Datasheet

4
LT1533
TYPICAL PERFORMANCE CHARACTERISTICS
UW
SWITCH CURRENT (A)
0
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0.6
1533 G03
0.2 0.4 0.8
125°C
25°C
1.0
SWITCH VOLTAGE (V)
85°C
DUTY CYCLE (%)
0
I
LIM
(mA)
0
50
100
150
200
250
300
10 20 30
125°C
25°C
40
1533 G02
50
Change in I
LIM
vs DC
Switch Voltage Drop
TEMPERATURE (°C)
–50
NEGATIVE FEEDBACK VOLTAGE (V)
NFB INPUT CURRENT (µA)
150
1533 G05
0
50
100
2.30
2.35
2.40
2.45
2.50
2.55
2.60
2.65
2.70
35
30
25
20
15
–25 25 75
125
V
NFB
I
NFB
Negative Feedback Voltage and
Input Current vs Temperature
Feedback Voltage and Input
Current vs Temperature
Switching Frequency vs
Feedback Pin Voltage
FEEDBACK PIN VOLTAGE (V)
0
SWITCHING FREQUENCY (% TYPICAL)
0.1
0.2
0.3 0.4
1533 G07
0.5
120
100
80
60
40
20
0
0.6
Error Amplifier Output Current
FEEDBACK PIN VOLTAGE FROM NOMINAL (mV)
400 –300 –200 –100
ERROR AMPLIFIER OUTPUT (µA)
400
1533 G08
0 100 300
200
500
400
300
200
100
0
100
200
300
400
500
125°C
–40°C
25°C
TEMPERATURE (°C)
V
C
PIN VOLTAGE (V)
1533 G09
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
–50 25 75
–25 0
50
100 125
V
C
PIN CLAMP
VOLTAGE
V
C
PIN
THRESHOLD
V
C
Pin Threshold and Clamp
Voltage vs Temperature
TEMPERATURE (°C)
–50
FEEDBACK VOLTAGE (V)
FEEDBACK INPUT CURRENT (µA)
1.30
1.29
1.28
1.27
1.26
1.25
1.24
1.23
1.22
1.21
1.20
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
50
75
1533 G04
–25 25
V
FB
I
FB
100
125
150
JUNCTION TEMPERATURE (°C)
INPUT VOLTAGE (V)
2.60
2.65
2.70
1533 G01
2.55
2.50
2.45
–50
0
50
75
–25 25
100
125
150
Minimum Input Voltage vs
Temperature
TEMPERATURE (°C)
TRANSCONDUCTANCE (mho)
1533 G06
2000
1900
1800
1700
1600
1500
1400
1300
1200
1100
1000
–50 25 75 150
–25 0
50
100 125
g
m
= I
VC
/V
FB
Error Amplifier Transconductance
vs Temperature