Datasheet

LT3980
6
3980fa
For more information www.linear.com/LT3980
FB PIN ERROR VOLTAGE (mV)
–200
–50
V
C
PIN CURRENT (µA)
–20
0
20
0 200
50
3980 G20
–40
–100 100
40
10
–10
30
–30
Error Amp Output Current
TEMPERATURE (°C)
V
C
VOLTAGE (V)
1.50
2.00
2.50
3980 G23
1.00
0.50
0
CURRENT LIMIT CLAMP
SWITCHING THRESHOLD
–50 25–25 0 50 75 100 150125
3980 G25
I
L
0.2A/DIV
V
SW
5V/DIV
V
OUT
10mV/DIV
5µs/DIV
V
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 10mA
TEMPERATURE (°C)
THRESHOLD VOLTAGE (%)
85
90
95
3980 G24
80
75
–50 25–25 0 50 75 100 150125
3980 G26
I
L
0.2A/DIV
V
SW
5V/DIV
V
OUT
10mV/DIV
V
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 110mA
1µs/DIV
3980 G27
I
L
0.5A/DIV
V
SW
5V/DIV
V
OUT
10mV/DIV
V
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 1A
1µs/DIV
Minimum Input Voltage,
V
OUT
= 3.3V
Minimum Input Voltage,
V
OUT
= 5V V
C
Voltages Power Good Threshold
Switching Waveforms:
Transition from Burst Mode
Operation to Full Frequency
Switching Waveforms: Full
Frequency Continuous Operation
Switching Waveforms:
Burst Mode Operation
T
A
= 25°C, unless otherwise noted.
Typical perFormance characTerisTics
BOOST DIODE CURRENT (A)
0
BOOST DIODE V
F
(V)
0.8
1.0
1.2
2.0
3980 G19
0.6
0.4
0
0.5 1.0 1.5
0.2
1.4
Boost Diode
1 10 100 1000 2000
f = 400kHz
I
LOAD
(mA)
INPUT VOLTAGE (V)
4
5
3980 G21
3
2
6
TO START
TO RUN
I
LOAD
(mA)
INPUT VOLTAGE (V)
6
7
3980 G22
5
4
8
1 10 100 1000 2000
TO START
TO RUN
f = 400kHz
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