UC3842A, UC3843A, UC2842A, UC2843A
80
50
100
V
= 15 V
CC
50
20
T = 25°C
A
20
8.0
5.0
10
5.0
V
= 15 V
2.0
0.8
CC
2.0
1.0
T = 25°C
A
10 k
20 k
50 k
100 k
200 k
500 k
1.0 M
10 k
20 k
50 k
100 k
200 k
500 k
1.0 M
f , OSCILLATOR FREQUENCY (Hz)
OSC
f , OSCILLATOR FREQUENCY (Hz)
OSC
Figure 2. Timing Resistor versus
Oscillator Frequency
Figure 3. Output Deadtime versus
Oscillator Frequency
9.0
8.5
8.0
7.5
7.0
100
90
80
70
60
V
= 15 V
C = 3.3 nF
CC
V
V
= 15 V
= 2.0 V
CC
T
OSC
T = 25°C
A
I
= 7.2 mA
dischg
50
40
I
= 9.5 mA
dischg
800 1.0 k
2.0 k
3.0 k 4.0 k
6.0 k 8.0 k
−55
−25
0
25
50
75
100
125
T , AMBIENT TEMPERATURE (°C)
A
R , TIMING RESISTOR (ꢃ)
T
Figure 4. Oscillator Discharge Current
versus Temperature
Figure 5. Maximum Output Duty Cycle
versus Timing Resistor
V
A = −1.0
T = 25°C
A
= 15 V
V
A = −1.0
T = 25°C
A
= 15 V
CC
CC
3.0 V
2.5 V
2.0 V
V
V
2.55 V
2.5 V
2.45 V
0.5 ꢀ s/DIV
0.1 ꢀ s/DIV
Figure 6. Error Amp Small Signal
Transient Response
Figure 7. Error Amp Large Signal
Transient Response
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