MAX1542 Datasheet, PDF (9/20 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
LARGE-SIGNAL STEP RESPONSE
MAX1542 toc23
OPERATIONAL AMPLIFIER
SMALL-SIGNAL STEP RESPONSE
MAX1542 toc24
V_{OUT_}
1V/div
A_V = 1
1µs/div
CHI AMPL
4.86V
CHI + OVER
4.970%
POS_
50mV/div
AC-COUPLED
OUT_
50mV/div
AC-COUPLED
V_SUP = 8V, A_V = 1
200ns/div
CH2 + OVER
6.234%
CH2 - OVER
2.352%
PIN
MAX1542 MAX1543
1
1
2
2
3, 15, 20
—
—
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
11
11
12
12
13
13
Pin Description
NAME
FUNCTION
COM
SRC
N.C.
I.C.
PGND
AGND
POS1
NEG1
OUT1
OUT2
NEG2
POS2
SUP
LX
Internal High-Voltage MOSFET Switch Common Terminal. Do not allow the voltage on
COM to exceed V_SRC.
Switch Input. Source of the internal high-voltage P-channel MOSFET. Bypass SRC to
PGND with a minimum of 0.1µF close to the pins.
No Connection. Not internally connected.
Internal Connection. Make no connection to this pin.
Power Ground. PGND is the source of the main boost N-channel power MOSFET. Connect
PGND to the output capacitor ground terminals through a short, wide PC board trace.
Connect to analog ground (AGND) underneath the IC.
Analog Ground. Connect to power ground (PGND) underneath the IC.
Operational Amplifier 1 Noninverting Input
Operational Amplifier 1 Inverting Input
Operational Amplifier 1 Output
Operational Amplifier 2 Output
Operational Amplifier 2 Inverting Input
Operational Amplifier 2 Noninverting Input
Operational Amplifier Power Input. Positive supply rail for the OUT1 and OUT2 amplifiers.
Typically connected to V_MAIN. Bypass SUP to AGND with a 0.1µF capacitor.
Power MOSFET N-Channel Drain and Switching Node. Connect the inductor and catch
diode to LX and minimize the trace area for lowest EMI.
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