UC1842A/3A/4A/5A
UC2842A/3A/4A/5A
UC3842A/3A/4A/5A
ELECTRICAL CHARACTERISTICS (cont.) Unless otherwise stated, these specifications apply for -55°C ≤ TA ≤ 125°C for
the UC184xA; -40°C ≤ TA ≤ 85°C for the UC284xA; 0 ≤ TA ≤ 70°C for the UC384xA; VCC = 15V (Note 5); RT = 10k; CT = 3.3nF; TA = TJ;
Pin numbers refer to DIL-8.
UC184xA\UC284xA
UC384xA
PARAMETER
TEST CONDITIONS
UNITS
MIN. TYP. MAX. MIN. TYP. MAX.
Error Amp Section
Input Voltage
Input Bias Current
AVOL
VPIN 1 = 2.5V
2.45
2.50
-0.3
90
1
2.55
-1
2.42 2.50
-0.3
2.58
-2
V
µA
dB
MHz
dB
mA
mA
V
2 ≤ VO ≤ 4V
65
0.7
60
2
65
0.7
60
2
90
1
Unity Gain Bandwidth
PSRR
TJ = 25°C (Note 2)
12 ≤ VCC ≤ 25V
70
6
70
6
Output Sink Current
Output Source Current
VOUT High
VPIN 2 = 2.7V, VPIN 1 = 1.1V
VPIN 2 = 2.3V, VPIN 1 = 5V
VPIN 2 = 2.3V, RL = 15k to ground
VPIN 2 = 2.7V, RL = 15k to Pin 8
-0.5
5
-0.8
6
-0.5
5
-0.8
6
VOUT Low
0.7
1.1
0.7
1.1
V
Current Sense Section
Gain
(Note 3, Note 4)
2.85
0.9
3
1
3.15
1.1
2.85
0.9
3
1
3.15
1.1
V/V
V
Maximum Input Signal
PSRR
VPIN 1 = 5V (Note 3)
12 ≤ VCC ≤ 25V (Note 3)
70
-2
70
-2
dB
µA
ns
Input Bias Current
Delay to Output
Output Section
Output Low Level
-10
-10
VPIN 3 = 0 to 2V (Note 2)
150
300
150
300
ISINK = 20mA
0.1
15
0.4
2.2
0.1
15
0.4
2.2
V
V
ISINK = 200mA
Output High Level
ISOURCE = 20mA
13
12
13.5
13.5
50
13
12
13.5
13.5
50
V
ISOURCE = 200mA
V
Rise Time
TJ = 25°C, CL = 1nF (Note 2)
TJ = 25°C, CL = 1nF (Note 2)
VCC = 5V, ISINK = 10mA
150
150
1.2
150
150
1.2
ns
ns
V
Fall Time
50
50
UVLO Saturation
Under-Voltage Lockout Section
Start Threshold
0.7
0.7
x842A/4A
x843A/5A
x842A/4A
x843A/5A
15
7.8
9
16
8.4
10
17
9.0
11
14.5
7.8
8.5
7.0
16
8.4
10
17.5
9.0
V
V
V
V
Min. Operation Voltage After
TurnOn
11.5
8.2
7.0
7.6
8.2
7.6
PWM Section
Maximum Duty Cycle
x842A/3A
x844A/5A
94
47
96
48
100
50
0
94
47
96
48
100
50
0
%
%
%
Minimum Duty Cycle
Total Standby Current
Start-Up Current
0.3
11
34
0.5
17
0.3
11
34
0.5
17
mA
mA
V
Operating Supply Current
VCC Zener Voltage
VPIN 2 = VPIN 3 = 0V
ICC = 25mA
30
30
Note 2: These parameters, although guaranteed, are not 100%
tested in production.
Note 3: Parameter measured at trip point of latch with VPIN2 = 0.
VREF (max) − VREF (min)
TJ (max) − TJ (min)
VREF (max) and VREF (min) are the maximum & mini-
mum reference voltage measured over the appropriate
temperature range. Note that the extremes in voltage
do not necessarily occur at the extremes in tempera-
ture."
Temp Stability =
.
∆VPIN 1
Note 4: Gain defined as: A =
; 0 ≤ VPIN 3 ≤ 0.8V.
∆VPIN 3
Note 5: Adjust VCC above the start threshold before setting at
15V.
Note 6: Output frequency equals oscillator frequency for the
UC1842A and UC1843A. Output frequency is one half
oscillator frequency for the UC1844A and UC1845A.
Note 7: "Temperature stability, sometimes referred to as average
temperature coefficient, is described by the equation:
Note 8: This parameter is measured with RT = 10kΩ to VREF.
This contributes approximately 300µA of current to the
measurement. The total current flowing into the RT/CT
pin will be approximately 300µA higher than the meas-
ured value.
3
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