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November 2006 rev 1.3 Peak EMI Reducing Solution
Features
* * * Generates an EMI optimized clock signal at output. Input frequency: 25MHz. Frequency outputs: * USB Clock (48MHz unmodulated) * 50MHz (modulated), 1% centre spread * * * * * Modulation rate: 39KHz. Spread Spectrum ON/OFF control Supply voltage range 2.5V 5%. Available in 8 Pin SOIC package. Commercial and Industrial Temperature range.
ASM3P2853A
shielding that are required to pass EMI regulations. The ASM3P2853A modulates the output of PLL in order to spread the bandwidth of a synthesized clock, thereby decreasing 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 clock generators. Lowering EMI by increasing a signal's bandwidth is called spread spectrum clock generation.
Applications
ASM3P2853A is targeted towards EMI management for high speed digital applications such as PC peripheral devices, consumer electronics and embedded controller systems.
Product Description
The ASM3P2853A is a versatile spread spectrum frequency modulator. The ASM3P2853A reduces electromagnetic interference (EMI) at the clock source. The ASM3P2853A allows significant system cost savings by reducing the number of circuit board layers and
Block Diagram
VDD PWDNB
XIN XOUT
Crystal Oscillator
PLL1
USB Clock (48MHz Unmodulated)
SSONB
PLL2
50MHz Modulated
VSS
PulseCore Semiconductor Corporation 1715 S. Bascom Ave Suite 200, Campbell, CA 95008 * Tel: 408-879-9077 * Fax: 408-879-9018 www.pulsecoresemi.com
Notice: The information in this document is subject to change without notice.
November 2006 rev 1.3
Pin Configuration
ASM3P2853A
XIN XOUT VDD VSS
1 2 3 4
8 7
50MHz USB Clock SSONB PWDNB
ASM3P2853A
6 5
Pin Description Pin# Pin Name
XIN
Type
Description
Connection to crystal or external reference frequency input. This pin has dual
1
I
functions. It can be connected either to an external crystal or an external reference clock. Connection to crystal. If using an external reference clock, this pin must be left unconnected. Power supply for the analog and digital blocks Ground to entire chip. Power-down control pin. Pull low to enable the power-down mode. Connect to VDD, if not used. Digital logic input used to enable spread spectrum function (Active LOW). Spread spectrum is enabled when LOW, disabled when HIGH. Clock output -1 (48MHz unmodulated) Clock output -2 (50MHz modulated)
2 3 4 5 6 7 8
XOUT VDD VSS PWDNB SSONB USB Clock 50MHz
O P P I I O O
Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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November 2006 rev 1.3
Absolute Maximum Ratings Symbol
VDD, VIN TSTG TA Ts TJ TDV Storage temperature Operating temperature Max. Soldering Temperature (10 sec) Junction Temperature Static Discharge Voltage (As per JEDEC STD22- A114-B)
ASM3P2853A
Parameter
Voltage on any pin with respect to Ground
Rating
-0.5 to +4.6 -65 to +125 -40 to +85 260 150 2
Unit
V C C C C KV
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.
Operating Conditions Parameter
Supply Voltage Ambient Operating Temperature Range Crystal Resonator Frequency Output Driver Load Capacitance
Symbol
VDD TA FXIN CL
Condition / Description
2.5V 5%
Min
2.375 -40
Typ
2.5 25
Max
2.625 +85
Unit
V C MHz
-
-
15
pF
Crystal Specifications Fundamental AT cut parallel resonant crystal
Nominal frequency Frequency tolerance Operating temperature range Storage temperature Load capacitance Shunt capacitance ESR 25MHz 50ppm or better at 25C -25C to +85C -40C to +85C 18pF 7pF maximum 25
Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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November 2006 rev 1.3
DC Electrical Characteristics Parameter Overall
Supply Current, Dynamic Supply Current, Static IDD IDDL VDD=2.5V, FXIN=25MHz, CL=15pF VDD = 2.5V, XIN = 0, PWDNB =0 7 13 12
ASM3P2853A
Symbol
Conditions / Description
Min
Typ
Max
Unit
20 -
mA uA
All input pins
High-Level Input Voltage Low-Level Input Voltage High-Level Input Current Low-Level Input Current (pull-up) VIH VIL IIH IIL VDD=2.5V VDD=2.5V 1.7 0.7 25 -25 V V
A
A
Clock Outputs
High-Level Output Source Current Low-Level Output Sink Current High-Level Output Source Current Low-Level Output Sink Current IxOH IxOL IOH IOL VDD= 2.5V ,V(XIN) = 0, VO=2V VDD= V(XIN) =2.5V, VO=0.4V VO=2V VO=0.4V -15 15 8 mA mA mA
-
8
-
mA
Output Impedance
ZO
-
42
-
Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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November 2006 rev 1.3
