Manual

MAX8621Y/MAX8621Z
Dual Step-Down DC-DC Power-Management ICs
for Portable Devices
8 _______________________________________________________________________________________
SWITCHING FREQUENCY
vs. LOAD CURRENT
MAX8621 toc11
LOAD CURRENT (mA)
FREQUENCY (MHz)
100 200 300 400
1
10
0.1
0 500
1µH
2.2µH
4.7µH
BUCK1 OUTPUT VOLTAGE
vs. LOAD CURRENT (VOLTAGE POSITIONING)
MAX8621 toc15
LOAD CURRENT (mA)
OUTPUT VOLTAGE (V)
400300200100
1.32
1.34
1.36
1.38
1.40
1.42
1.44
1.30
0 500
BUCK1 LIGHT-LOAD WAVEFORMS
MAX8621 toc12
200ns/div
10mV/div
AC-COUPLED
V
BUCK1
I
LX1
V
LX1
200mA/div
0
5V/div
0
LOAD = 50mA
BUCK1 LOAD-TRANSIENT RESPONSE
MAX8621 toc14
5µs/div
50mV/div
AC-COUPLED
V
BUCK1
I
LX1
I
BUCK1
500mA/div
0
500mA/div
0
400mA LOAD
BUCK1 HEAVY-LOAD WAVEFORMS
MAX8621 toc13
200ns/div
10mV/div
AC-COUPLED
V
BUCK1
I
LX1
V
LX1
200mA/div
0
5V/div
0
LOAD = 300mA
Typical Operating Characteristics (continued)
(Circuit of Figure 3, V
IN1
= V
IN2
= V
IN3
= 3.6V, PWRON = IN, V
BUCK1
= 1.375V, V
BUCK2
= 1.8V, V
OUT1
= 2.6V, V
OUT2
= 2.6V, V
OUT3
= 1.8V, V
OUT4
= 3.0V, SEL1 = SEL2 = open, LX1 = LX2 = Murata LQH32CN2R2M53, T
A
= +25°C, unless otherwise noted.)