CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
1
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
General Description
The AP3842C/3C/4C/5C are high performance fixed
frequency current-mode PWM controller series.
These integrated circuits are optimized for off-line and
DC-DC converter applications with minimum external
components. They feature under-voltage lockout
(UVLO) circuit with low start-up current, trimmed
oscillator for precise duty cycle control, current sense
comparator providing maximum current limiting and a
totem pole output stage for increasing output current.
In addition, these ICs also feature accurate protection
against over-temperature, over-current and maximal
output power.
The AP3842C and AP3844C have UVLO thresholds
of 16V(on) and 10V(off); The corresponding thresh-
olds for AP3843C and AP3845C are 8.4 V(on) and
7.6V(off).
The AP3842C and AP3843C can operate approaching
100% duty cycle; AP3844C and AP3845C can operate
from zero to 50% duty cycle.
These ICs are available in SOIC-8 and DIP-8 pack-
ages.
Features
·Low Start-up Current: 50µA
·Robust VREF Line/Load Regulation
Low Line Regulation : 4mV
Low Load Regulation : 4mV
·High Stability of Reference Voltage over a Full
Temperature Range: 0.2mV/ oC
·Operating Frequency up to 500KHz
·High PWM Frequency Stability over a Full Tem-
perature Range: 2.5%
·High PWM Frequency Stability under a Full Sup-
ply Voltage Range: 0.2%
·Accurate Over-temperature Protection with Hys-
teresis
·UVLO with Hysteresis
Applications
·Off-line Converter
·DC-DC Converter
·Voltage Adapter
·CRT Monitor Power Supply
·Desktop Power Supply
·DVD/STB Power Supply
SOIC-8 DIP-8
Figure 1. Package Types of AP3842C/3C/4C/5C
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
2
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Figure 2. Pin Configuration of AP3842C/3C/4C/5C (Top View)
Pin Configuration
Pin Description
Pin Number Pin Name Function
1 COMP This pin is the Error Amplifier output and is made available for loop compensation.
2V
FB The inverting input of the Error Amplifier. It is normally connected to the switching
power supply output through a resistor divider.
3I
SENSE A voltage proportional to inductor current is connected to this input. The PWM uses
this information to terminate the output switch conduction.
4R
T/CT The Oscillator frequency and maximum output duty cycle are programmed by con-
necting resistor RT to VREF and capacitor CT to ground. Operation to 500 kHz is possi-
ble.
5 GND The combined control circuitry and power ground.
6 OUTPUT This output directly drives the gate of a power MOSFET. Peak currents up to 1.0 A are
sourced and sunk by this pin.
7V
CC The positive supply of the control IC.
8V
REF This is the reference output. It provides charging current for capacitor CT through
resistor RT.
COMP
ISENSE
VFB
RT/CT
VREF
VCC
GND
OUTPUT
1
2
3
4
8
7
6
5
M Package
(SOIC-8)
P Package
(DIP-8)
1
2
3
4
8
7
6
5
COMP
ISENSE
VFB
RT/CT
VREF
VCC
GND
OUTPUT
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
3
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Functional Block Diagram
Figure 3. Functional Block Diagram of AP3842C/3C/4C/5C
VCC
GND
RT/CT
VFB
ISENSE
COMP
VREF
OUTPUT
OSC
VREF
GOOD
LOGIC
OVER TEMP
PROTECT
T
INTERNAL
BIAS
2R
R
S/R 5V
REF
UVLO
2.50V
PWN
LATCH
CURRENT
SENSE
COMPARATOR
ERROR
AMP
34V
1V
7
5
4
2
1
3
8
6
S
R
Note: Toggle flip-flop used
for 3844C/45C only
(Note)
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
4
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Package Tempera-
ture Range
Part Number Marking ID Packing
Type
Lead Free Green Lead Free Green
SOIC-8
-40 to 85oC
AP3842/3/4/5CM-E1 AP3842/3/4/5CM-G1 3842/3/4/5CM-E1 3842/3/4/5CM-G1 Tube
AP3842/3/4/5CMTR-E1 AP3842/3/4/5CMTR-G1 3842/3/4/5CM-E1 3842/3/4/5CM-G1 Tape & Reel
DIP-8 AP3842/3/4/5CP-E1 AP3842/3/4/5CP-G1 AP3842/3/4/5CP-E1 AP3842/3/4/5CP-G1 Tube
Circuit Type
Package
P: DIP-8
M: SOIC-8
E1: Lead Free
AP384XC -
TR: Tape and Reel
Blank: Tube
Ordering Information
G1: Green
BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant. Products with
"G1" suffix are available in green packages.
