Typical operating characteristics – Rainbow Electronics MAX1842 User Manual
Page 5
Typical Operating Characteristics
(Circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)
MAX1742/MAX1842
1A/2.7A, 1MHz, Step-Down Regulators with
Synchronous Rectification and Internal Switches
_______________________________________________________________________________________
5
100
95
90
85
80
70
65
60
55
50
75
0.001
0.01
1
MAX1742
EFFICIENCY vs. OUTPUT CURRENT
(V
IN
= 5.0V, L = 6.0
µH)
MAX1742 toc01
OUTPUT CURRENT (A)
EFFICIENCY (%)
0.1
V
OUT
= 1.8V, R
TOFF
= 75k
Ω,
f = 833kHz
V
OUT
= 1.5V, R
TOFF
= 100k
Ω, f = 692kHz
V
OUT
= 2.5V, R
TOFF
= 47k
Ω, f = 926kHz
100
95
90
85
80
70
65
60
55
50
75
0.001
0.01
1
MAX1742
EFFICIENCY vs. OUTPUT CURRENT
(V
IN
= 3.3V, L = 3.9
µH)
MAX1742 toc02
OUTPUT CURRENT (A)
EFFICIENCY (%)
0.1
V
OUT
= 2.5V, R
TOFF
= 36k
Ω
, f = 456kHz
V
OUT
= 1.8V, R
TOFF
= 43k
Ω
, f = 869kHz
V
OUT
= 1.5V, R
TOFF
= 56k
Ω
, f = 833kHz
100
95
90
85
80
70
65
60
55
50
75
0.001
0.01
1
MAX1742
EFFICIENCY vs.OUTPUT CURRENT
(f
PWM
= 270kHz)
MAX1742 toc03
OUTPUT CURRENT (A)
EFFICIENCY (%)
0.1
V
IN
= 5V, V
OUT
= 1.8V,
L = 15
µ
H, R
TOFF
= 240k
Ω
V
IN
= 3.3V, V
OUT
= 1.8V,
L = 10
µ
H, R
TOFF
= 160k
Ω
0.5
0.4
0.3
0.2
0.1
-0.1
-0.2
-0.3
-0.4
-0.5
0
0.001
0.01
1
MAX1742
NORMALIZED OUTPUT ERROR
vs. OUTPUT CURRENT
MAX1742 toc04
OUTPUT CURRENT (A)
NORMALIZED OUTPUT ERROR (%)
0.1
V
IN
= 5V, V
OUT
= 1.5V, L = 6
µH
V
IN
= 3.3V, V
OUT
= 1.5V
0
300
100
200
600
900
700
1100
1000
400
500
800
0
0.2
0.4
0.6
0.8
1.0
MAX1742
SWITCHING FREQUENCY
vs. OUTPUT CURRENT
MAX1742 toc05
OUTPUT CURRENT (A)
FREQUENCY (kHz)
V
IN
= 5V, V
OUT
= 2.5V, L = 6
µ
H
V
IN
= 5V, V
OUT
= 1.5V, L = 6
µ
H
V
IN
= 3.3V, V
OUT
= 1.5V, L = 3.9
µ
H