Manual

MAX1684/MAX1685
Low-Noise, 14V Input, 1A, PWM
Step-Down Converters
_______________________________________________________________________________________ 5
100
0
0.1 1 10 100 1000 10,000
MAX1684
EFFICIENCY vs. LOAD CURRENT
(V
IN
= 3.3V, V
OUT
= 1.8V, 2.5V)
20
10
MAX1684/85 toc01
LOAD CURRENT (mA)
EFFICIENCY (%)
40
30
60
80
90
70
50
A: V
OUT
= 2.5V LP MODE
B: V
OUT
= 1.8V LP MODE
C: V
OUT
= 2.5V NORM MODE
D: V
OUT
= 1.8V NORM MODE
E: V
OUT
= 2.5V PWM MODE
F: V
OUT
= 1.8V PWM MODE
A
D
E
B
F
C
100
0
0.1 1 10 100 1000 10,000
MAX1684
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 3.3V)
20
10
MAX1684/85 toc02
LOAD CURRENT (mA)
EFFICIENCY (%)
40
30
60
80
90
70
50
A: V
IN
= 4V LP MODE
B: V
IN
= 12V LP MODE
C: V
IN
= 4V NORMAL MODE
D: V
IN
= 12V NORMAL MODE
D
C
A
B
1 10010 1000 10,000
MAX1684
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 3.3V, PWM MODE)
MAX1684/85 toc03
LOAD CURRENT (mA)
EFFICIENCY (%)
100
0
20
10
50
40
30
70
60
90
80
A: V
IN
= 4V
B: V
IN
= 5V
C: V
IN
= 9V
D: V
IN
= 12V
C
B
A
D
100
20
0.1 1 10 100 1000 10,000
MAX1684
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 5V)
40
30
MAX1684/85 toc04
LOAD CURRENT (mA)
EFFICIENCY (%)
50
70
90
80
60
A: V
IN
= 6V LP MODE
B: V
IN
= 9V LP MODE
C: V
IN
= 12V LP MODE
D: V
IN
= 6V NORMAL MODE
E: V
IN
= 9V NORMAL MODE
F: V
IN
= 12V NORMAL MODE
E
B
F
E
D
A
C
100
0
0.1 1 10 100 1000 10,000
MAX1685
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 3.3V)
20
10
MAX1684/85 toc07
LOAD CURRENT (mA)
EFFICIENCY (%)
40
30
60
80
90
70
50
A: V
IN
= 4V LP MODE
B: V
IN
= 12V LP MODE
C: V
IN
= 4V NORMAL MODE
D: V
IN
= 12V NORMAL MODE
D
C
B
A
1 10010 1000 10,000
MAX1684
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 5V, PWM MODE)
MAX1684/85 toc05
LOAD CURRENT (mA)
EFFICIENCY (%)
100
0
20
10
50
40
30
70
60
90
80
A: V
IN
= 6V
B: V
IN
= 9V
C: V
IN
=12V
C
B
A
1 10010 1000 10,000
MAX1685
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 3.3V, PWM MODE)
MAX1684/85 toc06
LOAD CURRENT (mA)
EFFICIENCY (%)
100
0
20
10
50
40
30
70
60
90
80
V
IN
= 5V
V
IN
= 9V
V
IN
= 12V
V
IN
= 4V
1 10010 1000 10,000
MAX1685
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 5V PWM MODE)
MAX1684/85 toc08
LOAD CURRENT (mA)
EFFICIENCY (%)
100
0
20
10
50
40
30
70
60
90
80
V
IN
= 6V
V
IN
= 9V
V
IN
=12V
100
0
0.1 1 10 100 1000 10,000
MAX1685
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 5V)
20
10
MAX1684/85 toc09
LOAD CURRENT (mA)
EFFICIENCY (%)
40
30
60
80
90
70
50
A: V
IN
= 6V LP MODE
B: V
IN
= 9V LP MODE
C: V
IN
= 12V LP MODE
D: V
IN
= 6V NORMAL MODE
E: V
IN
= 9V NORMAL MODE
F: V
IN
=12V NORMAL MODE
A
F
E
D
C
B
Typical Operating Characteristics
(Circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)