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June 2005 rev 0.6
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER Voltage Mode PWM Controller with EMI Reduction
General Description
ASM8P18xx is a high performance, adjustable frequency, PWM controller with an integrated spread spectrum modulator for EMI reduction. It contains all the functions of a standard PWM controller along with a user configurable spread spectrum modulation with adjustable spread. ASM8P18xx allows significant system cost savings by reducing the number of PCB layers and shielding that are traditionally required to pass EMI regulation. ASM8P18xx is the industry's first general purpose EMI reduction IC, specifically designed for use in SMPS systems. ASM8P18xx is compatible to any other 3842 PWM controllers. ASM8P18xx is capable of driving 1A maximum current output and it covers a wide supply voltage range from 7V DC to 30V DC. The PWM frequency is selectable from 40 KHz to 400 KHz. ASM8P18xx provides under voltage lockout, thermal shutdown, overload, and undercurrent protection. It is available in 8-pin MicroSO, P-DIP and SOIC package.
Features
30V maximum operating voltage with CMOS technology Adjustable PWM frequencies (40 KHz to 400 KHz) Maximum Output drive current of 1A. Wide duty cycle range (0% minimum to 95% maximum) Spread spectrum modulation with adjustable spread. Under voltage lockout with hysteresis. Low startup current: 275?A maximum Pin compatible with industry standard 3842 PWM controller. Temperature range -40C to +85C. Thermal protection. Frequency skip mode. Available in 8-pin plastic MicroSO, P-DIP and SOIC packages. shutdown, overload and undercurrent
Applications
Off-line converter DC-DC converter Monitor power supply Computer/DVD/STB power supply Wireless base station power supply Telecom power supply
Typical Operating Circuit
VDD VDD FSEL CT GND ASM8P18xx VREF RD COMP FB OUT ISNS R1 RC CC R2 R3 RS VIN
From SMPS Output
Alliance Semiconductor 2575 Augustine Drive * Santa Clara, CA * Tel: 408.855.4900 * Fax: 408.855.4999 *
Notice: The information in this document is subject to change without notice.
June 2005 rev 0.6
Logic Block Diagram
VDD VREF
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
ISNS FSEL
OL + UC SENSE
PWM
SS MOD Control
DRIVER
OUT
UVLO
VBG
THERMAL SHUTDOWN
Error Amp
FB
GND
COMP
Pin Diagram
8-Pin MicroSO, P-DIP and SOIC
COMP FB ISNS FSEL
1 2 3 4
8
VREF VDD OUT GND
COMP FB ISNS FSEL
1 2
8
RD VDD OUT GND
ASM8P18S42 ASM8P1843
7 6 5
ASM8P18S42ER 7 ASM8P18S43ER 3 ASM8P18S44ER 6 ASM8P18S45ER
4 5
Pin Description
Pin # 1 2 3 4 5 6 7 8 Pin Name COMP FB ISNS FSEL GND OUT VDD VREF/ RD Function Input of the PWM Comparator and output of the error amplifier Feedback, inverting input of the error amplifier Current sense comparator input External capacitor selects PWM frequency Ground SS modulated PWM output Supply voltage 5V output for ASM8PI8S42 and ASM8PI843 parts. External resistor "RD" to GND sets the modulation spread for the parts with ER suffix.
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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Application Information
Spread Spectrum Deviation The deviation can be determined by selecting the proper resistor at VREF to GND for the parts with `ER' suffix. (Refer "RD Resistor Vs. % Modulation Depth Plot" for resistor selection) PWM Frequency The PWM frequency can be determined by selecting the proper capacitance (CT) at the FSEL pin. Start-up Current ASM8P18xx allows a substantial reduction in the start up current. Low start up current allows high resistance, lower wattage start-up resistor, to supply controller start up power. Under Voltage Lockout (UVLO) When the power supply voltage is below the start up threshold voltage, internal circuitry puts the output into low impedance state and sets the output to zero.
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
Thermal Shutdown The output of ASM8P18xx goes down to zero when the junction temperature of the device rises above 155C. The device automatically resumes operation when temperature drops to 126C. This protects the device from thermal breakdown. Overload and under current protection ASM8P18xx provides Cycle by cycle current limit and pulls down PWM output to low as soon as ISNS pin senses a peak voltage of 1V, with a delay to output of 125 nS maximum. At no load condition when the device senses the peak voltage level of less than 0.1V at ISNS pin for a period of 200mS, the oscillator enters in to cycle skip mode. Normal condition is restored once ISNS increases beyond 0.1V for more than three cycles. Details of cycle skip for different options are provided in the Electrical Characteristics table.
