Datasheet

MAX1997/MAX1998
Quintuple/Triple-Output TFT LCD Power Supplies
with Fault Protection and VCOM Buffer
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS
(V
IN
= 3V, V
DDB
= 10V, SHDN = ONDC = FREQ = IN, C
REF
= 0.22µF, PGND = GND, T
A
= -40°C to +85°C, unless otherwise noted.)
(Note 3)
PARAMETER CONDITIONS
MIN TYP MAX
UNITS
IN Supply Range 2.7 5.5 V
V
IN
rising 2.5 2.9
IN Undervoltage Lockout Threshold
350mV typ
hysteresis
V
IN
falling 2.2 2.5
V
V
FB
= V
FBP
= V
FB1
= V
FB2
= 1.5V, V
FBN
= 0
(MAX1997 only)
1.25
IN Quiescent Current (Note 1)
V
FB
= V
FBP
= 1.5V, V
FBN
= 0 (MAX1998 only) 1
mA
-2µA < I
REF
< 50µA
1.223 1.270
REF Output Voltage
-2µA < I
REF
< 75µA
1.218 1.280
V
OVERCURRENT COMPARATOR
Input Offset Voltage V
OCN
= V
OCP
= 1.5V to 0.8V × V
IN
-5 +5 mV
Input Bias Current V
OCN
= V
OCP
= 0.8V × V
IN
-50 +50 nA
OCN, OCP Input Common-Mode Range
1.5
0.8 ×
V
IN
V
MAIN STEP-UP REGULATOR
Output Voltage Range V
IN
13 V
FREQ = IN 1 2
FREQ unconnected
0.563 0.937
Operating Frequency
FREQ = GND
0.25
0.50
MHz
Oscillator Maximum Duty Cycle 78 92 %
FB Regulation Voltage I
LX
= 200mA
1.215 1.260
V
FB Fault Trip Level V
FB
falling
0.96
1.04 V
FB Input Bias Current V
FB
= 1.5V
-100 +100
nA
LX On-Resistance 450 mΩ
LX Current Limit 1.6 2.8 A
POSITIVE LINEAR-REGULATOR CONTROLLERS (REG P, REG 1, AND REG 2)
I
DRVP
= 100µA
I
DRV1
= 1350µA (MAX1997 only)
FB_ Regulation Voltage
I
DRV2
= 335µA (MAX1997 only)
1.213 1.288
V
FB_ Fault Trip Level V
FB
_ falling
0.96
1.04 V
V
DRVP
= 10V, I
DRVP
= 0.05mA to 1mA
V
DRV1
= 10V, I
DRV1
= 0.5mA to 5mA
(MAX1997 only)
FB_ Effective Load Regulation Error
(Transconductance)
V
DRV2
= 10V, I
DRV2
= 0.1mA to 2mA
(MAX1997 only)
-2.5 %
DRVP Sink Current 1
DRV1 Sink Current (MAX1997 Only) 5
DRV2 Sink Current (MAX1997 Only)
V
FB
_ = 1.1V, V
DRV
_ = 10V
5
mA