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Электронный компонент: FA13842N

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FA13842, 13843, 13844, 13845
1
s
Description
The FA1384X series are CMOS current mode control ICs for
off-line and DC-to-DC converters.
These ICs can reduce start-up circuit loss and are optimum for
high efficiency power supplies because of the low power
dissipation achieved through changes in the CMOS fabrication
process.
These ICs can drive a power MOSFET directly.
The high-performance, compact power supply can be
designed with minimal external components .
s
Features
CMOS process
Low-power dissipation
Standby current 2
A (max.), start-up current 30
A (max.)
Pulse-by-pulse current limiting
5V bandgap reference
UVLO (Undervoltage lockout) with hysteresis
Maximum duty cycle
FA13842, 13843: 96%
FA13844, 13845: 48%
Pin-for-pin compatible with UC384X
Note:
Pins are fully compatible, but characteristics are not.
When our ICs are applied to a power supply circuit
designed for other manufactures' 384X series, the
characteristics and safety features of the power supply
must be checked.
s
Types of FA1384X series
FA13842,13843,13844,13845
CMOS IC
For Switching Power Supply Control
s
Dimensions, mm
SOP-8
4.9
3.9
6.0
0.2
0.4
0.1
1.27
0.2
0.20
+0.1
0.05
0~8
1
4
8
5
1.7max
DIP-8
1
8
5
4
9.3
6.4
7.62
3.3
4.5max
1.5
3.0min
0~15
0~15
0.46
0.1
2.54
0.25
0.25
+0.1
0.05
Type
UVLO
Maximum duty Package
Start threshold Stop threshold cycle
FA13842P 16.5V
1V
9V
1V
96%
DIP
FA13842N
SOP
FA13843P
9.6V
1V
9V
1V
96%
DIP
FA13843N
SOP
FA13844P 16.5V
1V
9V
1V
48%
DIP
FA13844N
SOP
FA13845P
9.6V
1V
9V
1V
48%
DIP
FA13845N
SOP
FA13842, 13843, 13844, 13845
2
s
Absolute maximum ratings (Ta=25C)
s
Block diagram
FA13842, 13843
FA13844, 13845
VCC
ENB
ENB
2.5V
OUTPUT
5V REF
UVLO
OSC
VCC
30V
RT/CT
FB
COMP
ISNS
GND
OUT
VREF
ER AMP
2R
1R
1V
5V ControlIed block
S
FF
Q
QB
R
TFFQ
QB
CLK
UVLO
7
8
6
5
4
2
1
3
VCC
ENB
ENB
2.5V
OUTPUT
5V REF
UVLO
OSC
VCC
30V
RT/CT
FB
COMP
ISNS
GND
OUT
VREF
ER AMP
2R
1R
1V
5V Controlled block
S
FF
Q
QB
R
UVLO
7
8
6
5
4
2
1
3
I
tem
Symbol
Test condition
Rating
Unit
Supply voltage
V
CC
Low impedance source
28
V
Zener clamp (Icc<10mA)
Self limiting
V
Zener current
I
Z
10
mA
Output peak current
I
O
Source current
400
mA
Sink current
1
A
FB/ISNS terminal input voltage
V
IN
FB, ISNS
0.3 to 5.3
V
Error amplifier sink current
I
SINK
10
mA
Total power dissipation
P
d
at Ta < 50C DIP
800
mW
SOP
400
Thermal resistance
R
j-a
Junction-air DIP
125
C/W
SOP
250
Junction temperature
T
j
150
C
Ambient temperature
T
a
25 to 85
C
Storage temperature
T
stg
40 to 150
C
Pin No. Symbol Function
Description
1
COMP
Compensating
Error amplifier output, available
for loop compensation circuit
2
FB
Feedback
Inverting input of the error
amplifier
3
ISNS
Current sensing
Input voltage proportional to
inductor current
4
RT/CT
Oscillator control
Setting oscillation frequency
and maximum duty-cycle with
resistor R
T
and capacitor C
T
5
GND
Ground
Ground
6
OUT
Output
Output for driving a power
MOSFET
7
VCC
Power supply
Power supply
8
VREF
Reference voltage Reference voltage and
current source charging
capacitor C
T
through resistor
R
T
FA13842, 13843, 13844, 13845
3
Current sensing section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Voltage gain
A
V IS
Tj=25C
2.85
3
3.15
V/V
Maximum input signal
V
TH IS
FB=0V
0.9
1.0
1.1
V
Input bias current
I
IS
1
5
A
Delay to output
T
PD
Tj=25C, ISNS to OUT
150
300
ns
s
Electrical characteristics (Vcc=15V, R
T
=10k
, C
T
=3.3nF, Ta=25C)
Reference voltage section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Reference voltage
V
REF
Tj=25C, I
L
=1mA
4.75
5.00
5.25
V
Line regulation
L
INE
Vcc=10 to 25V
3
20
mV
Load current regulation
L
OAD
I
L
=0 to 20mA
3
25
mV
Temperature regulation
V
TC
Ta=25 to 85C
0.3
mV/C
Output current at short-circuit
I
OS
Tj=25C
60
mA
s
Recommended operating conditions
Item
Symbol
Min.