Absolute Maximum Ratings Symbol
VDD IDD IOUT ISNS VREF VOSC VOUT Supply Voltage Supply Current Maximum Output Current Current Sense Inputs and feedback ISNS, FB, COMP Reference Voltage Oscillator Voltage Output Voltage Operation Junction Temperature Storage Temperature Lead Soldering Temperature (10 Seconds) Static Discharge Voltage MIL-STD-883
*Maximum output voltage = 30V
Parameter
Min
Max
30 TBD* 1 5 6 4 30
Units
V mA A V V V V C C C KV
-45 -65
150 150 300 2
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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Electrical Characteristics
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
Unless otherwise noted, VDD=15V, Capacitor on FSEL = 330pf, ISENS = 0.5V. Specifications are over the -40C to +85C ambient temperature range. Typical values are at 25C.
Parameter
REFERENCE SECTION ASM8P18S42 & ASM8P1843 Output voltage Line Regulation Total Reference variation Temperature Stability Load Regulation (ASM8P1843) ERROR AMPLIFIER SECTION Input Bias Current Input Voltage Open Loop Voltage Gain Power Supply Rejection Ratio Output Sink Current Output Source Current High Output Voltage Low Output Voltage CURRENT SENSE SECTION Over Current Protection Threshold Delay to output Under Current Sense Period Under Current Recovery Period
Symbol
Conditions
Min
Typ
Max
Units
VREF N VREF
TA = +25C, IOUT = 1mA 12V < VDD < 18V, IOUT = 5?A Line, Temperature
4.90
5.00 25
5.1
V mV
0.7 0.5
% mV/C mV
TCREF ImA < Io < 20mA
25
IBIAS VI AVOL PSRR IOL IOH VOH VOL VSTART < VCC < VCC max VFB = 1.32V, VCOMP = 0.15V VFB = 1.18V, VCOMP = 4.17V VFB = 1.25V, RL = 15KP VFB = 1.25V 4.17 Vpin1 = 1.25V 1.2
-20 1.25 65 80 -1.5 0.3 1.3
?A V dB dB mA mA V
0.15
V
VI(MAX) TPD TUCS TUCSD Cycle Skip condition: ISENS R 0.1V
FB = 0V (VCOMP = 5V) VFB = 0V, ISNS = 0 to 2V
0.90
1.00
1.10 125
V ns ms Cycles of PWM Frequency
200 3 ASM8P18S42, ASM8P18S42ER ASM8P1843 ASM8P18S43ER ASM8P18S44ER ASM8P18S45ER 1/4 1/10 No Skip 0.128 0.470 14.71 13.77 6.5 2.5
Cycle Skip
x fS
OUTPUT SECTION Low Output Voltage High Output Voltage On Resistance, High On Resistance, Low VOL VOH RDS(ON)H RDS(ON)L ISINK = 50mA ISINK = 200mA ISOURCE = 50mA ISOURCE = 200mA ISOURCE = 0.2A ISINK = 0.2A At VDD =15V V V P P
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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June 2005 rev 0.6
Parameter
Rise Time Fall Time Shoot Through Current UVLO SECTION ASM8P1843, ASM8P18S43ER, ASM8P18S45ER, ASM8P18S42, ASM8P18S42ER ASM8P18S44ER ASM8P1843, ASM8P18S43ER, ASM8P18S45ER ASM8P18S42, ASM8P18S42ER, ASM8P18S44ER
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
Symbol
tR tF
Conditions
TA = 25C, CL=1nF TA = 25C, CL=1nF
Min
30 30
Typ
Max
Units
nS nS
0
7.8 V 15.4 6.7 10.2 V
Start threshold
Vth(START)
Stop Threshold
Vth(STOP)
PWM SECTION PWM frequency fS ASM8P18S44ER, ASM8P18S45ER Duty Cycle Range ASM8P18S42, ASM8P18S42ER, ASM8P1843, ASM8P18S43ER IST IOUT(PK) ICC(OPR) VZ VFB = 0; ISNS = 0.5; VDD = 15V Junction Temp 1000 5 155 126 ASM8P18S43ER, ASM8P18S45ER ASM8P18S42, ASM8P18S42ER, ASM8P18S44ER 6 40 0 400 50 % 0 95 kHz
TOTAL DEVICE Start up Current Peak Output Current Operating Current Thermal Shutdown Thermal Recovery SPREAD SPECTRUM SECTION 1/20 1/10 of Switching Frequency (KHz) 275 ?A mA mA C C
Modulation Rate
Modulation Depth OSCILLATOR SECTION Frequency change with Voltage Oscillator Amplitude Temperature Stability TOSC Df/d VCC
Refer RD Resistor Vs. % Modulation Depth Plot
0.04
0.05 1.66
% V (Pk-Pk) %/C
0.1
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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Frequency Selection Curve
700 600 500 FS(KHZ) 400 300 200 100 0 15 30 47 62 100 Ct (pF) 147
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
220
330
550
RD Resistor vs % Modulation Depth Plot
