Datasheet
MAX1997/MAX1998
Quintuple/Triple-Output TFT LCD Power Supplies
with Fault Protection and VCOM Buffer
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(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
FBN Effective Load Regulation Error
(Transconductance)
V
DRVN
= -10V, I
DRVN
= 50µA to 1mA 18 25 mV
FBN Line (IN) Regulation Error I
DRVN
= 100µA, 2.7V < V
IN
< 5.5V 1 mV
Bandwidth (Note 2)
1000
kHz
DRVN Source Current V
FBN
= 200mV, V
DRVN
= -10V 2 4.2 mA
DRVN Leakage Current V
FBN
= -0.1V, V
DRVN
= -20V 0.1 10 µA
Soft-Start Period 4096/f
OSC
s
Soft-Start Step Size V
REF
/32 V
VCOM BUFFER (MAX1997 only)
V
DDB
Supply Range 4.5 13 V
V
DDB
Supply Current V
FBPB
= V
FBNB
= 5V, V
DDB
= 9V
367
900 µA
V
DDB
Shutdown Current V
DDB
= 13V, SHDN = ONDC = GND 3.5 13 µA
Input Offset Voltage V
FBPB
= 2.5V, no load -5 +5 mV
Input Bias Current V
FBPB
= V
FBNB
= 1.2V to V
DDB
- 1.2V 1 µA
Input Offset Current V
FBPB
= V
FBNB
= 1.2V to V
DDB
- 1.2V
-100
+100
nA
Input Common-Mode Range V
DDB
= 4.5V to 13V 1.2
V
DDB
-
1.2
V
Power-Supply Rejection Ratio V
DDB
= 4.5V to 13V, V
FBPB
= 2.25V 70 dB
Common-Mode Rejection Ratio V
FBPB
= V
FBNB
= 1.2V to V
DDB
- 1.2V 70 dB
Gain-Bandwidth Product Small signal
1/6πC
L
Hz
Load-Transient Settling Time
R
L
= 25Ω, C
L
= 10nF, V
DRIVE
= 9V, settle to within
10mV (Note 4)
5 µs
Small signal (±1mV overdrive) 0.3
Transconductance
Large signal (±30mV overdrive) 7.2
µS
Output Current Drive ±100mV overdrive, V
OUTB
= 3V or 7V
±150 ±300
mA
LOGIC SIGNALS (SHDN, ONDC)
Input Low Voltage 100mV typ hysteresis 0.4 V
Input High Voltage 1.6 V
Input Current
0.01
1 µA
CONTROL INPUTS AND OUTPUTS
ONN, ONP, ON2 Comparator Offset V
O N _
- V
CT
, V
CT
= 1.25V ±50mV -50 +50 mV
DRVA Sink Current V
DRVA
= 10V, V
CT
= 1.25V, V
ON2
= 2V 5 11 mA
DRVA Off-Leakage V
DRVA
= 28V, V
CT
= 1.25V, V
ON2
= 1V 0.1 10 µA
CT Source Current V
CT
= 1V 2.5 5 7.5 µA
CT Discharge Resistance V
CT
= 1V 15 100 Ω
FREQ, PFLT Input Low Voltage 1V
FREQ, PFLT Input Middle Voltage
V
IN
/2
FREQ, PFLT Input High Voltage
V
IN
- 1
V
FREQ, PFLT Input Current FREQ, PFLT = GND or IN -50 +50 µA