Datasheet

LTC3225/LTC3225-1
4
3225fb
Oscillator Frequency vs
Supply Voltage
Charge Pump Open-Loop Output
Resistance vs Temperature
(2V
IN
– V
COUT
)/I
OUT
TYPICAL PERFORMANCE CHARACTERISTICS
(T
A
= 25°C, C
FLY
= 1μF, C
IN
= 2.2μF, C
TOP
= C
BOT
, unless otherwise specifi ed)
I
OUT
(mA)
20
4
5
7
80 120
3225 G04
3
40 60
100 140 160
2
6
EXTRA I
IN
(mA)
V
IN
= 3.6V
CHARGE PUMP IS ON
V
OUT
= 4.5V
V
OUT
= 5V
V
OUT
= 3.7V
V
OUT
= 4.2V
V
IN
(V)
2.5
0
I
IN
(µA)
5
10
15
20
30
3
3.5 4 4.5
3225 G05
5 5.5
25
T
A
= 85°C
T
A
= 25°C
T
A
= –40°C
V
IN
20mV/DIV
I
VIN
200mA/DIV
200ns/DIV
3225 G08
R
PROG
= 12k
0mA
Charging Profi le with Unequal
Initial Output Capacitor Voltage
(Initial V
TOP
= 1.3V, V
BOT
= 1V)
V
IN
(V)
2.5
0.88
FREQUENCY (MHz)
0.89
0.91
0.92
3
3.5
4 4.5
3225 G07
5
0.93
0.94
0.90
5.5
T
A
= 25°C
T
A
= 85°C
T
A
= –40°C
TEMPERATURE (°C)
–40
R
OL
()
7.5
8.0
8.5
35
85
3225 G06
7.0
6.5
6.0
–15 10 60
9.0
9.5
10.0
V
OUT
= 3.7V
(LTC3225-1)
V
OUT
= 4.5V
(LTC3225)
V
IN
= 3.6V
SHDN
5V/DIV
V
COUT
2V/DIV
V
TOP
-V
BOT
500mV/DIV
I
VIN
300mA/DIV
2 SEC/DIV
3225 G09
LTC3225
V
SEL
= V
IN
R
PROG
= 12k
C
TOP
= C
BOT
= 1.1F
C
TOP
INITIAL VOLTAGE = 1.3V
C
BOT
INITIAL VOLTAGE = 1V
Extra Input Current vs Output
Current (I
VIN
– 2 • I
OUT
)
No-Load Input Current vs
Supply Voltage
Input Ripple and Input Current
I
OUT
vs R
PROG
Effi ciency vs V
IN
I
OUT
vs V
OUT
(R
PROG
= 12k)
R
PROG
(k)
10
I
OUT
(mA)
60
80
100
40
60
3225 G01
40
20
0
20 30 50
120
140
160
V
IN
= 3.6V
V
OUT
= 4.5V (LTC3225)
V
OUT
(V)
0
0
I
OUT
(mA)
20
60
80
100
2
4
5
180
3225 G02
40
13
0.5
2.5
4.5
1.5 3.5
120
140
160
V
IN
= 2.8V
V
IN
= 3.6V
V
IN
= 5.5V
C
TOP
= C
BOT
V
IN
(V)
2.5
0
EFFICIENCY (%)
10
30
40
50
4.5
100
90
3525 G03
20
3.5
3
5
4 5.5
60
70
80
V
SEL
= V
IN
V
SEL
= 0
I
LOAD
= 100mA
C
TOP
= C
BOT
LTC3225
LTC3225-1