Typical operating characteristics (continued) – Rainbow Electronics MAX1543 User Manual
Page 7
MAX1542/MAX1543
TFT LCD DC-to-DC Converter with
Operational Amplifiers
_______________________________________________________________________________________
7
-30
100
100k
10k
1k
OPERATIONAL AMPLIFIER FREQUENCY
RESPONSE FOR VARIOUS C
LOAD
20
-10
-20
10
0
MAX1542 toc09
FREQUENCY (Hz)
MAGNITUDE (dB)
V
SUP
= 8V
A
V
= 1
R
L
= 10k
Ω
1000pF
15pF
56pF
100pF
100
0
1
100
1000
OPERATIONAL AMPLIFIER OVERSHOOT
vs. LOAD CAPACITANCE
20
MAX1542 toc10
LOAD CAPACITANCE (pF)
OVERSHOOT (%)
40
60
80
V
SUP
= 8V
R
L
= 10k
Ω
A
V
= 1
POS_ = 4V
±50mV
FALLING EDGE
RISING EDGE
Typical Operating Characteristics (continued)
(V
IN
= 3.3V, V
MAIN
= 8V, f
OSC
= 1.2MHz, T
A
= +25°C, unless otherwise noted.)
OPERATIONAL AMPLIFIER
OUTPUT LOW VOLTAGE vs. LOAD
MAX1542 toc12
I
OUT_
(mA)
V
OL
(mV)
8
6
4
2
40
80
120
160
0
0
10
V
SUP
= 8V
A
V
= 1
OPERATIONAL AMPLIFIER
OUTPUT HIGH VOLTAGE vs. LOAD
MAX1542 toc11
I
OUT_
(mA)
V
SUP
- V
OUT
(mV)
8
6
4
2
40
80
120
160
0
0
10
V
SUP
= 8V
A
V
= 1
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX1542 toc13
FREQUENCY (Hz)
PSRR (dB)
1k
100
10
1
20
40
60
80
100
120
0
0.1
10k
V
SUP
= 8V
OPERATIONAL AMPLIFIER
SETTLING TIME vs. STEP SIZE
MAX1542 toc14
STEP SIZE (V)
SETTLING TIME (ns)
1.4 1.6 1.8
1.0 1.2
0.4 0.6 0.8
0.2
100
50
200
150
300
250
400
450
350
500
0
0
2.0
V
SUP
= 8V
A
V
= +1
R
L
= 10k
Ω
C
L
= 10pF
V
CM
= 4V
RISING EDGE
FALLING EDGE
STEP-UP REGULATOR
LOAD-TRANSIENT RESPONSE
MAX1542 toc15
40
µs/div
I
MAIN
200mA/div
I
L
500mA/div
200mA
20mA
V
MAIN
AC-COUPLED
100mV/div
L = 4.7
µH
R
COMP
= 120k
Ω
C
COMP
= 470pF