AC Electrical Characteristics Parameter
Rise Time*
ASM3P2853A
Symbol
tr
Conditions/ Description
Measured from 20% to 80% of the signal level Measured from 80% to 20% of the
Min
-
Typ
2
Max
-
Unit
nS
Fall Time* Jitter (Cycle to Cycle) Jitter (Period) Clock Duty Cycle
tf
signal level
-
1.5
-
nS
tjc tp Ratio of pulse width (as measured from td rising edge to next falling edge at VDD/2) to one clock period
-
250 175
-
pS pS
45
50
55
%
* CL = 15 pF, Input clock frequency = 25MHz
Typical Application Schematic using ASM3P2853A Device
25MHz fundamental Crystal
1
XIN XOUT VDD
50MHz USB Clock SSONB
8 7 6 5
Modulated 50MHz output Un-modulated 48MHz output
27pF
2
27pF
3 4
+2.5V
0.1uF
VSS PWDNB ASM3P2853A
Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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November 2006 rev 1.3
Package Information
ASM3P2853A
8-Pin SOIC package
E
H
D
A2
A
e B A 1
C L
D
Dimensions
Symbol Min
A1 A A2 B C D E e H L
Inches Max
0.010 0.069 0.059 0.020 0.010 0.004 0.053 0.049 0.012 0.007
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
Coplanarity < = 4 mil
Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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November 2006 rev 1.3
Ordering Codes Part number
ASM3P2853AF-08ST ASM3P2853AF-08SR ASM3P2853AG-08ST ASM3P2853AG-08SR ASM3I2853AF-08ST ASM3I2853AF-08SR ASM3I2853AG-08ST ASM3I2853AG-08SR
ASM3P2853A
Marking
3P2853AF 3P2853AF 3P2853AG 3P2853AG 3I2853AF 3I2853AF 3I2853AG 3I2853AG
Package Configuration
8-pin SOIC ,TUBE, Pb Free 8-pin SOIC, TAPE & REEL, Pb Free 8-pin SOIC ,TUBE, Green 8-pin SOIC, TAPE & REEL, Green 8-pin SOIC ,TUBE, Pb Free 8-pin SOIC, TAPE & REEL, Pb Free 8-pin SOIC ,TUBE, Green 8-pin SOIC, TAPE & REEL, Green
Temperature Range
Commercial Commercial Commercial Commercial Industrial Industrial Industrial Industrial
Device Ordering Information
ASM3P2853AF-08SR
R = Tape & Reel, T = Tube or Tray O = SOT S = SOIC T = TSSOP A = SSOP V = TVSOP B = BGA Q = QFN DEVICE PIN COUNT F = LEAD FREE AND RoHS COMPLIANT PART G = GREEN PACKAGE, LEAD FREE, and RoHS PART NUMBER X= Automotive I= Industrial P or n/c = Commercial (-40C to +125C) (-40C to +85C) (0C to +70C) 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 U = MSOP E = TQFP L = LQFP U = MSOP P = PDIP D = QSOP X = SC-70
PulseCore Semiconductor Mixed Signal Product
Licensed under US patent #5,488,627, #6,646,463 and #5,631,920.
Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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November 2006 rev 1.3
ASM3P2853A
PulseCore Semiconductor Corporation 1715 S. Bascom Ave Suite 200 Campbell, CA 95008 Tel: 408-879-9077 Fax: 408-879-9018 www.pulsecoresemi.com
Copyright (c) PulseCore Semiconductor All Rights Reserved Preliminary Information Part Number: ASM3P2853A Document Version: v1.3
Note: This product utilizes US Patent # 6,646,463 Impedance Emulator Patent issued to PulseCore Semiconductor, dated 11-11-2003
(c) Copyright 2006 PulseCore Semiconductor Corporation. All rights reserved. Our logo and name are trademarks or registered trademarks of PulseCore Semiconductor. All other brand and product names may be the trademarks of their respective companies. PulseCore reserves the right to make changes to this document and its products at any time without notice. PulseCore assumes no responsibility for any errors that may appear in this document. The data contained herein represents PulseCore's best data and/or estimates at the time of issuance. PulseCore 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. PulseCore 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 PulseCore 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 PulseCore's Terms and Conditions of Sale (which are available from PulseCore). All sales of PulseCore products are made exclusively according to PulseCore's Terms and Conditions of Sale. The purchase of products from PulseCore does not convey a license under any patent rights, copyrights; mask works rights, trademarks, or any other intellectual property rights of PulseCore or third parties. PulseCore 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 PulseCore products in such life-supporting systems implies that the manufacturer assumes all risk of such use and agrees to indemnify PulseCore against all claims arising from such use.
Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
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