IK Semicon IL3843 Fixed frequency current mode pwm controller Datasheet

TECHNICAL DATA
Fixed Frequency Current Mode PWM Controller
IL3843
DESCRIPTION
Fixed frequency current-mode PWM controller. It is specially designed
for Off Line And DC-to-DC converter applications with minimal external
component. This integrated circuit features a trimmed oscillator for precise
duty cycle control. a temperature compensated reference, high gain arror
amplifier, current sensing comparator, and a high current totempole output
ideally suited for driving a power MOSFET.
Protection circuitry includes built in under-voltage lockout and current
limiting.
ORDERI NG I NFORM ATI ON
IL3843N Plastic
IL3843D SOIC
TA = 0° to 70° C for all packages.
FEATURES
♦ Automatic Feed Forward Compensation
♦High Gain Totem Pole Output
♦Internally Trimmed Bandgap Reference
♦Undervoltage Lockout with Hysteresis
♦Low Start Up Current
♦Optimized for offline converter
♦Double pulse suppression
♦Current mode operation to 500KHz
ORDERING INFORMATION
Device
Operating
Package
Temperature Range
IL3843N
TA=0° to +70°C
DIP-8
IL3843D
TA=0° to +70°C
SOP-8
2011, February, Rev. 03
IL3843
PIN FUNCTION DESCRIPTION
Pin
Function
No.
1 Compensation
Description
This pln is the Error Amplifier output and is made available for loop compensation
This is the inverting input of the Error Amplifier. It is normally connected to the switching
power supply outpul through a resistor divider.
A voltage proportional to inductor current is connected to this input. The PWM uses this.
information to terminate the output switch conduction
2
Voltage Feedback
3
Current Sense
4
RT/CT
The Oscillator frequency and maximum Output duty cycle are programmed by connecting
resistor RT to VREF and capacitor CT to ground. Operation to 500kHz is possible.
5
GND
6
Output
7
Vcc
This pin is the combined conlrol circuitry and power ground
This output directly drives the gate of a power MOSFET. Peak currents up to 1,0A are
sourced and sunk by this pin.
This pin is the positive supply of the control IC.
8
VREF
This is the reference output. It provides chsarging current for capacitor CT through resistor
RT
ABSOLUTE MAXIMUM RATINGS
Characteristic
Symbol
Value
Unit
(ICC+ IZ)
30
mA
Output Current
IO
±1.0
A
Output Energy (Capacitive Load per Cycle)
W
5.0
µJ
Error Amp Output Sink Current
IOE
10
mA
Vin
-0.3 to 5.5
V
PD
0.862
0.625
W
RθJA
145
°C/W
TJ
+150
o
-65 ~ +150
o
Total Power Supply and Zener Current
Current Sense and Voltage Feedback Inputs
o
Maximum Power Dissipation @ TA= 25 C:
DIP-8
SOP-8
Thermal Resistance,Junction-to-Air
Operating Junction Temperature
Storage Temperature Range
Tstg
C
C
* Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device.
These are stress ratings only and functional operation of the device at these or any other conditions beyond those
indicated under “recommended operating conditions” is not implied.
Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
2011, February, Rev. 03
IL3843
ELECTRICAL CHARACTERISTICS (Vcc=15V unless otherwise noted)
Characteristics
REFERENCE SECTION
Reference Output Voltage (IO=1.0mA, VCC=15V,TA=25±10°C)
(IO=1.0mA, VCC=15V,TA= Tlow to Thigh)
Line Regulation
(VCC=12V to 25V,TA=Tlow to Thigh)
Load Regulation (IO=1.0 to 20mA,TA=Tlow to Thigh)
Total Output Variation over Line,Load,Temperature (Note1)
(VCC=12V, IO=1.0mA,TA=Tlow to Thigh)
(VCC=25V, IO=20mA,TA=Tlow to Thigh)
Output Short Circuit Current (VCC=15V)
Symbol
Min
Max
Unit
Vref
4.9
4.865
5.1
5.135
V
Regline
20
mV
