MAX1542 Datasheet, PDF (7/20 Pages) Maxim Integrated Products – TFT LCD DC-to-DC Converter with Operational Amplifiers

TFT LCD DC-to-DC Converter with
Operational Amplifiers
Typical Operating Characteristics (continued)
(V_IN = 3.3V, V_MAIN = 8V, f_OSC = 1.2MHz, T_A = +25°C, unless otherwise noted.)
OPERATIONAL AMPLIFIER FREQUENCY
RESPONSE FOR VARIOUS C_LOAD
20
10
1000pF
0
100pF
56pF
OPERATIONAL AMPLIFIER OVERSHOOT
vs. LOAD CAPACITANCE
100
V_SUP = 8V
R_L = 10kΩ
80 ^{AV = 1}
POS_ = 4V ±50mV
RISING EDGE
60
-10
15pF
40
FALLING EDGE
-20 _{VSUP = 8V}
A_V = 1
-30 ^{RL = 10kΩ}
100
1k
10k
100k
FREQUENCY (Hz)
OPERATIONAL AMPLIFIER
OUTPUT HIGH VOLTAGE vs. LOAD
160
V_SUP = 8V
A_V = 1
120
20
0
1
100
1000
LOAD CAPACITANCE (pF)
OPERATIONAL AMPLIFIER
OUTPUT LOW VOLTAGE vs. LOAD
160
V_SUP = 8V
A_V = 1
120
80
80
40
40
0
0
2
4
6
8
10
I_{OUT_} (mA)
0
0
2
4
6
8
10
I_{OUT_} (mA)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
120
100
80
60
40
20
V_SUP = 8V
0
0.1
1
10 100 1k 10k
FREQUENCY (Hz)
OPERATIONAL AMPLIFIER
SETTLING TIME vs. STEP SIZE
500
450
V_SUP = 8V
A_V = +1
400 RL = 10kΩ
350
C_L = 10pF
V_CM = 4V
300
250
RISING EDGE
FALLING EDGE
I_MAIN
200mA/div
I_L
500mA/div
200
150
V_MAIN
AC-COUPLED
100
100mV/div
50
0
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
STEP SIZE (V)
STEP-UP REGULATOR
LOAD-TRANSIENT RESPONSE
MAX1542 toc15
200mA
20mA
L = 4.7µH
R_COMP = 120kΩ
C_COMP = 470pF
40µs/div
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