Manual

MAX1790
Low-Noise Step-Up DC-DC Converter
4 _______________________________________________________________________________________
Typical Operating Characteristics
(Circuit of Figure 1, V
IN
= 3.3V, f
OSC
= 640kHz, T
A
= +25°C, unless otherwise noted.)
MAX1790-01
50
1 100010010
EFFICIENCY vs. OUTPUT CURRENT
65
55
85
75
95
70
60
90
80
OUTPUT CURRENT (mA)
EFFICIENCY (%)
f
OSC
= 1.2MHz
L
= 2.7
µ
H
V
IN
= 3.3V
V
OUT
= 5V
f
OSC
= 640kHz
L
= 5.4
µ
H
50
1 100010010
EFFICIENCY vs. OUTPUT CURRENT
65
55
85
75
95
70
60
90
80
MAX1790-02
OUTPUT CURRENT (mA)
EFFICIENCY (%)
f
OSC
= 1.2MHz
L
= 5.4
µ
H
V
IN
= 3.3V
V
OUT
= 12V
f
OSC
= 640kHz
L
= 10
µ
H
OUTPUT CURRENT (mA)
50
1 100010010
EFFICIENCY vs. OUTPUT CURRENT
65
55
85
75
95
70
60
90
80
MAX1790-03
EFFICIENCY (%)
f
OSC
= 1.2MHz
L
= 5.4
µ
H
V
IN
= 5V
V
OUT
= 12V
f
OSC
= 640kHz
L
= 10
µ
H
0
0.2
0.1
0.4
0.3
0.6
0.5
0.7
2.5 3.5 4.03.0 4.5 5.0 5.5
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX1790-04
INPUT VOLTAGE (V)
NO-LOAD SUPPLY CURRENT (mA)
V
OUT
= 12V
f
OSC
= 1.2MHz
f
OSC
= 640kHz
11.60
11.70
11.65
11.80
11.75
11.90
11.85
11.95
12.05
12.00
12.10
0 40608020 100 120 140 180160 200
OUTPUT VOLTAGE vs. OUTPUT CURRENT
MAX1790-05
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
f
OSC
= 640kHz
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
200mA
10mA
CH1
CH2
CH3
CH1 = LOAD CURRENT, 100mA/div
CH2 = OUTPUT VOLTAGE, AC-COUPLED, 200mV/div
CH3 = INDUCTOR CURRENT, 1A/div
V
IN
= 3V
V
OUT
= 12V, f
OSC
= 640kHz, C
OUT
= 33
µ
F + 0.1
µ
F
100
µ
s/div
LOAD-TRANSIENT RESPONSE
MAX1790-06
R
COMP
= 120k
Ω
C
COMP
= 1200pF
C
COMP2
= 56pF