UC3842A, UC3843A, UC2842A, UC2843A
A VOL , OPEN LOOP VOLTAGE GAIN (dB)
100
80
Gain
60
40
Phase
20
0
120
150
100
1.0 k
10 k
100 k
1.0 M
180
10 M
V
CC
= 15 V
V
O
= 2.0 V to 4.0 V
R
L
= 100 K
T
A
= 25°C
Vth, CURRENT SENSE INPUT THRESHOLD (V
0
φ
EXCESS PHASE (DEGREES)
,
30
60
90
1.2
V
CC
= 15 V
1.0
0.8
0.6
T
A
= 125°C
0.4
0.2
0
T
A
= −55°C
T
A
= 25°C
− 20
10
0
f, FREQUENCY (Hz)
2.0
4.0
6.0
V
O
, ERROR AMP OUTPUT VOLTAGE (V)
8.0
Figure 8. Error Amp Open Loop Gain and
Phase versus Frequency
Figure 9. Current Sense Input Threshold
versus Error Amp Output Voltage
0
V
CC
= 15 V
ISC, REFERENCE SHORT CIRCUIT CURRENT (mA)
Δ
V ref , REFERENCE VOLTAGE CHANGE (mV)
110
V
CC
= 15 V
R
L
≤
0.1
W
90
−4.0
−8.0
−12
−16
−20
−24
T
A
= 125°C
T
A
= 25°C
70
T
A
= 55°C
0
20
40
60
80
100
120
50
−55
−25
0
25
50
75
100
125
I
ref
, REFERENCE SOURCE CURRENT (mA)
T
A
, AMBIENT TEMPERATURE (°C)
Figure 10. Reference Voltage Change
versus Source Current
Figure 11. Reference Short Circuit Current
versus Temperature
, OUTPUT VOLTAGE CHANGE (2.0 mV/DIV)
V
CC
= 15 V
I
O
= 1.0 mA to 20 mA
T
A
= 25°C
, OUTPUT VOLTAGE CHANGE (2.0 mV/DIV)
V
CC
= 12 V to 25 V
T
A
= 25°C
O
Δ
V
2.0 ms/DIV
Δ
V
O
2.0 ms/DIV
Figure 12. Reference Load Regulation
Figure 13. Reference Line Regulation
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