Datasheet

MAX1997/MAX1998
Quintuple/Triple-Output TFT LCD Power Supplies
with Fault Protection and VCOM Buffer
_______________________________________________________________________________________ 9
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
IN
= 3.3V, V
MAIN
= 9V, V
G_ON
= 20V, V
G_OFF
= -7V, V
LOGIC
= 2.5V, V
GAMMA
= 8.6V, T
A
= +25°C,
unless otherwise noted.)
REG P (GATE-ON VOLTAGE)
LOAD REGULATION
MAX1997 toc14
LOAD CURRENT (mA)
OUTPUT-VOLTAGE VARIATION (%)
1
-0.20
-0.15
-0.10
-0.05
0
-0.25
0.1 10
REG N (GATE-OFF VOLTAGE)
LOAD REGULATION
MAX1997 toc15
LOAD CURRENT (mA)
OUTPUT-VOLTAGE VARIATION (%)
1
-0.32
-0.24
-0.16
-0.08
0
-0.40
0.1 10
REG 1 (LOGIC SUPPLY)
LOAD REGULATION
MAX1997 toc16
LOAD CURRENT (mA)
OUTPUT-VOLTAGE VARIATION (%)
-0.8
-0.6
-0.4
-0.2
0
-1.0
1 1000
10010
REG 2 (GAMMA REFERENCE)
LOAD REGULATION
MAX1997 toc17
LOAD CURRENT (mA)
OUTPUT-VOLTAGE VARIATION (%)
1
-0.16
-0.12
-0.08
-0.04
0
-0.20
0.1 10
REG 1 (LOGIC SUPPLY)
LOAD TRANSIENT RESPONSE
MAX1997 toc18
40µs/div
B
A
2.49V
300mA
2.5V
0
100mA
200mA
A: LOAD CURRENT, 0 TO 250mA, 100mA/div
B: V
LOGIC
= 2.5V, 10mV/div, AC-COUPLED
REG 2 (GAMMA REFERENCE)
V
MAIN
TRANSIENT REJECTION
MAX1997 toc19
4µs/div
B
A
8.8V
20V
8.58V
8.60V
8.62V
0
A: V
LX
, 20V/div
B: V
GAMMA
= 8.6V, 20mV/div, AC-COUPLED
C: V
MAIN
= 9V, 200mV/div, AC-COUPLED
D: I
MAIN
= 0 TO 1A, 1A/div
0
1A
9.0V
D
C