100% Duty Cycle, Low-Noise,
Step-Down, PWM DC-DC Converter
_____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 2, TA = +25°C, unless otherwise noted.)
LOAD-TRANSIENT RESPONSE
LINE-TRANSIENT RESPONSE
A
B
C
40µs/div
VIN = 5V, VOUT = 3.3V,
LOAD = 0mA TO 500mA, PWM MODE
A: LX, 5V/div
B: VOUT, 50mV/div, AC COUPLED
C: LOAD CURRENT, 500mA/div
A
B
200µs/div
VIN = 5V TO 11V, VOUT = 3.3V,
LOAD = 500mA, PWM MODE
A: VIN, 5V/div
B: VOUT, 20mV/div, AC COUPLED
RECOVERY FROM 100% DUTY CYCLE
(DROP OUT)
A
B
C
200µs/div
VIN = 3.3V TO 11V, VOUT = 3.3V,
LOAD = 500mA, PWM MODE
A: VIN, 5V/div
B: VOUT, 50mV/div, AC COUPLED
C: LX, 10V/div
SHUTDOWN AND STARTUP RESPONSE
A
B
C
D
500µs/div
VIN = 5V, VOUT = 3.3V,
LOAD = 100mA, PWM MODE
A: SHDN, 5V/div
B: VOUT, 2V/div, AC COUPLED
C: LX, 5V/div
D: INDUCTOR CURRENT, 500mA/div
6 _______________________________________________________________________________________