UC3842B, UC3843B, UC2842B, UC2843B, NCV3843BV
2.55 V
V
CC
= 15 V
A
V
= -1.0
T
A
= 25°C
20 mV/DIV
3.0 V
V
CC
= 15 V
A
V
= -1.0
T
A
= 25°C
20 mV/DIV
1.0
µs/DIV
2.50 V
2.5 V
2.45 V
0.5
µs/DIV
2.0 V
Figure 6. Error Amp Small Signal
Transient Response
Figure 7. Error Amp Large Signal
Transient Response
A VOL , OPEN LOOP VOLTAGE GAIN (dB)
100
80
60
40
20
0
100
1.0 k
10 k
Gain
Vth, CURRENT SENSE INPUT THRESHOLD (V)
φ
EXCESS PHASE (DEGREES)
,
V
CC
= 15 V
V
O
= 2.0 V to 4.0 V
R
L
= 100 K
T
A
= 25°C
0
30
60
90
120
150
1.2
1.0
0.8
0.6
0.4
0.2
0
0
2.0
4.0
6.0
V
O
, ERROR AMP OUTPUT VOLTAGE (V)
8.0
V
CC
= 15 V
T
A
= 25°C
T
A
= 125°C
T
A
= -55°C
Phase
- 20
10
100 k
1.0 M
180
10 M
f, FREQUENCY (Hz)
Figure 8. Error Amp Open Loop Gain and
Phase versus Frequency
Figure 9. Current Sense Input Threshold
versus Error Amp Output Voltage
- 4.0
- 8.0
-12
-16
V
CC
= 15 V
90
T
A
= 125°C
T
A
= -55°C
70
- 20
- 24
0
20
T
A
= 25°C
60
40
80
100
120
50
- 55
- 25
0
25
50
75
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
http://onsemi.com
5
ÄÄÄ
ÄÄÄ
100
125
ÄÄÄÄ
ÄÄÄÄ
ÄÄÄ ÄÄÄÄ
ÄÄÄ ÄÄÄÄ
ÄÄÄÄ
0
I SC , REFERENCE SHORT CIRCUIT CURRENT (mA)
∆
Vref , REFERENCE VOLTAGE CHANGE (mV)
110
V
CC
= 15 V
R
L
≤
0.1
Ω
ONSEMI [ ON SEMICONDUCTOR ]
