UC3842B, UC3843B, UC2842B, UC2843B, NCV3843BV
ELECTRICAL CHARACTERISTICS (VCC = 15 V [Note 4], RT = 10 k, CT = 3.3 nF. For typical values TA = 25°C, for min/max values
TA is the operating ambient temperature range that applies [Note 5], unless otherwise noted.)
UC284XB
UC384XB, XBV
Characteristics
Symbol Min Typ Max Min Typ Max Unit
ERROR AMPLIFIER SECTION
Voltage Feedback Input (VO = 2.5 V)
Input Bias Current (VFB = 5.0 V)
Open Loop Voltage Gain (VO = 2.0 V to 4.0 V)
Unity Gain Bandwidth (TJ = 25°C)
Power Supply Rejection Ratio (VCC = 12 V to 25 V)
Output Current
Sink (VO = 1.1 V, VFB = 2.7 V)
Source (VO = 5.0 V, VFB = 2.3 V)
Output Voltage Swing
High State (RL = 15 k to ground, VFB = 2.3 V)
Low State (RL = 15 k to Vref, VFB = 2.7 V)
(UC284XB, UC384XB)
(UC384XBV)
VFB
IIB
AVOL
BW
PSRR
ISink
ISource
VOH
VOL
2.45 2.5 2.55 2.42 2.5 2.58 V
– – 0.1 –1.0 – – 0.1 – 2.0 µA
65
90
–
65
90
–
dB
0.7 1.0
–
0.7 1.0
– MHz
60
70
–
60
70
–
dB
mA
2.0 12
–
2.0 12
–
– 0.5 –1.0 – – 0.5 –1.0 –
V
5.0 6.2
–
5.0 6.2
–
–
0.8 1.1
–
0.8 1.1
–
–
–
–
0.8 1.2
CURRENT SENSE SECTION
Current Sense Input Voltage Gain (Notes 6 & 7)
(UC284XB, UC384XB)
(UC384XBV)
AV
V/V
2.85 3.0 3.15 2.85 3.0 3.15
–
–
– 2.85 3.0 3.25
Maximum Current Sense Input Threshold (Note 6)
(UC284XB, UC384XB)
(UC384XBV)
Vth
V
0.9 1.0 1.1 0.9 1.0 1.1
–
–
– 0.85 1.0 1.1
Power Supply Rejection Ratio (VCC = 12 V to 25 V, Note 6)
PSRR
–
70
–
–
70
–
dB
Input Bias Current
IIB
– – 2.0 –10
– – 2.0 –10 µA
Propagation Delay (Current Sense Input to Output)
tPLH(In/Out)
–
150 300
–
150 300 ns
OUTPUT SECTION
Output Voltage
Low State (ISink = 20 mA)
(ISink = 200 mA)
(UC284XB, UC384XB)
(UC384XBV)
High State (ISource = 20 mA) (UC284XB, UC384XB)
(UC384XBV)
(ISource = 200 mA)
V
VOL
–
0.1 0.4
–
0.1 0.4
–
1.6 2.2
–
1.6 2.2
–
–
–
–
1.6 2.3
VOH
13 13.5 –
13 13.5 –
–
–
– 12.9 13.5 –
12 13.4 –
12 13.4 –
Output Voltage with UVLO Activated (VCC = 6.0 V, ISink = 1.0 mA) VOL(UVLO) –
0.1 1.1
–
0.1 1.1
V
Output Voltage Rise Time (CL = 1.0 nF, TJ = 25°C)
tr
–
50 150
–
50 150 ns
Output Voltage Fall Time (CL = 1.0 nF, TJ = 25°C)
tf
–
50 150
–
50 150 ns
UNDERVOLTAGE LOCKOUT SECTION
Startup Threshold (VCC)
UCX842B, BV
UCX843B, BV
Vth
V
15
16
17 14.5 16 17.5
7.8 8.4 9.0 7.8 8.4 9.0
Minimum Operating Voltage After Turn–On (VCC)
UCX842B, BV
UCX843B, BV
VCC(min)
V
9.0
10
11
8.5
10 11.5
7.0 7.6 8.2 7.0 7.6 8.2
4. Adjust VCC above the Startup threshold before setting to 15 V.
5. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
Tlow = 0°C for UC3842B, UC3843B; –25°C for UC2842B, UC2843B; –40°C for UC3842BV, UC3843BV
Thigh = +70°C for UC3842B, UC3843B; +85°C for UC2842B, UC2843B; +105°C for UC3842BV, UC3843BV
NCV3843BV: Tlow = –40°C, Thigh = +125°C. Guaranteed by design. NCV prefix is for automotive and other applications requiring site and
change control.
6. This parameter is measured at the latch trip point with VFB = 0 V.
7. Comparator gain is defined as: AV
∆V Output Compensation
∆V Current Sense Input
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