lt1976 Linear Technology Corporation, lt1976 Datasheet - Page 7

• Manufacturer Part Number: lt1976
• Description: High Voltage 1.5a, 200khz Step-down Switching Regulator With 100?a Quiescent Current
• Manufacturer: Linear Technology Corporation

TYPICAL PERFOR A CE CHARACTERISTICS
100mA/
50mV/
V
700
600
400
300
200
4.0
3.5
3.0
2.5
2.0
1.5
1.0
DIV
I
DIV
500
100
0.5
OUT
SW
0A
0
0
–50
2
Dropout Operation
LT1976 Burst Mode Operation
LT1976B V
vs Temperature
V
V
I
Q
V
BOOST DIODE = DIODES INC. B1100
IN
OUT
OUT
= 100μA
= 12V
–30
= 3.3V
= 3.3V
2.5
–10
INPUT VOLTAGE (V)
TIME (10μs/DIV)
TEMPERATURE (˚C)
C
10
LOAD CURRENT = 1.25A
LOAD CURRENT = 250mA
Switching Threshold
3
30
3.5
50
70
W
4
90 110
1976 G23
1976 G15
1976 G26
U
4.5
100mA/DIV
50mV/DIV
COUPLED
V
500
450
400
350
300
250
200
150
100
OUT
I
AC
SW
50
0A
0
6
5
4
3
1
0
2
–50
2
LT1976B No Load Operation
(Pulse-Skipping Mode)
Minimum On Time
Dropout Operation
V
V
I
Q
V
BOOST DIODE = DIODES INC. B1100
IN
OUT
= 1.6mA
OUT
= 12V
–30
LOAD CURRENT = 250mA
2.5
LOAD CURRENT = 0.5A
= 3.3V
LOAD CURRENT = 1A
= 5V
–10
3
TEMPERATURE (°C)
INPUT VOLTAGE (V)
TIME (10μs/DIV)
10
3.5
LOAD CURRENT = 1.25A
30
4
50
4.5
70
5
90 110
5.5
1976 G21
1976 G27
1976 G24
6
500mA/DIV
100mA/DIV
100mV/DIV
50mV/DIV
I
V
OUT
V
OUT
I
OUT
SW
0A
1A
0A
50
45
40
35
30
25
20
15
10
5
0
LT1976/LT1976B
LT1976 Burst Mode Operation
V
V
I
LT1976 No Load 1A
Step Response
V
V
C
0
Boost Current vs Load Current
Q
IN
OUT
IN
OUT
OUT
= 100μA
= 12V
= 12V
= 3.3V
200
= 3.3V
= 47μF
400
LOAD CURRENT (mA)
TIME (5ms/DIV)
TIME (1ms/DIV)
600
800 1000
1200 1400
1976 G22
1976 G14
1976 G17
1976bfg
7