Rainbow Electronics MAX8728 - Manual (Page 9)

MAX8728
Low-Cost, Multiple-Output
Power Supply for LCD Monitors/TVs
_______________________________________________________________________________________ 9
Typical Operating Characteristics (continued)
(Circuit of Figure 1. V
IN
= V
INL
= V
SUPP
= 12V, AV
DD
= 13.5V, V
GON
= 28V, V
GOFF
= -6V, V
OUT1
= 3.3V, FSEL = GND, T
A
= +25°C,
unless otherwise noted.)
STEP-UP REGULATOR
SOFT-START (HEAVY LOAD)
MAX8728toc07
0V
0V
0V
EN, 2V/div
INDUCTOR CURRENT,
500mA/div
1ms/div
AV DD , 5V/div
GATE, 5V/div
STEP-UP REGULATOR LOAD TRANSIENT
RESPONSE (100mA TO 600mA)
MAX8728toc08
0V
0V
LOAD CONTROL,
5V/div
INDUCTOR CURRENT,
500mA/div
AV DD , AC,
200mV/div
10 μs/div
STEP-UP REGULATOR PULSED-LOAD
TRANSIENT RESPONSE (100mA TO 1A)
MAX8728toc09
0V
0V
LOAD CONTROL,
5V/div
INDUCTOR CURRENT,
500mA/div
AV DD , AC,
100mV/div
4 μs/div
TIMER-DELAY
OVERCURRENT PROTECTION
MAX8728toc10
0V
VGON, 20V/div,
10k
Ω LOAD
INDUCTOR CURRENT,
1A/div
10ms/div
V GOFF , 5V/div, AVDD, 10k Ω LOAD
OUT1, 2V/div, 2.5A OVERLOAD
AV DD , 5V/div, 150 Ω LOAD
SWITCHING FREQUENCY
vs. INPUT VOLTAGE
INPUT VOLTAGE (V)
SWITCHING FREQUENCY (MHz)
MAX8728 toc11
7 8 9 10 11 12 13
1.500
1.505
1.510
1.515
1.520
FSEL = GND
NORMALIZED VL OUTPUT VOLTAGE
vs. VL CURRENT
VL CURRENT (mA)
VL VOLTAGE (V)
MAX8728 toc12
0 10 20 30 40 50 60 70
4.80
4.85
4.90
4.95
5.00
5.05
EN = GND
EN = VL