16 14 12 +/-MD (% of Fs) 10 8 6 4 2 0 0.51 fS=400KHZ fS=40KHz
1
2.2
6.8
10
20
RD (M Ohms)
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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June 2005 rev 0.6
Package Information 8-lead MSOP Package
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
Dimensions Symbol Min
A A1 A2 b C D e E1 E L U S 0.032 0.002 0.030
Inches Max
0.044 0.006 0.038
Millimeters Min Max
0.81 0.05 0.76 0.30 BSC 0.10 2.90 0.65 BSC 2.90 4.67 0.41 0 0.52 BSC 3.10 5.08 0.66 6 0.20 3.10 1.10 0.15 0.97
0.012 BSC 0.004 0.114 0.008 0.122
0.0256 BSC 0.114 0.184 0.016 0 0.122 0.200 0.026 6
0.0206 BSC
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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June 2005 rev 0.6
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
8-lead (150-mil) SOIC Package
E
H
D
A2
A C
e B
A 1
D
L
Dimensions Symbol Min
A1 A A2 B C D E e H L U 0.004 0.053 0.049 0.012 0.007
Inches Max
0.010 0.069 0.059 0.020 0.010
Millimeters Min Max
0.10 1.35 1.25 0.31 0.18 4.90 BSC 3.91 BSC 1.27 BSC 6.00 BSC 0.41 0 1.27 8 0.25 1.75 1.50 0.51 0.25
0.193 BSC 0.154 BSC 0.050 BSC 0.236 BSC 0.016 0 0.050 8
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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8-lead PDIP Package
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
Dimensions Symbol Min
A A1 A2 b b2 C D E E1 e eB L 0.115 0.015 0.115 0.014 0.045 0.008 0.355 0.300 0.240 0.195 0.022 0.070 0.014 0.400 0.325 0.280
Inches Max
0.210
Millimeters Min Max
5.33 0.38 2.92 0.36 1.14 0.20 9.02 7.62 6.10 2.54 BSC 10.92 2.92 3.81 4.95 0.56 1.78 0.36 10.16 8.26 7.11
0.10 BSC 0.430 0.150
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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Ordering Information
ASM Ordering Part Number ASM8I18S42ERF-08-Px ASM8I18S42ERF-08-Mx ASM8I18S42ERF-08-Sx ASM8P18S42ERF-08-Px ASM8P18S42ERF-08-Mx ASM8P18S42ERF-08-Sx ASM8I18S43ERF-08-Px ASM8I18S43ERF-08-Mx ASM8I18S43ERF-08-Sx ASM8P18S43ERF-08-Px ASM8P18S43ERF-08-Mx ASM8P18S43ERF-08-Sx ASM8I18S44ERF-08-Px ASM8I18S44ERF-08-Mx ASM8I18S44ERF-08-Sx ASM8P18S44ERF-08-Px ASM8P18S44ERF-08-Mx ASM8P18S44ERF-08-Sx ASM8I18S45ERF-08-Px ASM8I18S45ERF-08-Mx ASM8I18S45ERF-08-Sx ASM8P18S45ERF-08-Px ASM8P18S45ERF-08-Mx ASM8P18S45ERF-08-SX ASM8I18S42F-08-Px ASM8I18S42F-08-Mx ASM8I18S42F-08-Sx ASM8P18S42F-08-Px ASM8P18S42F-08-Mx ASM8P18S42F-08-Sx ASM8I1843F-08-Px ASM8I1843F-08-Mx ASM8I1843F-08-Sx ASM8P1843F-08-Px ASM8P1843F-08-Mx ASM8P1843F-08-Sx Package 8-PDIP 8-SOIC 8-PDIP 8-MSOP 8-SOIC 8-PDIP 8-SOIC 8-PDIP 8-MSOP 8-SOIC 8-PDIP 8-SOIC 8-PDIP 8-MSOP 8-SOIC 8-PDIP 8-SOIC 8-PDIP 8-MSOP 8-SOIC 8-PDIP 8-SOIC 8-PDIP 8-MSOP 8-SOIC 8-PDIP 8-SOIC 8-PDIP 8-MSOP 8-SOIC
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
Operating Minimum Maximum Modulation Peak Start-up Package Top Temp Operating Duty Depth Output Voltage Mark Range Voltage Cycle Control Current -45 to 85C -45 to 85C 0 to 70C 0 to 70C 0 to 70C -45 to 85C -45 to 85C 0 to 70C 0 to 70C 0 to 70C -45 to 85C -45 to 85C 0 to 70C 0 to 70C 0 to 70C -45 to 85C -45 to 85C 0 to 70C 0 to 70C 0 to 70C -45 to 85C -45 to 85C 0 to 70C 0 to 70C 0 to 70C -45 to 85C -45 to 85C 0 to 70C 0 to 70C 0 to 70C 15.4V 15.4V 15.4V 15.4V 15.4V 15.4V 7.8V 7.8V 7.8V 7.8V 7.8V 7.8V 15.4V 15.4V 15.4V 15.4V 15.4V 15.4V 7.8V 7.8V 7.8V 7.8V 7.8V 7.8V 15.4V 15.4V 15.4V 15.4V 15.4V 15.4V 7.8V 7.8V 7.8V 7.8V 7.8V 7.8V 10.2V 10.2V 10.2V 10.2V 10.2V 10.2V 6.7V 6.7V 6.7V 6.7V 6.7V 6.7V 10.2V 10.2V 10.2V 10.2V 10.2V 10.2V 6.7V 6.7V 6.7V 6.7V 6.7V 6.7V 10.2V 10.2V 10.2V 10.2V 10.2V 10.2V 6.7V 6.7V 6.7V 6.7V 6.7V 6.7V 95 95 95 95 95 95 95 95 95 95 95 95 50 50 50 50 50 50 50 50 50 50 50 50 95 95 95 95 95 95 95 95 95 95 95 95 External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R External R NA NA NA NA NA NA NA NA NA NA NA NA 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 8I18S42ERF 8I18S42ERF 8I18S42ERF 8P18S42ERF 8P18S42ERF 8P18S42ERF 8I18S43ERF 8I18S43ERF 8I18S43ERF 8P18S43ERF 8P18S43ERF 8P18S43ERF 8I18S44ERF 8I18S44ERF 8I18S44ERF 8P18S44ERF 8P18S44ERF 8P18S44ERF 8I18S45ERF 8I18S45ERF 8I18S45ERF 8P18S45ERF 8P18S45ERF 8P18S45ERF 8I18S42F 8I18S42F 8I18S42F 8P18S42F 8P18S42F 8P18S42F 8I1843F 8I1843F 8I1843F 8P1843F 8P1843F 8P1843F
