UC1842A/3A/4A/5A
UC2842A/3A/4A/5A
UC3842A/3A/4A/5A
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply for –55°C
≤
T
A
≤
125°C for the
UC184xA; –40°C
≤
T
A
≤
125°C for the UC284xAQ; –40°C
≤
T
A
≤
85°C for the UC284xA; 0
≤
T
A
≤
70°C for the UC384xA; V
CC
= 15V
(Note 5); R
T
= 10k; C
T
= 3.3nF; T
A
= T
J
; Pin numbers refer to DIL-8.
PARAMETER
Under-Voltage Lockout Section
Start Threshold
Min. Operation Voltage After
Turn On
PWM Section
Maximum Duty Cycle
Minimum Duty Cycle
Total Standby Current
Start-Up Current
Operating Supply Current
V
CC
Zener Voltage
TEST CONDITIONS
UC184xA\UC284xA
MIN. TYP. MAX.
15
7.8
9
7.0
94
47
16
8.4
10
7.6
96
48
17
9.0
11
8.2
100
50
0
0.5
17
30
UC384xA
UNITS
MIN. TYP. MAX.
14.5
7.8
8.5
7.0
94
47
16
8.4
10
7.6
96
48
17.5
9.0
11.5
8.2
100
50
0
0.5
17
V
V
V
V
%
%
%
mA
mA
V
x842A/4A
x843A/5A
x842A/4A
x843A/5A
x842A/3A
x844A/5A
V
PIN 2
= V
PIN 3
= 0V
I
CC
= 25mA
30
0.3
11
34
0.3
11
34
Note 2:
Ensured by design, but not 100% production tested.
Note 3:
Parameter measured at trip point of latch with V
PIN2
= 0.
∆
VPIN 1
; 0 V
PIN 3
0.8V.
Note 4:
Gain defined as: A
=
∆
VPIN 3
Note 5:
Adjust V
CC
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
)
.V
REF
(max) and V
REF
(min) are the maximum & minimum reference volt-
Temp Stability
=
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 R
T
= 10k to V
REF
.This contributes approximately 300 A of current to the measurement.
The total current flowing into the R
T
/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
TI [ TEXAS INSTRUMENTS ]
