@vic
AV
3842B / 3843B
LINEAR INTEGRATED CIRCUIT
QW-R103-012,A
HIGH PERFORMANCE CURRENT
MODE CONTROLLERS
DESCRIPTION
Th
e @vic
AV
3842B/3843B are specifically designed for
Off-Line and dc-to-dc converter applications offering the
designer a cost-effective solution with minimal external
components.
The
AV
3842B has UVLO thresholds 16V (on) and 10V(off),
ideally suited for off-line converters. The
AV
3843B is tailored
for lower voltage applications having UVLO thresholds of
8.5V(on) and 7.6V(off).
FEATURES
*Trimmed Oscillator for Precise Frequency Control
*Oscillator Frequency Guaranteed at 250kHz
*Current Mode Operation to 500kHz
*Automatic Feed Forward Compensation
*Latching PWM for Cycle-By-Cycle Current Limiting
*Internally Trimmed Reference with Undervoltage Lockout
*High Current Totem Pole Output
*Undervoltage Lockout with Hysteresis
*Low Startup and Operating Current
DIP-8
SOP-8
BLOCK DIAGRAM
QW-R103-012,A
ABSOLUTE MAXIMUM RATINGS
(Ta=25
C)
PARAMETER SYMBOL
VALUE
UNIT
Total power supply and Zener current
(ICC + Iz)
30
mA
Output current, source or sink (note1)
Io
1.0
A
Output energy (capacitive load per cycle)
W
5.0
J
Current sense and voltage feedback
inputs
Vin
-0.3 ~ +5.5
V
Error Amp. Output sink current
Io
10
mA
Power dissipation and thermal
characteristics
PD
P
JA
DIP:1250 SOP: 702
DIP: 100 SOP: 178
mW
C/W
Operating junction temperature
Tj
+150
C
Operating ambient temperature
TA
0 ~ +70
C
Storage temperature range
Tstg
-65 ~ +150
C
ELECTRICAL CHARACTERISTICS
(0
C <=T
A
<=70
C,V
CC
=15V[note 2],R
T
=10k,C
T
=3.3nF,unless
otherwise specified)
PARAMETER SYMBOL
TEST
CONDITIONS MIN
TYP
MAX
UNIT
Reference Section
Output Voltage
V
REF
Io=1.0mA,Tj=25
C
4.9
5.0 5.1 V
Line Regulation
Regline
Vcc=12V to 25V
2.0
20
mV
Load Regulation
Regload
Io=1.0mA to 20mA
3.0
25
mV
Temperature
Stability
Ts
0.2
mV/
C
Total Output Variation
Vref
Line, Load, Temperature
4.82
5.18
V
Output Noise Voltage
Vn
F=10kHz to 10Hz,Tj=25
C
50 uV
Long Term Stability
S
T
A
=125
C,1000Hrs
5 mV
Output Short Circuit Current
I
SC
-30
-85
-180
mA
Oscillator Section
Frequency
Tj=25
C
TA=0
C to 70C
Tj=25
C (R
T
=6.2k,C
T
=1.0nF)
49
48
225
52
250
55
56
275
kHz
Frequency Change with Voltage f
OSC
/
V
12<=Vcc<=25V
0.2
1.0
%
Frequency Change with
Temperature
f
OSC
/
T
0
C <=T
A
<=70
C
0.5 %
Oscillator Voltage Swing(Peak to
Peak)
VOSC
1.6 V
Discharge Current
Idischg
Tj=25
C
0
C <=T
A
<=70
C
7.8
7.6
8.3 8.8
8.8
mA
Error Amplifier Section
Voltage Feedback Input
V
FB
Vo=2.5V
2.42
2.50
2.58
V
Input Bias Current
I
IB
V
FB
=5.0V
-0.1
-2.0
A
Open Loop Voltage Gain
AVOL
2 <=Vo<=4V
65
90
dB
Unity Gain Bandwidth
BW
Tj=25
C
0.7
1.0 MHz
Power Supply Rejection Ratio
PSRR
I2V<=Vcc<=25V
60
70
dB
Output Sink Current
Isink
Vo=1.1V,V
FB
=2.7V
2.0
12
mA
Output Source Current
Isource
Vo=5.0V,V
FB
=2.3V -0.5
-1.0
mA
Output Voltage Swing High State
V
OH
V
FB
=2.3V, R
L
=15k to GND
5.0
6.2
V
Output Voltage Swing Low State
V
OL
V
FB
=2.7V, R
L
=15k to Vref
0.8
1.1
V
Current Sense section
Current Sense Input Voltage
Gain
Av (note
3,4)
2.85
3.0
3.15
V/V
@vic
AV
3842B / 3843B
LINEAR INTEGRATED CIRCUIT
QW-R103-012,A
PARAMETER SYMBOL
TEST
CONDITIONS MIN
TYP
MAX
UNIT
Maximum Current Sense Input
Threshold
Vth (note
3) 0.9
1.0
1.1
V
Power Supply Rejection Ratio
PSRR
12<=Vcc<=25V (note 3)
70
dB
Input Bias Current
I
IB
-2
-10
A
Propagation Delay
tPLH(In/O
ut)
Current Sense Input to Output
150
300
ns
Output Section
Output Low Voltage
V
OL
Isink=20mA
0.1
0.4
V
Isink=200mA
1.6
2.2
V
Output High Level
V
OH
Isource=20mA 13
13.5
V
Isource=200mA
12
13.4
V
Output Voltage with UVLO
Activated
V
OL
(UVLO)
Vcc=6.0V,Isink=1.0mA
0.1
1.1
V
Output Voltage Rise Time
tr
Tj=25
C,C
L
=1nF
50
150
ns
Output Voltage Fall Time
t
f
Tj=25
C,C
L
=1nF
50
150
ns
Under-Voltage Lockout Section
Startup Threshold
Vth
UTC UC3842B
14.5
16
17.5
V
UTC
UC3843B
7.8
8.4
9
V
Min. Operating Voltage After
Turn-on(Vcc)
V
CC(min)
UTC3842B 8.5
10
11.5
V
UTC3843B
7.0
7.6
8.2
V
PWM Section
Maximum Duty Cycle
DC
(MAX)
94
96
%
Minimum Duty Cycle
DC
(MIN)
0
%
Total Device
Power Startup Supply Current
Icc+Ic
Vcc=6.5V for UC3843B
Vcc=14V for UC3842B
0.3
0.5
mA
Power Operating Supply Current
Icc+Ic
Note2
12
17
mA
Power Supply Zener Voltage
Vz
Icc=25mA
30
36
V
Note 1:Maximum Package power dissipation limits must be observed.
Note 2:Adject Vcc above the Startup threshold before setting to 15V.
Note 3:This parameter is measured at the latch trip point with VFB=0V.
Note 4:Comparator gain is defined as :
V Output Compensation
AV
V Current Sense Input
@vic
AV
3842B / 3843B
LINEAR INTEGRATED CIRCUIT
QW-R103-012,A
TYPICAL PERFORMANCE CHARACTERISTICS
@vic
AV
3842B / 3843B
LINEAR INTEGRATED CIRCUIT
QW-R103-012,A
@vic
AV
3842B / 3843B
LINEAR INTEGRATED CIRCUIT
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