2: AP3842C
3: AP3843C
4: AP3844C
5: AP3845C
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
5
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Parameter Symbol Value Unit
Supply Voltage VCC 30 V
Output Current IO± 1 A
Analog Inputs V(ANA) -0.3 to 6.3 V
Error Amp Output Sink Current ISINK(E.A) 10 mA
Power Dissipation at TA< 25 oC (DIP-8) PD (Note 3) 1000 mW
Power Dissipation at TA<25 oC (SOIC-8) PD (Note 3) 460 mW
Junction Operating Temperature TJ-40 to 150 oC
Thermal Resistance (Junction to Ambient)
DIP-8
RθJA
140 oC/W
SOIC-8 160 oC/W
Storage Temperature Range TSTG -65 to 150 oC
Lead Temperature (Soldering, 10sec) TLEAD +300 oC
ESD (Machine Mode) 250 V
Note 1: Stresses greater than 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 indi-
cated under "Recommended Operating Conditions" is not implied. Exposure to "Absolute Maximum Ratings" for extended
periods may affect device reliability.
Note 2: All voltages are with respect to pin 5 and all currents are positive into specified terminal.
Note 3: Board thickness 1.6mm, board dimension 90mm x 90mm.
Parameter Symbol Min Max Unit
Oscillation Frequency f 500 KHz
Ambient Temperature TA -40 85 oC
Recommended Operating Conditions
Absolute Maximum Ratings (Note 1, 2)
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
6
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Parameter Symbol Conditions Min Typ Max Unit
REFERENCE SECTION
Reference Output Voltage VREF TJ=25oC, IREF=1mA 4.90 5.00 5.10 V
Total Output Variation Line, Load, Temp. 4.82 5.18 V
Line Regulation ∆VREF 12V ≤ VCC ≤25V 4 15 mV
Load Regulation ∆VREF 1mA ≤ IREF ≤20mA 4 15 mV
Short Circuit Output Current ISC TA=25oC-100 -180 mA
Temperature Stability 0.2 0.4 mV/oC
OSCILLATOR SECTION
Oscillation Frequency f TJ=25oC47 52 57 KHz
Oscillator Amplitude VOSC Pin 4, peak to peak (Note 6) 1.7 V
Temperature Stability (Note 6) 2.5 %
Voltage Stability 12V ≤ VCC ≤ 25V 0.2 1 %
Discharge Current Vpin 4 =2V(Note 7) 8.5 9.5 10.5 mA
ERROR AMPLIFIER SECTION
Input Voltage VIVpin 1=2.5V 2.45 2.50 2.55 V
Output Sink Current ISINK Vpin1=1.1V 5 8 mA
Output Source Current ISOURCE Vpin1=5V -0.5 -0.8 mA
High Output Voltage VOH RL=15kΩ to GND 5 7 V
Low Output Voltage VOL RL=15kΩ to pin 8 0.7 1.1 V
Voltage Gain 2V ≤ VO ≤ 4V 65 90 dB
Power Supply Rejection Ratio PSRR 12V ≤ VCC ≤ 25V 60 70 dB
CURRENT SENSE SECTION
Maximum Input Signal VI(MAX) Vpin1=5V(Note 4) 0.9 1 1.1 V
Gain GV (Note 4, 5) 2.85 3 3.15 V/V
Power Supply Rejection Ratio PSRR 12V ≤ VCC ≤ 25V (Note 4, 6) 70 dB
Delay to Output Vpin3 = 0 to 2V (Note 6) 150 300 ns
Input Bias Current IBIAS -3 -10 µA
OUTPUT SECTION
Low Output Voltage VOL
ISINK = 20mA 0.1 0.4 V
ISINK = 200mA 1.4 2.2 V
High Output Voltage VOH
ISOURCE = 20mA 13 14 V
ISOURCE = 200mA 12 13 V
Rise Time tRTJ=25oC, CL=1nF (Note 6) 50 150 ns
Fall Time tFTJ=25oC, CL=1nF (Note 6) 50 150 ns
(VCC=15V, RT=10kΩ CT=3.3nF, TA= -40 to 85oC, unless otherwise specified.)
Electrical Characteristics
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
7
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Electrical Characteristics (Continued)
Parameter Symbol Conditions Min Typ Max Unit
UNDER -VOLTAGE LOCKOUT SECTION
Start Threshold VTH(ST) AP3842C/AP3844C 15 16 17 V
AP3843C/AP3845C 7.8 8.4 9.0 V
Min. Operation Voltage
(After Turn On)
VOPR
(Min.)
