MAX8570–MAX8575
High-Efficiency LCD Boost
with True Shutdown
4 _______________________________________________________________________________________
EFFICIENCY vs. BATTERY VOLTAGE
(FIGURE 4)
MAX8570/71/73/74/75 toc07
BATTERY VOLTAGE (V)
EFFICIENCY (%)
108642
50
60
70
80
90
100
40
012
L1 = MURATA LQH32CN220K23
5mA LOAD
1mA LOAD
V
CC
= 3.6V
EFFICIENCY vs. LOAD CURRENT
WITH 22μH INDUCTOR
MAX8570/71/73/74/75 toc08
LOAD CURRENT (mA)
EFFICIENCY (%)
101
50
60
70
80
90
100
40
0.1 100
MAX8574, TOKO A914BYW-220M
MAX8571, MURATA LQH32CN220K23
MAX8570, MURATA LQH32CN220K23
EFFICIENCY vs. LOAD CURRENT
WITH 47μH INDUCTOR
MAX8570/71/73/74/75 toc09
LOAD CURRENT (mA)
EFFICIENCY (%)
101
50
60
70
80
90
100
40
0.1 100
MAX8570, L1 = MURATA LQH32CN470K23
MAX8571, L1 = TOKO A914BYW-470M
PEAK INDUCTOR CURRENT LIMIT
vs. SUPPLY VOLTAGE
MAX8570/71/73/74/75 toc10
SUPPLY VOLTAGE (V)
CURRENT LIMIT (mA)
5.14.74.33.93.53.1
100
200
300
400
500
600
700
0
2.7 5.5
MAX8574
MAX8571
MAX8570
SUPPLY CURRENT vs. LOAD CURRENT
MAX8570/71/73/74/75 toc11
LOAD CURRENT (mA)
SUPPLY CURRENT (mA)
105
20
40
60
80
100
120
0
015
L1 = MURATA LQH32CN220K23
NO-LOAD CURRENT vs. SUPPLY VOLTAGE
MAX8570/71/73/74/75 toc12
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (μA)
541 2 3
10
20
30
40
50
60
70
80
0
06
R1 = 3.9M
Ω
R2 = 287k
Ω
R1 = 7.87M
Ω
R2 = 576k
Ω
MAX8573,
FIGURE 3
L1 = MURATA
LQH32CN220K23
NO SWITCHING
LINE TRANSIENT 3V TO 5.5V (MAX8571)
MAX8570/71/73/74/75 toc13
100μs/div
V
CC
V
OUT
200mV/div
(AC-COUPLED)
2V/div
0
3.6kΩ LOAD, R1 = 3.9MΩ, R2 = 287kΩ
LINE TRANSIENT 3V TO 5.5V
(FIGURE 3, MAX8573)
MAX8570/71/73/74/75 toc14
100μs/div
V
CC
V
OUT
200mV/div
(AC-COUPLED)
2V/div
0
3kΩ LOAD
Typical Operating Characteristics (continued)
(MAX8571, V
CC
= 3.6V, V
OUT
= 18V, Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)