lt3688fe Linear Technology Corporation, lt3688fe Datasheet - Page 5

• Manufacturer Part Number: lt3688fe
• Description: Lt3688 - Dual 800ma Step-down Switching Regulator With Power-on Reset And Watchdog Timer
• Manufacturer: Linear Technology Corporation

TYPICAL PERFORMANCE CHARACTERISTICS
160
140
120
100
350
300
250
200
150
100
1.5
0.5
80
60
40
20
50
0
2
1
0
0
0
0
0
No-Load Supply Current (Input)
Maximum Load Current (3.3V)
Switch Voltage Drop
f
SW
= 1MHz
200
10
10
SWITCH CURRENT (mA)
INPUT VOLTAGE (V)
400
L = 15μH
V
IN
20
20
(V)
L = 10μH
600
V
30
30
OUT2
V
800
OUT1
= 3.3V
3688 G04
3688 G07
3688 G10
= 5V
1000
40
40
3000
2500
2000
1500
1000
500
1.8
1.6
1.4
1.2
0.8
0.6
0.4
0.2
25
20
15
10
0
–50 –25
1
0
5
0
0
0
No-Load Supply Current
(Temperature)
Switch Current Limit
vs Duty Cycle
BST Pin Current
CATCH DIODE: B140HB
V
V
V
IN
OUT1
OUT2
= 12V
= 5V
= 3.3V
200
20
0
SWITCH CURRENT (mA)
INCREASED SUPPLY
CURRENT DUE TO CATCH
DIODE LEAKAGE AT HIGH
TEMPERATURE
TEMPERATURE (°C)
DUTY CYCLE (%)
25
400
40
TYPICAL
MIN
50
600
60
75
100 125 150
800
80
3688 G05
T
3688 G08
3688 G11
A
1000
= 25°C unless otherwise noted.
100
0.810
0.805
0.800
0.795
0.790
2.0
1.5
1.0
0.5
1.5
0.5
0
2
1
0
–50 –25
–50 –20
0
Feedback Voltage
Maximum Load Current (5V)
Switch Current Limit
vs Temperature
DC = 15%
f
SW
= 1MHz
10
0
0
TEMPERATURE (°C)
TEMPERATURE (°C)
INPUT VOLTAGE (V)
25
25
L = 15μH
50
50
20
L = 10μH
LT3688
75
75
100 125 150
100 125
30
3688 G09
3688 G06
3688 G12
5
3688f
150
40