Datasheet

LTC4081
6
4081f
20
25
35
15
10
5
0
30
4081 G16
BATTERY VOLTAGE (V)
2.5
BUCK INPUT CURRENT (μA)
4.5
3.0
3.5
4.0
I
OUT
= 1mA
V
OUT
= 1.8V
L = 10μH
TEMPERATURE (°C)
0.80
NORMALIZED TIMER PERIOD
0.90
1.05
0.85
1.00
0.95
4081 G10
–50
30
–10
–30
50 70
10 90
BATTERY VOLTAGE (V)
2.5
2.26
2.27
2.28
4.0
4081 G11
2.25
2.24
3.0 3.5 4.5
2.23
2.22
FREQUENCY (MHz)
TEMPERATURE (°C)
–60
1.8
FREQUENCY (MHz)
1.9
2.0
2.1
2.2
–20 20
60
100
2.3
2.4
–40 0
40
80
4081 G12
V
BAT
= 2.7V
V
BAT
= 4.5V
V
BAT
= 3.8V
LOAD CURRENT (mA)
0.01
40
EFFICIENCY (%)
POWER LOSS (mW)
60
80
0.1 10 1001 1000
20
0
100
1
10
100
0.1
0.01
1000
4081 G13
V
BAT
= 3.8V
V
OUT
= 1.8V
L = 10μH
C = 4.7μF
EFFICIENCY
(BURST)
POWER LOSS
(BURST)
EFFICIENCY
(PWM)
POWER
LOSS
(PWM)
BATTERY VOLTAGE (V)
2.5
1.780
BUCK OUTPUT VOLTAGE (V)
1.785
1.790
1.795
1.800
1.805
1.810
3.0 3.5 4.0 4.5
4081 G14
PWM MODE
I
OUT
= 1mA
V
OUT
SET FOR 1.8V
Burst Mode
OPERATION
TEMPERATURE (˚C)
–50
BUCK OUTPUT VOLTAGE (V)
1.800
1.805
1.810
10 50
1.795
1.790
–30 –10
30 70 90
1.785
1.780
4081 G15
PWM MODE
Burst Mode
OPERATION
I
OUT
= 1mA
V
OUT
SET FOR 1.8V
No-Load Buck Input Current
(Burst Mode Operation)
vs Battery Voltage
Normalized Charge Termination
Time vs Temperature
Buck Oscillator Frequency
vs Battery Voltage
Buck Oscillator Frequency
vs Temperature
Buck Effi ciency vs Load Current
(V
OUT
= 1.8V)
Buck Output Voltage
vs Battery Voltage
Buck Output Voltage
vs Temperature
VOLTAGE (mV)
70
40
20
10
0
80
60
50
30
4081 G09
I
CHRG
= 5mA
TEMPERATURE (°
C)
–50
30
–10
–30
50 70
10 90
⎯
C
⎯
H
⎯
R
⎯
G Pin Output
Low Voltage vs Temperature
TYPICAL PERFORMANCE CHARACTERISTICS
(T
A
= 25°C, V
CC
= 5V, V
BAT
= 3.8V, unless otherwise
specifi ed)
Buck Effi ciency vs Load Current
(V
OUT
= 1.5V)
LOAD CURRENT (mA)
0.01
40
EFFICIENCY (%)
POWER LOSS (mW)
60
80
0.1 10 1001 1000
20
0
100
1
10
100
0.1
0.01
1000
4081 G13a
V
BAT
= 3.8V
V
OUT
= 1.5V
L = 10μH
C = 4.7μF
EFFICIENCY
(PWM)
POWER
LOSS
(PWM)
EFFICIENCY
(BURST)
POWER LOSS
(BURST)