Typical operating characteristics (continued) – Rainbow Electronics MAX1678 User Manual
Page 5
MAX1678
1-Cell to 2-Cell, Low-Noise,
High-Efficiency, Step-Up DC-DC Converter
_______________________________________________________________________________________
5
90
50
COILCRAFT
EFFICIENCY WITH DIFFERENT INDUCTORS
55
85
80
DS1608C-473
DT1608C-223
CD43-470
47
µ
H
47
µ
H
47
µ
H
47
µ
H
22
µ
H
47
µ
H
22
µ
H
22
µ
H
CD43-220
LQH4N470K
LQH3C470K
NLC453232T-470K
NLC453232T-220K
MAX1678-10
EFFICIENCY (%)
75
70
65
60
V
BATT
= 1.2V
V
OUT
= 3.3V
I
LOAD
= 20mA
SUMIDA
MURATA
TDK
1000
10
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
NO-LOAD BATTERY CURRENT
vs. INPUT VOLTAGE
MAX1678-11
INPUT VOLTAGE (V)
NO-LOAD BATTERY CURRENT (
µ
A)
100
V
OUT
= 5.0V
R1 = 3M
Ω
, R2 = 1M
Ω
V
OUT
= 3.0V
FB = GND
L1 = 47
µ
H
SUMIDA CD43-470
V
OUT
= 2.4V
R1 = 1M
Ω
, R2 = 1M
Ω
45
0
-40
100
BATT AND OUT QUIESCENT CURRENT
vs. TEMPERATURE
10
5
40
35
30
MAX1678-12
TEMPERATURE (°C)
QUIESCENT CURRENT (
µ
A)
0
-20
80
60
40
20
25
20
15
V
BATT
= 1.3V
V
OUT
= 3.6V
FB = GND
I
OUT
I
BATT
12
0
0
6
SHUTDOWN BATTERY CURRENT
vs. INPUT VOLTAGE
2
10
8
MAX1678-13
INPUT VOLTAGE (V)
SHUTDOWN BATTERY CURRENT (
µ
A)
2
1
5
4
3
6
4
3.3V FIXED MODE
L1 = 47
µ
H
SUMIDA CD43-470
140
0
0
5.0
MAXIMUM LOAD CURRENT
vs. INPUT VOLTAGE
(L1 = 22
µ
H)
20
120
100
MAX1678-16
INPUT VOLTAGE (V)
MAXIMUM LOAD CURRENT (mA)
1.5
1.0
0.5
4.5
3.5 4.0
3.0
2.5
2.0
80
60
40
L1 = 22
µ
H
SUMIDA CD43-220
V
OUT
= 3.3V
V
OUT
= 5.0V
V
OUT
= 2.4V
9.0
7.6
-40
100
ON-TIME CONSTANT (K)
vs. TEMPERATURE
7.8
8.8
8.6
MAX1678-14
TEMPERATURE (°C)
ON-TIME CONSTANT (V-
µ
s)
0
-20
80
60
40
20
8.4
8.2
8.0
V
BATT
= 1.3V
1.3
0.6
0
35
MINIMUM START-UP INPUT VOLTAGE
vs. LOAD CURRENT
0.7
1.2
1.1
MAX1678-15
LOAD CURRENT (mA)
START-UP INPUT VOLTAGE (V)
10
5
30
25
20
15
1.0
0.9
0.8
L1 = 47
µ
H
SUMIDA CD43-470
3.3V FIXED MODE
WITH EXTERNAL
SCHOTTKY DIODE
(FIGURE 3)
WITHOUT
DIODE
140
0
0
5.0
MAXIMUM LOAD CURRENT
vs. INPUT VOLTAGE
(L1 = SUMIDA 47
µ
H)
20
120
100
MAX1678-17
INPUT VOLTAGE (V)
MAXIMUM LOAD CURRENT (mA)
1.5
1.0
0.5
4.5
3.5 4.0
3.0
2.5
2.0
80
60
40
L1 = 47
µ
H
SUMIDA CD43-470
V
OUT
= 5.0V
V
OUT
= 3.3V
V
OUT
= 2.4V
140
0
0
5.0
MAXIMUM LOAD CURRENT
vs. INPUT VOLTAGE
(L1 = TDK 47
µ
H)
20
120
100
MAX1678-18
INPUT VOLTAGE (V)
MAXIMUM LOAD CURRENT (mA)
1.5
1.0
0.5
4.5
3.5 4.0
3.0
2.5
2.0
80
60
40
L1 = 47
µ
H
TDK NLC453232T-470K
V
OUT
= 5.0V
V
OUT
= 3.3V
V
OUT
= 2.4V
Typical Operating Characteristics (continued)
(Circuit of Figure 7 (Fixed Mode, 3.3V) or Figure 8 (Adjustable Mode), T
A
= +25°C, unless otherwise noted.)