8-MSOP -45 to 85C
8-MSOP -45 to 85C
8-MSOP -45 to 85C
8-MSOP -45 to 85C
8-MSOP -45 to 85C
8-MSOP -45 to 85C
Note: All Alliance Semiconductor Lead Free Parts are RoHS Compliant. All parts are Lead Free by default. Contact factory for Non Lead Free Parts. Licensed under US Patent numbers 5,488,627 and 5,631,921.
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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June 2005 rev 0.6
ASM8P18S42 / ASM8P18S42ER ASM8P1843 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER
Alliance Semiconductor Corporation 2575, Augustine Drive, Santa Clara, CA 95054 Tel# 408-855-4900 Fax: 408-855-4999 www.alsc.com
Copyright (c) Alliance Semiconductor All Rights Reserved Preliminary Information Part Number: ASM8P18S42 / ASM8P18S42ER ASM8P18S42 / ASM8P18S43ER ASM8P18S44ER / ASM8P18S45ER Document Version: v0.6
Note: This product utilizes US Patent # 6,646,463 Impedance Emulator Patent issued to Alliance Semiconductor, dated 11-11-2003
(c) Copyright 2003 Alliance Semiconductor Corporation. All rights reserved. Our three-point logo, our name and Intelliwatt are trademarks or registered trademarks of Alliance. All other brand and product names may be the trademarks of their respective companies. Alliance reserves the right to make changes to this document and its products at any time without notice. Alliance assumes no responsibility for any errors that may appear in this document. The data contained herein represents Alliance's best data and/or estimates at the time of issuance. Alliance reserves the right to change or correct this data at any time, without notice. If the product described herein is under development, significant changes to these specifications are possible. The information in this product data sheet is intended to be general descriptive information for potential customers and users, and is not intended to operate as, or provide, any guarantee or warrantee to any user or customer. Alliance does not assume any responsibility or liability arising out of the application or use of any product described herein, and disclaims any express or implied warranties related to the sale and/or use of Alliance products including liability or warranties related to fitness for a particular purpose, merchantability, or infringement of any intellectual property rights, except as express agreed to in Alliance's Terms and Conditions of Sale (which are available from Alliance). All sales of Alliance products are made exclusively according to Alliance's Terms and Conditions of Sale. The purchase of products from Alliance does not convey a license under any patent rights, copyrights; mask works rights, trademarks, or any other intellectual property rights of Alliance or third parties. Alliance does not authorize its products for use as critical components in life-supporting systems where a malfunction or failure may reasonably be expected to result in significant injury to the user, and the inclusion of Alliance products in such life-supporting systems implies that the manufacturer assumes all risk of such use and agrees to indemnify Alliance against all claims arising from such use.
Voltage Mode PWM Controller with EMI Reduction
Notice: The information in this document is subject to change without notice.
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