MAX1779 Maxim, MAX1779 Datasheet - Page 8

• Manufacturer Part Number: MAX1779
• Description: Low-Power Triple-Output TFT LCD DC-DC Converter
• Manufacturer: Maxim

Low-Power Triple-Output TFT LCD DC-DC
Converter
(Circuit of Figure 5, V
8
_______________________________________________________________________________________
PIN
1
2
3
4
5
6
7
8
9
NAME
SHDN
INTG
GND
RDY
FBN
REF
FBP
FB
IN
IN
500mA
= +3.3V, T
5V
2V
3V
0
0
A. V
B. V
C. I
R
Active-Low Open-Drain Output. Indicates all outputs are ready. The on-resistance is 125Ω (typ).
Main Boost Regulator Feedback Input. Regulates to 1.25V nominal. Connect feedback resistive
divider to analog ground (GND).
Main Boost Integrator Output. If used, connect 2200pF to analog ground (GND). To disable
integrator, connect to REF.
Supply Input. +2.7V to +5.5V input range. Bypass with a 0.1µF capacitor between IN and GND, as
close to the pins as possible.
Analog Ground. Connect to power ground (PGND) underneath the IC.
Internal Reference Bypass Terminal. Connect a 0.22µF capacitor from this terminal to analog ground
(GND). External load capability to 50µA.
Positive Charge-Pump Regulator Feedback Input. Regulates to 1.25V nominal. Connect feedback
resistive divider to analog ground (GND).
Negative Charge-Pump Regulator Feedback Input. Regulates to 0V nominal.
Active-Low Logic-Level Shutdown Input. Connect SHDN to IN for normal operation.
MAIN
L
SHDN
MAIN
, 500mA/div
STARTUP WAVEFORM
A
= 50Ω
= +25°C, unless otherwise noted.)
= 0 to 2V, 2V/div
= 5V, 1V/div
(L = 33µH)
200µs/div
Typical Operating Characteristics (continued)
MAX1779-22
C
A
B
-10V
10V
5V
2V
0
0
0
FUNCTION
A. V
B. V
C. V
D. V
SHDN
MAIN
POWER-UP SEQUENCING
NEG
POS
= -8V, R
= +12V, R
= 5V, R
= 0 to 2V, 2V/div
4ms/div
NEG
MAIN
POS
= 8kΩ, 10V/div
= 12kΩ, 10V/div
= 50Ω, 2.5V/div
MAX1779-23
Pin Description
C
A
B
D