Max.
Unit
Supply voltage
V
CC
10
25
V
Oscillation timing capacitor
C
T
0.47
10
nF
Oscillation timing resistor
R
T
2.0
100
k
Oscillation frequency
f
OSC
10
500
kHz
Oscillator section
Error amplifier section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Input voltage
V
FB
COMP=2.5V, Tj=25C
2.4
2.5
2.6
V
Input leak current
I
FB
2
A
Open-loop gain
A
V
65
72
dB
Unity gain bandwidth
f
T
0.7
1
MHz
Output source current
I
SOURCE
FB=2.3V, COMP=0V
0.8
1.0
mA
Output sink current
I
SINK
FB=2.7V, COMP=1V
2
15
mA
Output voltage
V
H COMP
FB=2.3V, R
L
=15k
to GND
4.0
4.5
V
V
L COMP
FB=2.7V, R
L
=15k
to VREF
80
500
mV
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Oscillation frequency
f
OSC
Tj=25C
49
52
55
kHz
Ta=25 to 85C
47
57
kHz
Voltage stability
fdv
Vcc=10 to 25V
0.25
1
%
Temperature stability
fdt
Ta=25 to 85C
0.07
%/C
Oscillation amplitude
V
OSC
Tj=25C
1.6
V
Discharge current
I
DISCHG
Tj=25C
8.4
mA
FA13842, 13843, 13844, 13845
4
Output section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
High-level output
V
OH
I source=20mA
14.5
14.75
V
I source=100mA
12
13.5
V
Low-level output
V
OL
I sink=20mA
0.15
0.3
V
I sink=200mA
1.5
3
V
Rise time
tr
C
L
=1nF, Tj=25C
40
150
ns
Fall time
tf
C
L
=1nF, Tj=25C
20
150
ns
Under-voltage lockout section
Overall device
PWM section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Start threshold
V
TH ON
FA13842, 13844
15.5
16.5
17.5
V
FA13843, 13845
8.6
9.6
10.6
V
Min. operating voltage
V
TH OFF
8
9
10
V
Hysteresis
V
HYS
FA13842, 13844
7.5
V
FA13843, 13845
0.6
V
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Maximum duty cycle
Dmax
FA13842, 13843
94
96
98
%
FA13844, 13845
47
48
50
%
Minimum duty cycle
Dmin
FB=5V, COMP=Open
0
%
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Standby current
I
CCL
FA13842, 13844 Vcc=14V
2
A
FA13843, 13845 Vcc=7V
2
A
Start-up current
I
CC ST
Vcc=Start threshold
12
30
A
Operating current
I
CC OP
3
5
mA
Zener voltage (Vcc)
V
Z
Icc=5mA
28
30
34
V
FA13842, 13843, 13844, 13845
5
s
Characteristic curves (Ta=25C)
Timing resistance vs. oscillation frequency
Output dead time vs. oscillation frequency
FA13842, FA13843
FA13842, FA13843
Timing resistance vs. oscillation frequency
Output dead time vs. oscillation frequency
FA13844, FA13845
FA13844, FA13845
RT/CT discharge current vs. temperature
Output max. duty cycle vs. timing resistance
FA13842, FA13843
1
10
100
1000
10
1
100
R
T
resistance (k
)
V
CC
= 15V
Ta= 25C
C
T
=10nF
2.2nF
470pF
Oscillation frequency (kHz)
10
100
1000
10
1
100
Output dead time (%)
V
CC
= 15V
Ta= 25C
C
T
=10nF
2.2nF
470pF
Oscillation frequency (kHz)
V
CC
= 15V
Ta= 25C
C
T
=10nF
2.2nF
470pF
10
1
100
1000
10
1
100
R
T
resistance (k
)
Oscillation frequency (kHz)
V
CC
= 15V
Ta= 25C
C
T
=10nF
2.2nF
470pF
10
100
1000
70
40
50
60
80
90
100
Output dead time (%)
Oscillation frequency (kHz)
50
0
50
100
150
Temperature (C)
RT/CT discharge current (mA)
7
7.5
8
8.5
9
9.5
10
1
10
2
5
R
T
timing resistance (k
)
Output maximum duty cycle (%)
40
50
60
70
80
90
100