1.8V to 28V Input, PWM Step-Up
Controllers in µMAX
Typical Operating Characteristics (continued)
(Circuits of Figures 2, 3, 4, and 5; T
A
= +25°C; unless otherwise noted.)
EXITING SHUTDOWN
MAX668 toc14
MAX668/MAX669
ENTERING SHUTDOWN
MAX668 toc15
0V
OUTPUT
VOLTAGE
5V/div
INDUCTOR
CURRENT
2A/div
SHUTDOWN
VOLTAGE
5V/div
500µs/div
MAX668, V
IN
= 5V, V
OUT
= 12V, LOAD = 1.0A, R
OSC
= 100kΩ,
LOW VOLTAGE, NON-BOOTSTRAPPED
0A
SHUTDOWN
VOLTAGE
5V/div
0V
0V
OUTPUT
VOLTAGE
5V/div
200µs/div
MAX668, V
IN
= 5V, V
OUT
= 12V, LOAD = 1.0A,
LOW VOLTAGE, NON-BOOTSTRAPPED
0V
HEAVY-LOAD SWITCHING WAVEFORM
MAX668 toc16
LIGHT-LOAD SWITCHING WAVEFORM
V
OUT
100mV/div
AC-COUPLED
MAX668 toc17
V
OUT
200mV/div
AC-COUPLED
Q1, DRAIN
5V/div
0V
Q1, DRAIN
5V/div
0V
I
L
1A/div
1µs/div
MAX668, V
IN
= 5V, V
OUT
= 12V, I
LOAD
= 1.0A,
LOW VOLTAGE, NON-BOOTSTRAPPED
0A
I
L
1A/div
1µs/div
MAX668, V
IN
= 5V, V
OUT
= 12V, I
LOAD
= 0.1A,
LOW VOLTAGE, NON-BOOTSTRAPPED
0A
LOAD-TRANSIENT RESPONSE
MAX668 toc18
LINE-TRANSIENT RESPONSE
MAX668 toc19
OUTPUT
VOLTAGE
AC-COUPLED
100mV/div
OUTPUT
VOLTAGE
100mV/div
AC-COUPLED
LOAD
CURRENT
1A/div
1ms/div
MAX668, V
IN
= 5V, V
OUT
= 12V, I
LOAD
= 0.1A TO 1.0A,
LOW VOLTAGE, NON-BOOTSTRAPPED
INPUT
VOLTAGE
5V/div
20ms/div
MAX668, V
IN
= 5V TO 8V, V
OUT
= 12V, LOAD = 1.0A,
HIGH VOLTAGE, NON-BOOTSTRAPPED
0V
_______________________________________________________________________________________
7
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
