LTC1558-3.3/LTC1558-5
TYPICAL PERFORMANCE CHARACTERISTICS
Output Power vs Battery Voltage
150
125
OUTPUT POWER (mW)
V
CC
= 5V (LTC1558-5)
V
BAK
= 6V
SWITCHING FREQUENCY (kHz)
100
75
50
25
0
1.0
1.1
1.2
1.3
NiCd TERMINAL VOLTAGE (V)
1.4
1558 G01
BACKUP TIME (HOURS)
Boost Converter Switching
Duty Cycle
100
TRICKLE CHARGE FACTOR (mA/mA)
10.5
CURRENT RATIO (mA/mA)
80
DUTY CYCLE (%)
60
40
20
V
BATT
= 1.2V
V
CC
= 3.3V (LTC1558-3.3)
I
PK
= 330mA
2
6
4
8
OUTPUT VOLTAGE, V
BAK
(V)
10
1558 G04
0
Fast Recharge Time (Assume
Fully Exhausted NiCd Battery)
60
50
RESET VOLTAGE (V)
40
30
20
10
0
6
TIME (HOURS)
4
3
2
1
0
4.7V
4.55V
0
1
2
3
4
SUPPLY VOLTAGE (V)
5
6
1558 G08
RESET VOLTAGE (V)
64
128
256
BATTERY CAPACITY (mAHr)
4
U W
512
1558 G07
Backup Time vs Battery Capacity
3.0
2.5
2.0
1.5
1.0
0.5
0
0
125
250
375
NiCd CELL CAPACITY (mAHr)
500
1558 G02
Boost Converter Switching
Frequency
125
V
BATT
= 1.2V
V
CC
= 3.3V (LTC1558-3.3)
I
PK
= 330mA
V
BATT
= 1.2V
V
BAK
= 6V
P
OUT
= 100mW
100
75
50
25
0
2
6
4
8
OUTPUT VOLTAGE, V
BAK
(V)
10
1558 G03
Trickle Charge Multiplier Factor
1.005
V
BATT
= 1.2V
10.0
9.5
9.0
8.5
8.0
7.5
0.05
Normalized Fast Recharge
Current vs Temperature
1.000
0.995
0.990
0.985
0.980
0.975
0.970
0.965
0.960
0.955
0.950
0.1
1
NiCd BATTERY TRICKLE CURRENT (mA)
2
0
25
50
TEMPERATURE (°C)
75
1558 G06
1558 G05
RESET Output Voltage
vs Supply Voltage
3.5
V
CC
= 5V (LTC1558-5)
5
3.0
2.5
2.0
1.5
1.0
0.5
0
RESET Output Voltage
vs Supply Voltage
V
CC
= 3.3V (LTC1558-3.3)
3.10V
3V
0
2
3
1
SUPPLY VOLTAGE (V)
4
1558 G09
LINER [ LINEAR TECHNOLOGY ]
