MAX1790 Maxim, MAX1790 Datasheet - Page 4

• Manufacturer Part Number: MAX1790
• Description: Low-Noise Step-Up DC-DC Converter
• Manufacturer: Maxim

Low-Noise Step-Up DC-DC Converter
(Circuit of Figure 1, V
4
_______________________________________________________________________________________
80
75
95
90
85
70
65
50
60
55
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
2.5
1
EFFICIENCY vs. OUTPUT CURRENT
NO-LOAD SUPPLY CURRENT
3.0
f
L = 5.4µH
OSC
vs. INPUT VOLTAGE
OUTPUT CURRENT (mA)
f
= 640kHz
OSC
3.5
INPUT VOLTAGE (V)
10
= 1.2MHz
IN
f
L = 2.7µH
OSC
= 3.3V, f
4.0
= 1.2MHz
f
OSC
100
4.5
= 640kHz
OSC
V
V
V
OUT
IN
OUT
5.0
= 3.3V
= 12V
= 5V
= 640kHz, T
1000
5.5
12.10
12.05
12.00
11.95
11.90
11.85
11.80
11.75
11.70
11.65
11.60
A
95
90
85
80
75
70
65
50
60
55
= +25°C, unless otherwise noted.)
1
OUTPUT VOLTAGE vs. OUTPUT CURRENT
0
EFFICIENCY vs. OUTPUT CURRENT
20
f
L = 10µH
OSC
T
A
40 60 80
= 640kHz
= +25°C
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
10
100 120 140
Typical Operating Characteristics
T
f
L = 5.4µH
A
OSC
= +85°C
100
= 1.2MHz
f
OSC
V
V
T
A
IN
OUT
160
= -40°C
= 640kHz
= 3.3V
= 12V
180
1000
200
200mA
10mA
95
90
85
80
75
70
65
50
60
55
CH1
CH2
CH3
1
CH1 = LOAD CURRENT, 100mA/div
CH2 = OUTPUT VOLTAGE, AC-COUPLED, 200mV/div
CH3 = INDUCTOR CURRENT, 1A/div
V
V
IN
OUT
EFFICIENCY vs. OUTPUT CURRENT
= 3V
f
L = 10µH
OSC
= 12V, f
LOAD-TRANSIENT RESPONSE
R
C
C
COMP
COMP
COMP2
= 640kHz
OUTPUT CURRENT (mA)
OSC
= 120kΩ
= 1200pF
10
= 56pF
= 640kHz, C
100µs/div
f
L = 5.4µH
OSC
OUT
100
= 1.2MHz
= 33µF + 0.1µF
V
V
IN
OUT
= 5V
= 12V
1000