AP3842C/AP3844C 8.5 10.0 11.5 V
AP3843C/AP3845C 7.0 7.6 8.2 V
PWM SECTION
Max. Duty Cycle D(Max.) AP3842C/AP3843C 95 97 100 %
D(Max.) AP3844C/AP3845C 46 48 50 %
Min. Duty Cycle D(Min.) 0 %
TOTAL STANDBY CURRENT SECTION
Start-Up Current IST 50 80 µA
Operating Supply Current ICC(OPR) Vpin3=Vpin2=0V 8 12 mA
Zener Voltage VZICC=25mA 30 34 V
OVER-TEMPERATURE PROTECT SECTION
Shutdown Temperature TSHUT (Note 6) 155 oC
Temperature Hysteresis THYS (Note 6) 25 oC
Figure 4. Basic Test Circuit
A= , 0 ≤ Vpin3 ≤ 0.8V
∆VPin 3
Note 5: Here gain is defined as:
∆VPin 1
Note 6: These parameters, although guaranteed, are not 100% tested in production.
Note 7: This parameter is measured with RT=10kΩ to VREF, it contributes 0.3mA of current to the measured value.
So the total current flowing into the CT pin will be 0.3mA higher than the measured value approximately.
Note 4: Parameters are tested at trip point of latch with Vpin2 = 0.
1
2
8
7
AP384XC
3
45
6
VREF
VCC
OUTPUT
GND
RT/CT
ISENSE
VFB
COMP
VREF
VCC
OUTPUT
GND
1K
1W
CT
5k
ISENSE
ADJUST
1k
ERROR AMP
ADJUST
4.7k
100k
2N2222
4.7k
RT
0.1µF
0.1µF
A
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
8
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Figure 4 is the basic test circuit for AP384XC. In testing, the high peak currents associated with capacitive loads
necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to pin 5 in a
single point ground. The transistor and 5k potentiometer are used to sample the oscillator waveform and apply an
adjustable ramp to pin 3.
Figure 7. Reference Voltage vs. Ambient Temperature
Typical Performance Characteristics
Figure 5. Oscillator Dead Time vs. Timing Capacitor
Figure 6. Timing Resistor vs. Frequency
ELectrical Characteristics (Continued)
Figure 8. Output Saturation Characteristics
-40 -20 0 20 40 60 80 100 120
4.980
4.985
4.990
4.995
5.000
5.005
5.010
5.015
VCC=15V, IO=1mA
Reference Voltage (V)
Ambient Temperature (oC)
0 50 100 150 200 250 300 350 400 450 500 550 600
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
VCC=15V, TA=25oC
Saturation Voltage (V)
Output Sink Current (mA)
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
9
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Typical Performance Characteristics (Continued)
Figure 9. Error Amplifier Open-Loop Frequency Response Figure 10. Start-up Current vs. Ambient Temperature
10 100 1k 10k 100k 1M
0
10
20
30
40
50
60
70
80
90
Voltage Gain (dB)
Frequency (Hz)
VCC=15V, TA=25oC
-40-20 0 20406080100120
20
30
40
50
60
Start-up Current (µA)
Ambient Temperature (oC)
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
10
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Figure 11. Typical Application of AP3842C/3C/4C/5C
Typical Application
+
8
4
6
3
+
+
J1
AC 90 to 265V
Bridge Diode
1N4007*4
R2
1M/
0.25W
C14
100µ/400V
C2
0.01µ
600V
R3
39k
2W
D1
Byv26e
T
D3
8TQ100
L3
10µ
C9
2200µ
C10
1000µ
C11
1µ
R20
2K
Z2
SA12A
J2
12V/5A
C1 47µR4 10
D2
1N4001
U1
AP3842C/3C/4C/5C
Vcc
7
2
1
5
VCC VREF
VFB RT/CT
COMP OUTPUT
GND ISENSE
U2 PC817
C5
220p
R14
130k
R13
15k
R12
100
Z1
1N5819
R7
1k
R6
20
Q1
IRF830
R9
7.5k
R10
0.51/1W
C6
2200p/600V
R5
10k
C8
0.22µ
R15
100
R16
8.2k
W1
1k R18
3.9k
R17
2k
U3
AZ431
NTC
C3
0.1µ
C4
3.3n
+
R11
820
C7
680p
C15
100p
R19
10
C15
2.2n
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
11
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Mechanical Dimensions
SOIC-8 Unit: mm(inch)
0°
8°
1°
5°
R0.150(0.006)
R0.150(0.006)
1.000(0.039)
0.330(0.013)
0.510(0.020)
1.350(0.053)
1.750(0.069)
0.100(0.004)
0.300(0.012)
0.900(0.035)
0.800(0.031)
0.200(0.008)
3.800(0.150)
4.000(0.157)
7°
7°
20:1
D
1.270(0.050)
TYP
0.190(0.007)
0.250(0.010)
8°
D
5.800(0.228)
6.200(0.244)
0.675(0.027)
0.725(0.029)
0.320(0.013)
8°
0.450(0.017)
0.800(0.031)
4.700(0.185)
5.100(0.201)
Note: Eject hole, oriented hole and mold mark is optional.
