UC3844B, UC3845B, UC2844B, UC2845B
0
30
1.2
1.0
0.8
0.6
0.4
0.2
0
100
80
V
CC
= 15 V
V
V
= 15 V
= 2.0 V to 4.0 V
CC
O
R = 100 k
L
T = 25°C
A
Gain
60
60
T = 25°C
A
90
40
T = 125°C
A
Phase
120
150
180
20
T = −ꢁ55°C
A
0
−ꢁ20
0
2.0
4.0
6.0
8.0
10
100
1.0 k
10 k
100 k
1.0 M
10 M
V , ERROR AMP OUTPUT VOLTAGE (V )
O O
f, FREQUENCY (Hz)
Figure 6. Error Amp Open Loop Gain and
Phase versus Frequency
Figure 7. Current Sense Input Threshold
versus Error Amp Output Voltage
0
110
V
= 15 V
CC
V
CC
= 15 V
R ≤ 0.1 W
L
−ꢁ4.0
−ꢁ8.0
−ꢁ12
−ꢁ16
−ꢁ20
−ꢁ24
90
70
50
T = −ꢂ55°C
A
T = 125°C
A
T = 25°C
A
0
20
40
60
80
100
120
−ꢁ55
−ꢁ25
0
25
50
75
100
125
I , REFERENCE SOURCE CURRENT (mA)
ref
T , AMBIENT TEMPERATURE (°C)
A
Figure 8. Reference Voltage Change
versus Source Current
Figure 9. Reference Short Circuit Current
versus Temperature
V
= 15 V
= 1.0 mA to 20 mA
CC
V
= 12 V to 25 V
CC
I
O
T = 25°C
A
T = 25°C
A
2.0 ms/DIV
2.0 ms/DIV
Figure 10. Reference Load Regulation
Figure 11. Reference Line Regulation
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