low 10 µA
DBST On-Resistance High I
SOURCE
= 10mA 5 Ω
DBST On-Resistance Low I
SINK
= 10mA 3 Ω
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 2, V
DCIN
= V
CSSP
= V
CSSN
= V
CSSS
= V
VHP
= 18V, V
BATT
= V
CSIP
= V
CSIN
= V
BLKP
= 12V, V
REFIN
= 3.0V, V
ICTL
=
0.75 x V
REFIN
, VCTL = LDO, CELLS = FLOAT, GND = PGND = 0, V
DLOV
= 5.4V, T
A
= -40°C to +85°C.) (Note 1)