CURRENT MODE PWM CONTROLLER AP384XC
Data Sheet
12
Nov. 2009 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
Mechanical Dimensions (Continued)
Unit: mm(inch)DIP-8
4°
6°
R0.750(0.030)
0.254(0.010)TYP
0.130(0.005)MIN
8.200(0.323)
9.400(0.370)
0.204(0.008)
0.360(0.014)
7.620(0.300)TYP
4°
6°
5°
0.700(0.028)
9.000(0.354)
9.400(0.370)
3.710(0.146)
4.310(0.170)
3.000(0.118)
3.600(0.142)
0.360(0.014)
0.560(0.022)
2.540(0.100) TYP
6.200(0.244)
6.600(0.260)
3.200(0.126)
3.600(0.142)
0.510(0.020)MIN
Φ3.000(0.118)
Depth
0.100(0.004)
0.200(0.008)
1.524(0.060) TYP
Note: Eject hole, oriented hole and mold mark is optional.
IMPORTANT NOTICE
BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifi-
cations herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility fo r use of any its products for any
particular purpose, nor does BCD Semiconductor Man ufacturing Limited assume any liability arising out of the application or use
of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
other rights nor the rights of others.
- Wafer Fab
Shanghai SIM-BCD Semiconductor Manufacturing Limited
800, Yi Shan Road, Shanghai 200233, China
Tel: +86-21-6485 1491, Fax: +86-21-5450 0008
BCD Semiconductor Manufacturing Limited
MAIN SITE
REGIONAL SALES OFFICE
Shenzhen Office
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd. Shenzhen Office
Advanced Analog Circuits (Shanghai) Corporation Shenzhen Office
Room E, 5F, Noble Center, No.1006, 3rd Fuzhong Road, Futian District, Shenzhen 518026, China
Tel: +86-755-8826 7951
Fax: +86-755-8826 7865
Taiwan Office
BCD Semiconductor (Taiwan) Company Limited
4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei,
Taiwan
Tel: +886-2-2656 2808
Fax: +886-2-2656 2806
USA Office
BCD Semiconductor Corporation
30920 Huntwood Ave. Hayward,
CA 94544, U.S.A
Tel : +1-510-324-2988
Fax: +1-510-324-2788
- IC Design Group
Advanced Analog Circuits (Shanghai) Corporation
8F, Zone B, 900, Yi Shan Road, Shanghai 200233, China
Tel: +86-21-6495 9539, Fax: +86-21-6485 9673
BCD Semiconductor Manufacturing Limited
http://www.bcdsemi.com
BCD Semiconductor Manufacturing Limited
IMPORTANT NOTICE
BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifi-
cations herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility for use of any its products for any
particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use
of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
other rights nor the rights of others.
- Wafer Fab
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd.
800 Yi Shan Road, Shanghai 200233, China
Tel: +86-21-6485 1491, Fax: +86-21-5450 0008
MAIN SITE
REGIONAL SALES OFFICE
Shenzhen Office
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd., Shenzhen Office
Unit A Room 1203, Skyworth Bldg., Gaoxin Ave.1.S., Nanshan District, Shenzhen,
China
Tel: +86-755-8826 7951
Fax: +86-755-8826 7865
Taiwan Office
BCD Semiconductor (Taiwan) Company Limited
4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei,
Taiwan
Tel: +886-2-2656 2808
Fax: +886-2-2656 2806
USA Office
BCD Semiconductor Corp.
30920 Huntwood Ave. Hayward,
CA 94544, USA
Tel : +1-510-324-2988
Fax: +1-510-324-2788
- Headquarters
BCD Semiconductor Manufacturing Limited
No. 1600, Zi Xing Road, Shanghai ZiZhu Science-based Industrial Park, 200241, China
Tel: +86-21-24162266, Fax: +86-21-24162277
