UC3842B, UC3843B, UC2842B, UC2843B, NCV3843BV
ELECTRICAL CHARACTERISTICS
(V
CC
= 15 V [Note 1], R
T
= 10 k, C
T
= 3.3 nF. For typical values T
A
= 25°C, for min/max values
T
A
is the operating ambient temperature range that applies [Note 2], unless otherwise noted.)
UC284XB
Characteristics
REFERENCE SECTION
Reference Output Voltage (I
O
= 1.0 mA, T
J
= 25°C)
Line Regulation (V
CC
= 12 V to 25 V)
Load Regulation (I
O
= 1.0 mA to 20 mA)
Temperature Stability
Total Output Variation over Line, Load, and Temperature
Output Noise Voltage (f = 10 Hz to 10 kHz, T
J
= 25°C)
Long Term Stability (T
A
= 125°C for 1000 Hours)
Output Short Circuit Current
OSCILLATOR SECTION
Frequency
T
J
= 25°C
T
A
= T
low
to T
high
T
J
= 25°C (R
T
= 6.2 k, C
T
= 1.0 nF)
Frequency Change with Voltage (V
CC
= 12 V to 25 V)
Frequency Change with Temperature, T
A
= T
low
to T
high
Oscillator Voltage Swing (Peak−to−Peak)
Discharge Current (V
OSC
= 2.0 V)
T
J
= 25°C, T
A
= T
low
to T
high
UC284XB, UC384XB
T
A
= T
low
to T
high
UC384XBV
ERROR AMPLIFIER SECTION
Voltage Feedback Input (V
O
= 2.5 V)
Input Bias Current (V
FB
= 5.0 V)
Open Loop Voltage Gain (V
O
= 2.0 V to 4.0 V)
Unity Gain Bandwidth (T
J
= 25°C)
Power Supply Rejection Ratio (V
CC
= 12 V to 25 V)
Output Current
Sink (V
O
= 1.1 V, V
FB
= 2.7 V)
Source (V
O
= 5.0 V, V
FB
= 2.3 V)
Output Voltage Swing
High State (R
L
= 15 k to ground, V
FB
= 2.3 V)
Low State (R
L
= 15 k to V
ref
, V
FB
= 2.7 V)
UC284XB, UC384XB
UC384XBV
CURRENT SENSE SECTION
Current Sense Input Voltage Gain (Notes 3 and 4)
UC284XB, UC384XB
UC384XBV
Maximum Current Sense Input Threshold (Note 3)
UC284XB, UC384XB
UC384XBV
Power Supply Rejection Ratio (V
CC
= 12 V to 25 V, Note 3)
Input Bias Current
Propagation Delay (Current Sense Input to Output)
A
V
2.85
−
V
th
0.9
−
PSRR
I
IB
t
PLH(In/Out)
−
−
−
1.0
−
70
− 2.0
150
1.1
−
−
−10
300
0.9
0.85
−
−
−
1.0
1.0
70
− 2.0
150
1.1
1.1
−
−10
300
dB
mA
ns
3.0
−
3.15
−
2.85
2.85
3.0
3.0
3.15
3.25
V
V/V
V
FB
I
IB
A
VOL
BW
PSRR
I
Sink
I
Source
V
OH
V
OL
2.45
−
65
0.7
60
2.0
− 0.5
5.0
−
−
2.5
− 0.1
90
1.0
70
12
−1.0
6.2
0.8
−
2.55
−1.0
−
−
−
−
−
−
1.1
−
2.42
−
65
0.7
60
2.0
− 0.5
5.0
−
−
2.5
− 0.1
90
1.0
70
12
−1.0
6.2
0.8
0.8
2.58
− 2.0
−
−
−
−
−
V
−
1.1
1.2
V
mA
dB
MHz
dB
mA
f
OSC
49
48
225
Df
OSC
/DV
Df
OSC
/DT
V
OSC
I
dischg
7.8
7.5
−
8.3
−
−
8.8
8.8
−
7.8
7.6
7.2
8.3
−
−
8.8
8.8
8.8
−
−
−
52
−
250
0.2
1.0
1.6
55
56
275
1.0
−
−
49
48
225
−
−
−
52
−
250
0.2
0.5
1.6
55
56
275
1.0
−
−
%
%
V
mA
kHz
V
ref
Reg
line
Reg
load
T
S
V
ref
V
n
S
I
SC
4.95
−
−
−
4.9
−
−
− 30
5.0
2.0
3.0
0.2
−
50
5.0
− 85
5.05
20
25
−
5.1
−
−
−180
4.9
−
−
−
4.82
−
−
− 30
5.0
2.0
3.0
0.2
−
50
5.0
− 85
5.1
20
25
−
5.18
−
−
−180
V
mV
mV
mV/°C
V
mV
mV
mA
Symbol
Min
Typ
Max
UC384XB, XBV
Min
Typ
Max
Unit
1. Adjust V
CC
above the Startup threshold before setting to 15 V.
2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
T
low
= 0°C for UC3842B, UC3843B; −25°C for UC2842B, UC2843B; −40°C for UC3842BV, UC3843BV
T
high
= +70°C for UC3842B, UC3843B; +85°C for UC2842B, UC2843B; +105°C for UC3842BV, UC3843BV
NCV3843BV: T
low
= −40°C, T
high
= +105°C. Guaranteed by design. NCV prefix is for automotive and other applications requiring site and
change control.
3. This parameter is measured at the latch trip point with V
FB
= 0 V.
4. Comparator gain is defined as: A
V
DV
Output Compensation
DV
Current Sense Input
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