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August 2004 rev 2.0
Low Power Peak Reducing EMI Solution
Features
Generates an EMI optimized clocking signal at the output. Integrated loop filter components. Operates with a 3.3V 10% supply. Operating current less than 4mA. Low power CMOS design. Input frequency range: 15MHz to 30MHz. Generates a 1X low EMI spread spectrum clock of the input frequency. Frequency deviation: -1.25%. Available in 6-pin TSOT-23, 8-pin SOIC and 8-pin TSSOP packages.
ASM3P2879A
The ASM3P2879A uses the most efficient and optimized modulation profile approved by the FCC and is implemented by using a proprietary all digital method. The ASM3P2879A modulates the output of a single PLL in order to "spread" the bandwidth of a synthesized clock, and more importantly, decreases the peak amplitudes of its harmonics. This results in significantly lower system EMI compared to the typical narrow band signal produced by oscillators and most frequency generators. Lowering EMI by increasing a signal's bandwidth is called `spread spectrum clock generation'.
Applications
The ASM3P2879A is targeted towards all portable devices with very low power requirements like MP3 players, Notebooks and digital still cameras.
Product Description
The ASM3P2879A is a versatile spread spectrum frequency modulator designed specifically for a wide range of clock frequencies. The ASM3P2879A reduces electromagnetic interference (EMI) at the clock source, allowing system wide reduction of EMI of all clock dependent signals. The ASM3P2879A allows significant system cost savings by reducing the number of circuit board layers ferrite beads, shielding that are traditionally required to pass EMI regulations.
Key Specifications
Description Supply voltages Frequency Range Cycle-to-Cycle Jitter Output Duty Cycle Output Rise and Fall Time Modulation Rate Equation Frequency Deviation Specification VDD = 3.3V 10% 15MHz < CLKIN < 30MHz 300 ps (maximum) 40/60% (worst case) 5 ns (maximum) FIN/640 +1%
VDD
Block Diagram
Modulation XIN Crystal Oscillator XOUT Frequency Divider Feedback Divider
PLL
Phase Detector
Loop Filter
VCO
Output Divider ModOUT
REFOUT
VSS
Alliance Semiconductor 2575, Augustine Drive Santa Clara, CA Tel: 408.855.4900 Fax: 408.855.4999 www.alsc.com
Notice: The information in this document is subject to change without notice.
August 2004 rev 2.0
Pin Configuration (6-pin TSOT-23)
REFOUT 1 XOUT 2 XIN/CLKIN 3
6
ASM3P2879A
VSS ModOUT VDD
ASM3P2879A
5 4
Pin# 1 2 3 4 5 6
Pin Name REFOUT XOUT XIN/CLKIN VDD ModOUT VSS
Type O O I P O P
Description Buffered output of the input frequency. Crystal connection. If using an external reference, this pin must be left unconnected. Crystal connection or external reference frequency input. This pin has dual functions. It can be connected either to an external crystal or an external reference clock. Power supply for the entire chip (3.3V) Spread spectrum clock output. Ground connection.
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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Pin Configuration (8-pin SOIC and TSSOP)
XIN/CLKIN 1 XOUT 2
8 7
ASM3P2879A
VDD NC ModOUT VSS
ASM3P2879A
REFOUT 3 NC 4
6 5
Pin Description Pin# 1 2 3 4 5 6 7 8 Pin Name XIN/CLKIN XOUT REFOUT NC VSS ModOUT NC VDD Type I O O P O P Description Crystal connection or external reference frequency input. This pin has dual functions. It can be connected either to an external crystal or an external reference clock. Crystal connection. If using an external reference, this pin must be left unconnected. Buffered output of the input frequency. No connect. Ground connection. Spread spectrum clock output. No connect. Power supply for the entire chip (3.3V)
Modulation Profile
Specification Description Frequency Range Modulation Equation Frequency Deviation
Specification 15MHz < CLKIN < 30MHz FIN /640
+1%
Low Power Peak EMI Reducing Solution
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Absolute Maximum Ratings Symbol VDD , VIN TSTG Parameter
ASM3P2879A
Rating
Unit
Voltage on any pin with respect to Ground 0.5 to +7.0 V Storage temperature -65 to +125 C Operating temperature TA 0 to 70 C Note: These are stress ratings only and are not implied for functional use. Exposure to absolute maximum ratings for prolonged periods of time may affect device reliability.
