UC3842B, UC3843B, UC2842B, UC2843B
http://onsemi.com
4
ELECTRICAL CHARACTERISTICS (V
CC
= 15 V [Note 7], 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 8], unless otherwise noted.)
UC284XB, UC2843D UC384XB, XBV
Characteristics Symbol Min Typ Max Min Typ Max Unit
CURRENT SENSE SECTION
Current Sense Input Voltage Gain (Notes 5 and 6)
UC2843D, UC284XB, UC384XB
UC384XBV
A
V
2.85
−
3.0
−
3.15
−
2.85
2.85
3.0
3.0
3.15
3.25
V/V
Maximum Current Sense Input Threshold (Note 5)
UC2843D, UC284XB, UC384XB
UC384XBV
V
th
0.9
−
1.0
−
1.1
−
0.9
0.85
1.0
1.0
1.1
1.1
V
Power Supply Rejection Ratio (V
CC
= 12 V to 25 V, Note 5) PSRR − 70 − − 70 − dB
Input Bias Current I
IB
− − 2.0 −10 − − 2.0 −10
mA
Propagation Delay (Current Sense Input to Output) t
PLH(In/Out)
− 150 300 − 150 300 ns
OUTPUT SECTION
Output Voltage
Low State (I
Sink
= 20 mA)
(I
Sink
= 200 mA) UC284XB, UC384XB
UC384XBV, UC2843D
High State (I
Source
= 20 mA) UC284XB, UC384XB
UC384XBV, UC2843D
(I
Source
= 200 mA)
V
OL
V
OH
−
−
−
13
−
12
0.1
1.6
−
13.5
−
13.4
0.4
2.2
−
−
−
−
−
−
−
13
12.9
12
0.1
1.6
1.6
13.5
13.5
13.4
0.4
2.2
2.3
−
−
−
V
Output Voltage with UVLO Activated (V
CC
= 6.0 V, I
Sink
= 1.0 mA) V
OL(UVLO)
− 0.1 1.1 − 0.1 1.1 V
Output Voltage Rise Time (C
L
= 1.0 nF, T
J
= 25°C) t
r
− 50 150 − 50 150 ns
Output Voltage Fall Time (C
L
= 1.0 nF, T
J
= 25°C) t
f
− 50 150 − 50 150 ns
UNDERVOLTAGE LOCKOUT SECTION
Startup Threshold (V
CC
)
UCX842B, BV
UCX843B, BV, D
V
th
15
7.8
16
8.4
17
9.0
14.5
7.8
16
8.4
17.5
9.0
V
Minimum Operating Voltage After Turn−On (V
CC
)
UCX842B, BV
UCX843B, BV, D
V
CC(min)
9.0
7.0
10
7.6
11
8.2
8.5
7.0
10
7.6
11.5
8.2
V
PWM SECTION
Duty Cycle
Maximum UC284XB, UC384XB, UC2843D
Maximum UC384XBV
Minimum
DC
(max)
DC
(min)
94
−
−
96
−
−
−
−
0
94
93
−
96
96
−
−
−
0
%
TOTAL DEVICE
Power Supply Current
Startup (V
CC
= 6.5 V for UCX843B, UC2843D
Startup V
CC
14 V for UCX842B, BV)
(Note 7)
I
CC
+ I
C
−
−
0.3
12
0.5
17
−
−
0.3
12
0.5
17
mA
Power Supply Zener Voltage (I
CC
= 25 mA) V
Z
30 36 − 30 36 − V
5. This parameter is measured at the latch trip point with V
FB
= 0 V.
6. Comparator gain is defined as: A
V
DV Output Compensation
DV Current Sense Input
7. Adjust V
CC
above the Startup threshold before setting to 15 V.
8. 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, UC2843D
T
high
= +70°C for UC3842B, UC3843B; +85°C for UC2842B, UC2843B, UC2843D; +105°C for UC3842BV, UC3843BV
