Datasheet

LT1976/LT1976B
6
1976bfg
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Switch Peak Current Limit
Soft-Start Current Threshold
vs FB Voltage
Oscillator Frequency
vs FB Voltage
TEMPERATURE (°C)
–50
1.5
PEAK SWITCH CURRENT (A)
2.0
2.5
3.0
3.5
–25 –0 25 50
1976 G10
75 100 150125
FB VOLTAGE (V)
0
0
CURRENT (μA)
10
20
30
0.2
0.4
0.6 0.8
1976 G11
1.0
40
50
5
15
25
35
45
1.2
SOFT-START
DEFEATED
T
J
= 25°C
FB VOLTAGE (V)
0
0
FREQUENCY (kHz)
50
100
150
0.2
0.4
0.6 0.8
1976 G12
1.0
200
250
1.2
T
J
= 25°C
Switch On Voltage (V
CESAT
)
LOAD CURRENT (A)
0
VOLTAGE (mV)
50
150
200
250
500
350
0.7
0.9
1976 G13
100
400
450
300
0.5
1.1
1.3
1.5
T
J
= 125°C
T
J
= 25°C
T
J
= –50°C
INPUT VOLTAGE (V)
0
0
SUPPLY CURRENT (μA)
50
100
10
20
30 40
1976 F05
50
150
25
75
125
60
V
OUT
= 3.3V
T
A
= 25°C
LT1976 Supply Current
vs Input Voltage
LOAD CURRENT (mA)
0
INPUT VOLTAGE (V)
5.5
6.0
6.5
1600
1976 G19
5.0
4.5
3.0
400
800
1200
200
600
1000
1400
4.0
3.5
7.5
7.0
5V START
3.3V START
5V RUNNING
3.3V RUNNING
Minimum Input Voltage
LT1976 Burst Mode Threshold
vs Input Voltage
INPUT VOLTAGE (V)
5
LOAD CURRENT (mA)
120
160
200
21
1975 G20
80
40
100
140
180
60
20
0
97
1311
17 19 23
15
25
V
OUT
= 3.3V
L = 33μH
C
OUT
= 100μF
PGFB Threshold
VOLTAGE (V)
1976 G08
1.16
1.08
1.04
1.00
1.20
1.12
1.14
1.06
1.02
1.18
1.10
TEMPERATURE (°C)
–50 0
50
75
–25
25
100
150125
PG Sink Current
CURRENT (μA)
1976 G08
200
100
50
0
250
150
TEMPERATURE (°C)
–50 0
50
75
–25
25
100
150125