Manual

MAX8621Y/MAX8621Z
Dual Step-Down DC-DC Power-Management ICs
for Portable Devices
_______________________________________________________________________________________ 7
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.)
OUT1 OUPUT VOLTAGE
vs. INPUT VOLTAGE
MAX8621 toc05
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
5.04.54.03.53.0
2.525
2.550
2.575
2.600
2.625
2.650
2.500
2.5 5.5
LOAD = 0
LOAD = 300mA
FALLING
RISING
OUT2 OUTPUT VOLTAGE ACCURACY
vs. LOAD CURRENT
MAX8621 toc06
LOAD CURRENT (mA)
OUTPUT VOLTAGE ACCURACY (%)
25020050 100 150
-1.5
-1.0
-0.5
0
0.5
1.0
1.5
2.0
-2.0
0 300
OUT4 DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX8621 toc07
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
10050
20
40
60
80
100
120
140
160
0
0 150
OUT1 POWER-SUPPLY
RIPPLE REJECTION vs. FREQUENCY
MAX8621 toc08
FREQUENCY (kHz)
POWER-SUPPLY RIPPLE REJECTION (dB)
100101
10
20
30
40
50
60
70
80
0
0.1 1000
EFFICICENCY vs. LOAD CURRENT
(V
BUCK2
= 1.8V)
MAX8621 toc09
LOAD CURRENT (mA)
EFFICIENCY (%)
100101
50
60
70
80
90
100
40
0.1 1000
2.2µH
4.7µH
1µH
BUCK1, OUT1, OUT2:
ON WITH NO LOAD
EFFICICENCY vs. LOAD CURRENT
(V
BUCK1
= 1.375V)
MAX8621 toc10
LOAD CURRENT (mA)
EFFICIENCY (%)
100101
50
60
70
80
90
100
40
0.1 1000
2.2µH
4.7µH
1µH
BUCK2, OUT1, OUT2:
ON WITH NO LOAD