DC Electrical Characteristics Symbol VIL VIH IIL IIH IXOL IXOH VOL VOH IDD ICC VDD tON ZOUT Input low voltage Input high voltage Input low current Input high current XOUT output low current (@4.0V, VDD =3.3V) XOUT output high current (@2.5V, VDD =3.3V) Output low voltage (VDD = 3.3 V, IOL = 20 mA) Output high voltage (VDD = 3.3 V, IOH = 20 mA) Static supply current Dynamic supply current (3.3V, 30MHz and 10pF loading) Operating voltage Power-up time (first locked cycle after power up) Clock output impedance Parameter Min GND - 0.3 2.0 - - - 2.5 - 2.7 - - Typ - - - - 3 3 - - 3.3 0.18 50 Max 0.8 VDD + 0.3 -35 35 0.4 - 10 4 3.7 - - Unit V V A A mA mA V V A mA V mS u
AC Electrical Characteristics Symbol CLKIN ModOUT REFOUT tLH * tHL * tJC Input frequency Output frequency Output rise time (measured at 0.8V to 2.0V) Output fall time (measured at 2.0V to 0.8V) Jitter (cycle to cycle) Parameter Min 15 15 15 0.7 0.6 45 Typ 0.9 0.8 50 Max 30 30 30 1.1 1.0 360 55 Unit MHz MHz ns ns ps %
tD Output duty cycle *tLH and tHL are measured into a capacitive load of 15pF
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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Package Information 6-pin TSOT-23
b
ASM3P2879A
B
C
A2
A
e
A1
D
H
L
Symbol
Dimensions in millimeters Min Max 1.00 0.10 0.87 REF 1.40 0.30 2.50 2.70 0.95 BSC 0.10 MIN 0.20 0 8 0.35 1.80 0.50 3.00 3.10
Dimensions in inches Min 0 Max 0.040 0.004 0.034 REF 0.055 0.012 0.098 0.106 0.071 0.019 0.118 0.122
A A1 A2 B b C D e H L
0
0.037 BSC 0.004 0.014
MIN 0.008 0 8
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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ASM3P2879A
8-Pin SOIC
E
H
D
A2
A
e B
A1
D
L
C
Symbol
Dimensions in inches Min Max 0.071 0.010 0.069 0.020 0.01 0.202 0.164
Dimensions in millimeters Min 1.45 0.10 1.35 0.31 0.10 4.72 3.75 Max 1.80 0.25 1.75 0.51 0.25 5.12 4.15 1.27 BSC 5.70 0.30 0 6.30 0.70 8
A A1 A2 B C D E e H L
0.057 0.004 0.053 0.012 0.004 0.186 0.148
0.050 BSC 0.224 0.012 0 0.248 0.028 8
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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8-Pin TSSOP
ASM3P2879A
H
E D A2 A e B A1 L C
Dimensions in inches Symbol A A1 A2 B C D E e H L Min 0.047 0.002 0.031 0.007 0.004 0.114 0.169 0.006 0.041 0.012 0.008 0.122 0.177 Max
Dimensions in millimeters Min Max 1.10 0.05 0.80 0.19 0.09 2.90 4.30 0.65 BSC 6.20 0.45 0 6.60 0.75 8 0.15 1.05 0.30 0.20 3.10 4.50
0.026 BSC 0.244 0.018 0 0.260 0.030 8
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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Ordering Information Part Number ASM3P2879AF-06OR ASM3P2879AF-08TT ASM3P2879AF-08TR ASM3P2879AF-08ST ASM3P2879AF-08SR Device Ordering Information Marking D1LL ASM3P2879A ASM3P2879A ASM3P2879A ASM3P2879A Package Type 6-Pin TSOT-23, TAPE & REEL 8-Pin TSSOP, TUBE 8-Pin TSSOP, TAPE & REEL 8-Pin SOIC, TUBE 8-Pin SOIC, TAPE & REEL
ASM3P2879A
Temperature 0C - 70oC 0oC - 70oC 0oC - 70oC 0oC - 70oC 0oC - 70oC
ASM3P2879AF-08TR
OR - SOT23/T/R TT - TSSOP, TUBE TR - TSSOP, T/R VT - TVSOP, TUBE VR - TVSOP, T/R ST - SOIC, TUBE SR - SOIC, T/R QR - QFN, T/R QT - QFN, TUBE BT - BGA, TUBE BR - BGA, T/R
PIN COUNT
LEAD FREE PART
PART NUMBER
X = Automotive
I = Industrial
P or n/c = Commercial
1 - reserved 2 - Non PLL based 3 - EMI Reduction 4 - DDR support products 5 - STD Zero Delay Buffer
6 - power management 7 - power management 8 - power management 9 - Hi performance 0 - reserved
Alliance Semiconductor Mixed Signal Product
Licensed under U.S Patent Nos 5,488,627 and 5,631,921
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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ASM3P2879A
Alliance Semiconductor Corporation 2575, Augustine Drive, Santa Clara, CA 95054 Tel# 408-855-4900 Fax: 408-855-4999 www.alsc.com
Copyright y Alliance Semiconductor All Rights Reserved Preliminary Information Part Number: ASM3P2879A Document Version: v 2.0 8_30_2004
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.
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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