Datasheet

LT1946A
3
sn1946a 1946afs
–50 –25 0 25 50 75 100 125
TEMPERATURE (°C)
FEEDBACK VOLTAGE (V)
1946A G01
1.28
1.27
1.26
1.25
1.24
1.23
1.22
1.21
1.20
FEEDBACK VOLTAGE (V)
0 0.2
0.4 0.6 0.8 1 1.2
OSCILLATOR FREQUENCY (kHz)
1946A G02
3000
2700
2400
2100
1800
1500
1200
900
600
300
0
T
A
= –30°C T
A
= 100°C
T
A
= 25°C
TEMPERATURE (°C)
–50 –25
0 25 50 75 100 125
CURRENT LIMIT (A)
1946A G03
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
SWITCH CURRENT (A)
0 0.2
0.4 0.6 0.8 1 1.2 1.4 1.6
V
CESAT
(V)
1946A G04
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
TEMPERATURE (°C)
QUIESCENT CURRENT (mA)
1946A G05
4.0
3.8
3.6
3.4
3.2
3.0
2.8
2.6
2.4
2.2
–50 –25 0 25 50 75 100 125
Feedback Pin Voltage Oscillator Frequency Current Limit
Switch Saturation Voltage Quiescent Current
Switching Waveforms for
Figure 1 Circuit
Start-Up Waveforms for
Figure 1 Circuit
Transient Response for
Figure 1 Circuit
100ns/DIV 1946A G06
R
LOAD
= 250Ω 1ms/DIV 1946A G08
50µs/DIV 1946A G07
V
OUT
2V/DIV
I
IN
200mA/DIV
0A
5V
0V
V
SHDN
V
OUT
100mV/DIV
AC COUPLED
250mA
150mA
I
LOAD
V
OUT
100mV/DIV
AC COUPLED
V
SW
10V/DIV
0V
I
LI
0.5A/DIV
TYPICAL PERFOR A CE CHARACTERISTICS
UW
I
LI
0.5A/DIV