UC1842A/3A/4A/5A
UC2842A/3A/4A/5A
UC3842A/3A/4A/5A
ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for –55°C ≤ TA ≤ 125°C for the
UC184xA; –40°C ≤ TA ≤ 125°C for the UC284xAQ; –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.
Under-Voltage Lockout Section
Start Threshold
x842A/4A
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
x843A/5A
x842A/4A
x843A/5A
Min. Operation Voltage After
Turn On
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: Ensured by design, but not 100% production tested.
Note 3: Parameter measured at trip point of latch with VPIN2 = 0.
∆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 fre-
quency for the UC1844A and UC1845A.
Note 7: “Temperature stability, sometimes referred to as average temperature coefficient, is described by the equation:
VREF (max ) −VREF (min)
Temp Stability =
.VREF (max) and VREF (min) are the maximum & minimum reference volt-
TJ (max ) −TJ (min)
age measured over the appropriate temperature range. Note that the extremes in voltage do not necessarily occur at the extremes
in temperature.”
Note 8: This parameter is measured with RT = 10k to VREF.This contributes approximately 300 A of current to the measurement.
The total current flowing into the RT/C pin will be approximately 300 A higher than the measured value.
Error Amp Configuration
Error Amp can Source and Sink up to 0.5mA, and Sink up to 2mA.
4
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