Datasheet

LT3971/LT3971-3.3/LT3971-5
6
3971fd
TYPICAL PERFORMANCE CHARACTERISTICS
EN Threshold
Minimum Input Voltage
T
A
= 25°C, unless otherwise noted.
TEMPERATURE (°C)
THRESHOLD VOLTAGE (V)
3971 G21
1.05
0.97
0.96
1.03
1.02
1.01
1.00
0.99
0.98
1.04
0.95
–55 15535 65 125955–25
RISING THRESHOLD
FALLING THRESHOLD
Minimum Input Voltage
LOAD CURRENT (mA)
0
INPUT VOLTAGE (V)
5.0
4.8
4.0
3.4
3.6
4.2
4.4
4.6
3.8
3.2
3.0
800400
3971 G19
1200600200 1000
TO START
TO RUN
V
OUT
= 3.3V
LOAD CURRENT (mA)
0
INPUT VOLTAGE (V)
6.4
6.2
5.4
5.6
6.0
5.8
5.2
5.0
800400
3971 G20
1200600200 1000
TO START
TO RUN
V
OUT
= 5V
Soft-StartLT3971-X Frequency Foldback
SS PIN VOLTAGE (V)
0
SWITCH CURRENT LIMIT (A)
2.5
2.0
0.5
1.0
1.5
0
1.250.75
3971 G18
210.50.25 1.751.5
V
OUT
(% OF REGULATION VOLTAGE)
0
SWITCHING FREQUENCY (kHz)
900
800
700
600
500
400
300
200
100
0
8040
3971 G30
1006020
Minimum Switch On-Time/
Switch Off-Time
TEMPERATURE (°C)
–55
SWITCH ON/OFF TIME (ns)
400
350
150
50
200
250
300
100
0
655
3971 G17
15535–25 95 125
MIN T
OFF
1A LOAD
MIN T
OFF
0.5A LOAD
MIN T
ON
Switch V
CESAT
Boost Pin Current Frequency Foldback
FB PIN VOLTAGE (V)
0
SWITCHING FREQUENCY (kHz)
900
800
400
200
500
600
700
300
100
0
0.80.4
3971 G16
1.20.60.2 1
SWITCH CURRENT (mA)
BOOST PIN CURRENT (mA)
3971 G15
30
20
15
10
5
25
0
0 1500500 750 1000 1250250
SWITCH CURRENT (mA)
V
CESAT
(mV)
3971 G14
600
400
300
200
100
500
0
0 1500500 750 1000 1250250