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