Datasheet

MAX1997/MAX1998
Quintuple/Triple-Output TFT LCD Power Supplies
with Fault Protection and VCOM Buffer
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
IN, SHDN, FB, FBP, FBN, FB1, FB2, ONDC,
ONP, ONN, ON2, TGNDA, TGNDB to GND.............-0.3V to +6V
PGND to GND .....................................................................±0.3V
LX, V
DDB
to GND....................................................-0.3V to +14V
DRVP, DRV1, DRV2, DRVA to GND .......................-0.3V to +30V
REF, FREQ, GATE, OCN, OCP, CT,
PFLT to GND ..................................................-0.3V to V
IN
+ 0.3V
DRVN to GND ..........................................V
IN
- 28V to V
IN
+ 0.3V
FBPB, FBNB, OUTB to GND.......................-0.3V to V
DDB
+ 0.3V
OUTB Continuous Output Current ..................................±100mA
MAX1997 Continuous Power Dissipation (T
A
= +70°C)
32-Pin Thin QFN
(derate 21.2mW/°C above +70°C)............................1702mW
MAX1998 Continuous Power Dissipation (T
A
= +70°C)
20-Pin Thin QFN
(derate 20mW/°C above +70°C)...............................1600mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V
IN
= 3V, V
DDB
= 10V, SHDN = ONDC = FREQ = IN, C
REF
= 0.22µF, PGND = GND, T
A
= 0°C to +85°C.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER CONDITIONS
MIN TYP MAX
UNITS
IN Supply Range 2.7 5.5 V
V
IN
rising 2.5 2.7 2.9
IN Undervoltage Lockout Threshold
350mV (typ)
hysteresis
V
IN
falling 2.2
2.35
2.5
V
V
FB
= V
FBP
= V
FB1
= V
FB2
= 1.5V, V
FBN
= 0
(MAX1997 only)
0.54
1.25
IN Quiescent Current (Note 1)
V
FB
= V
FBP
= 1.5V, V
FBN
= 0 (MAX1998 only)
0.476
1
mA
IN Shutdown Current V
SHDN
= 0, V
IN
= 5.5V 0.1 1 µA
-2µA < I
REF
< 50µA
1.231 1.250 1.269
REF Output Voltage
-2µA < I
REF
< 75µA
1.225 1.250 1.275
V
Thermal Shutdown
160
°C
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
FAULT TIMER
PFLT = GND (MAX1997 only)
21.8
PFLT unconnected (MAX1997 only)
43.6
Fault Timer Period
PFLT = IN, or MAX1998
87.2
ms
GATE Output Sink Current During Slew V
GATE
= 1.5V during turn-on transition 5 10 15 µA
GATE Output Pulldown Resistance V
GATE
< 0.5V 200 Ω
GATE Output Pullup Resistance 200 Ω
MAIN STEP-UP REGULATOR
Output Voltage Range V
IN
13 V
FREQ = IN 1.5
FREQ unconnected
0.637 0.75 0.863
Operating Frequency
FREQ = GND
0.375
MHz