Regload
25
mV
Vfinal
4.82
5.18
V
ISC
-30
-180
mA
fosc
47
46
57
60
kHz
1.0
%
7.5
7.2
9.3
9.5
mA
VFB
IIB
2.42
2.58
-2.0
V
µA
AVOL
65
dB
BW
0.7
MHz
PSRR
60
dB
ISink
ISource
2.0
-0.5
mA
VOH
VOL
5.0
Av
2.85
3.15
V/V
Vth
IIB
0.9
1.1
-10
V
µA
300
ns
OSCILLATOR SECTION
Frequency (VCC=15V,Tj=25°C,RT=10k,CT=3.3nF)
(VCC=15V, TA=Tlow to Thigh,RT=10k,CT=3.3nF)
Frequency Change with Voltage
(VCC=12V to 25V, TA=Tlow to Thigh,RT=10k,CT=3.3nF)
Discharge Current (Vosc=2.0V, VCC=15V)
Tj=25°C
TA=Tlow to Thigh
Δfosc/ΔV
Idisch
ERROR AMPLIFIER SECTION
Voltage Feedback Input (VO=2.5V,VCC=15V, TA=Tlow to Thigh)
Input Bias Current (VFB=2.7V,VCC=15V, TA=Tlow to Thigh)
Open Loop Voltage Gain
(VO=2.0V to 4.0V,VCC=15V, TA=Tlow to Thigh)
Unity Gain Bandwidth (VCC=15V, TA=Tlow to Thigh)
Power Supply Rejection Ratio
(VCC=12V to 25V, Vo=3.0V, TA=Tlow to Thigh)
Output Current
Sink (VO=1.1V,VFB=2.7V, VCC=15V, TA=Tlow to Thigh)
Source (VO=5.0V,VFB=2.3V, VCC=15V, TA=Tlow to Thigh)
Output Voltage Swing
High State (VFB=2.3V, VCC=15V,RL(GND)=15k, TA=Tlow to Thigh)
Low State (VFB=2.7V, VCC=15V,RL(5.0)=15k, TA=Tlow to Thigh)
1.1
V
CURRENT SENSE SECTION
Current Sense Input Voltage Gain
(VFB=0V, VCC=15V, TA=Tlow to Thigh)
Maximum Current Sense Input Threshold
(VFB=0V, VCC=15V, TA=Tlow to Thigh)
Input Bias Current (VCC=15V, TA=Tlow to Thigh)
Propagation Delay (Current Sense Input to Output)
(VCC=15V, TA=Tlow to Thigh)
tPLH
2011, February, Rev. 03
IL3843
EL ECTRI CAL CHARACTERI STI CS (Vcc= 15V unless otherwise noted)
Characteristics
OUTPUT SECTION
Output Voltage
Low State (Sink=20mA, VCC=15V)
(Sink=200mA, VCC=15V)
High State (Sink=-20mA, VCC=15V)
(Sink=-200mA, VCC=15V)
Output Voltage with UVLO Activated
(VCC=6.0V, ISink,=1.0mA, TA=Tlow to Thigh)
Symbol
Min
Max
Unit
0.4
2.2
V
1.1
V
tr
150
ns
tf
150
ns
VOL
VOH
13
12
VOL(UVL
O)
Output Voltage Rise Time
(CL=1.0nF, VCC=15V, TA=Tlow to Thigh)
Output Voltage Fall Time
(CL=1.0nF, VCC=15V, TA=Tlow to Thigh)
ONDERVOLTAGE LOCKOUT SECTION
Startup Threshold
(VCC=0V to 15V,TA=Tlow to Thigh)
Minimum Operating Voltage After Turn-On
(VCC=15V to 0V,TA=Tlow to Thigh)
PWM SECTION
Duty Cycle
Maximum (VCC=15V, TA=Tlow to Thigh,RT=10k,CT=3.3nF)
Minimum (VCC=15V, TA=Tlow to Thigh,RT=10k,CT=3.3nF)
TOTAL DEVICE
Power Supply Current
Startup: VCC=6.5V
VCC=15V Operating
Power Supply Zener Voltage
(ICC=25mA, VCC=0 to 40V)
Vth
7.8
9.0
V
VCC(min)
7.0
8.2
V
DCmax
DCmin
94
0
ICC
Vz
30
1.0
17
40
%
mA
V
NOTES: 1. Vfinal= Vref25 ±( Regline+ Regload)/1000± | Vref70(Vref0)-Vref25 |
Vref25=Vref @ TA=25°C;
Vref70=Vref @ TA=70°C;
Vref0 =Vref @ TA=0°C.
2. Tlow= 0°C ; Thigh=+70°C
2011, February, Rev. 03
IL3843
N SUFFIX PLASTIC DIP
(MS – 001BA)
A
Dimension, mm
5
8
B
1
4
F
Symbol
MIN
MAX
A
8.51
10.16
B
6.1
7.11
C
L
C
5.33
D
0.36
0.56
F
1.14
1.78
-T- SEATING
PLANE
N
G
M
K
0.25 (0.010) M
J
H
D
T
NOTES:
1. Dimensions “A”, “B” do not include mold flash or protrusions.
Maximum mold flash or protrusions 0.25 mm (0.010) per side.
G
2.54
H
7.62
J
0°
10°
K
2.92
3.81
L
7.62
8.26
M
0.2
0.36
N
0.38
D SUFFIX SOIC
(MS - 012AA)
Dimension, mm
A
8
5
B
H
1
G
P
4
D
K
MIN
MAX
A
4.8
5
B
3.8
4
C
1.35
1.75
D
0.33
0.51
F
0.4
1.27
R x 45
C
-T-
Symbol
SEATING
PLANE
J
F
0.25 (0.010) M T C M
NOTES:
1. Dimensions A and B do not include mold flash or protrusion.
2. Maximum mold flash or protrusion 0.15 mm (0.006) per side
for A; for B ‑ 0.25 mm (0.010) per side.
M
G
1.27
H
5.72
J
0°
8°
K
0.1
0.25
M
0.19
0.25
P
5.8
6.2
R
0.25
0.5
2011, February, Rev. 03
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