Datasheet

LT3689/LT3689-5
5
3689fe
For more information www.linear.com/LT3689
TYPICAL PERFORMANCE CHARACTERISTICS
No-Load Supply Current vs V
IN
No-Load Supply Current Maximum Load Current, 5V
OUT
Maximum Output Current, 3.3V
OUT
Switch Current Limit
vs Duty Cycle
Switch Current Limit
vs Temperature
Switch Voltage Drop
Maximum V
IN
for Full FrequencyMaximum V
IN
for Full Frequency
INPUT VOLTAGE (V)
0
SUPPLY CURRENT (µA)
80
100
120
35
60
40
10 20
5
15 25 30 40
20
0
140
3689 G04
T
A
= 25°C
TEMPERATURE (°C)
–50
0
200
400
600
–25
0
25 50 10075 125
100
300
500
700
150
3689 G05
CATCH DIODE: DIODES INC. B140HB
V
IN
= 12V
V
OUT
= 3.3V
INCREASED SUPPLY
CURRENT DUE TO
CATCH DIODE LEAKAGE
AT HIGH TEMPERATURE
0
0.4
0.8
1.2
0.2
0.6
1.0
1.4
V
IN
(V)
6
LOAD CURRENT (A)
12 18 3024 36
3689 G06
MINIMUM
TYPICAL
T
A
= 25°C
L = 12µH
f = 1MHz
0
0.4
0.2
0.60.3
0.1
0.5 0.7
LOAD CURRENT (A)
0
V
IN
(V)
10
20
30
40
5
15
25
35
3689 G07
V
O
= 5V
L = 6.8µH
f = 2MHz
SYNC = 5V
T
A
= 25°C
T
A
= 85°C
0
0.4
0.2
0.60.3
0.1
0.5 0.7
LOAD CURRENT (A)
0
V
IN
(V)
10
20
30
5
15
25
35
3689 G08
V
O
= 3.3V
L = 4.7µH
f = 2MHz
SYNC = 3.3V
T
A
= 25°C
T
A
= 85°C
V
IN
(V)
4
0
LOAD CURRENT (A)
0.4
0.8
1.2
8
12
16 20 2824 32
0.2
0.6
1.0
36
3689 G09
T
A
= 25°C
L = 12µH
f = 700kHz
MINIMUM
TYPICAL
DUTY CYCLE (%)
0
0
CURRENT LIMIT (A)
0.4
0.8
1.2
1.6
2.0
20
40 60 80
100
3689 G10
T
A
= 25°C
SYNC = LOW
MINIMUM
TYPICAL
TEMPERATURE (°C)
0
0.5
1.0
1.5
2.0
3689 G11
SYNC = HIGH
SYNC = LOW
–50 –25
0
25 50 10075 125 150
SWITCH CURRENT (mA)
0
VOLTAGE DROP (mV)
400
500
300
200
400 800
200
600 1000
100
0
600
3689 G12
T
A
= 125°C
T
A
= 25°C
T
A
= –50°C