ASM3P2812B-08TT [ALSC]
Clock Generator;
| 型号： | ASM3P2812B-08TT |
| 厂家： | 
ALLIANCE SEMICONDUCTOR CORPORATION |
| 描述： | Clock Generator |
| 文件： | 总8页 (文件大小：160K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
September 2003
rev 1.0
ASM3P2811A/B
ASM3P2812A/B
ASM3P2814A/B
Low Power EMI Reduction IC
Features
deviation range from ±0.625% to –3.50%.
ꢀ
ꢀ
ꢀ
FCC approved method of EMI attenuation.
Provides up to 15dB EMI reduction.
The ASM3P28XX reduces electromagnetic interference
(EMI) at the clock source, allowing system wide reduction
of EMI of down stream clock and data dependent
signals. The ASM3P28XX allows significant system cost
savings by reducing the number of circuit board layers,
ferrite beads, shielding, and other passive components
that are traditionally required to pass EMI regulations.
Generates a 1X, 2X and 4X low EMI spread
spectrum clock of the input frequency.
o
o
o
1X: ASM3P2811A/B
2X: ASM3P2812A/B
4X: ASM3P2814A/B
ꢀ
Optimized for input frequency range from 10MHz
to 40 MHz.
o
o
o
ASM3P2811A/B: 10 to 40MHz
ASM3P2812A/B: 10 to 40MHz
ASM3P2814A/B: 10 to 40MHz
The ASM3P28XX 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’.
ꢀ
ꢀ
ꢀ
Internal loop filter minimizes external components
and board space.
Selectable spread options: Down Spread and
Center Spread.
8 spread frequency deviation selections:
o
±0.625% to –3.5%
ꢀ
ꢀ
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Low inherent cycle-to-cycle jitter.
3.3V operating voltage range.
The ASM3P28XX uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented in a proprietary all-digital method.
CMOS/TTL compatible inputs and outputs.
Pinout compatible with Cypress CY25811,
CY25812 and CY25814.
ꢀ
Products are available for industrial temperature
range.
Applications
The ASM3P28XX is targeted towards EMI management
for memory and LVDS interfaces in mobile graphic
chipsets and high-speed digital applications such as PC
peripheral devices, consumer electronics, and embedded
controller systems.
ꢀ
Available in 8-pin SOIC and TSSOP.
Product Description
The ASM3P28XX devices are versatile spread spectrum
frequency modulators designed specifically for a wide
range of input clock frequencies from 10MHz to 40MHz.
(Refer Input/Output Frequency Range Selection Table).
The ASM3P28XX can generate an EMI reduced clock
from crystal, ceramic resonator, or system clock. The
ASM3P28XX-A and the ASM3P28XX-B offer various
combinations of spread options and percentage
deviations (Refer Output Frequency Deviation and
Spread Option Selection Table). These combinations
include Down and Center Spread and percentage
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.
September 2003
ASM3P2811A/B
ASM3P2812A/B
ASM3P2814A/B
rev 1.0
Block Diagram
VDD
D_C SRS FRS
Modulation
PLL
XIN
Crystal
Oscillator
Frequency
Divider
Output
Divider
Phase
Detector
Loop
Filter
VCO
XOUT
Feedback
Divider
ModOUT
VSS
Pin Configuration
1
8
7
6
5
XOUT
XIN
VSS
D_C
2
3
4
VDD
ASM3P2811A/B
ASM3P2812A/B
ASM3P2814A/B
FRS
ModOUT
SRS
Low Power EMI Reduction IC
2 of 6
Notice: The information in this document is subject to change without notice.
September 2003
ASM3P2811A/B
ASM3P2812A/B
ASM3P2814A/B
rev 1.0
Pin Description
Pin#
Pin Name
XIN
Type
Description
Crystal connection or external frequency input. This pin has dual functions.
It can be connected to either an external crystal or an external reference
clock.
1
2
3
I
P
I
VSS
Ground to entire chip.
Digital logic input used to select Down (LOW) or Center (HIGH) spread
options. (Refer Output Frequency Deviation and Spread Option Selection
Table). This pin has an internal pull-up resistor.
D_C
Spread range select. Digital logic input used to select frequency deviation
(Refer Output Frequency Deviation and Spread Option Selection Table).
This pin has an internal pull-up resistor.
Spread spectrum clock output (Refer Input/Output Frequency Range
Selection Table and Output Frequency Deviation and Spread Option
Selection Table).
Frequency range select. Digital logic input used to select input frequency
range (Refer Input/Output Frequency Deviation and Spread Option
Selection Table). This pin has an internal pull-up resistor.
4
5
6
SRS
ModOUT
FRS
I
O
I
7
8
VDD
P
I
Power supply for the entire chip (3.3V).
Crystal connection. Input connection for an external crystal. If using an
external reference, this pin must be left unconnected.
XOUT
Input/Output Frequency Range Selection Table
Part Number
ASM3P2812 (2X)
FRS (pin 6)
Modulation Rate
ASM3P2811 (1X)
ASM3P2814 (4X)
Input
(MHz)
Output
(MHz)
Input
(MHz)
Output
(MHz)
Input
(MHz)
Output
(MHz)
0
1
10-20
20-40
10-20
20-40
10-20
20-40
20-40
40-80
10-20
20-40
40-80
Input Frequency / 448
Input Frequency / 896
80-160
Low Power EMI Reduction IC
3 of 6
Notice: The information in this document is subject to change without notice.
September 2003
ASM3P2811A/B
ASM3P2812A/B
ASM3P2814A/B
rev 1.0
Output Frequency Deviation and Spread Option Selection Table
Output frequency deviation
Part Number
D_C (pin 3)
SRS (pin 4)
and spread option
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
-2.50% (Down)
-3.50% (Down)
± 1.25% (Center)
±1.75% (Center)
-1.25% (Down)
ASM3P28XXA
-1.75% (Down)
ASM3P28XXB
± 0.625% (Center)
± 0.875% (Center)
Absolute Maximum Ratings
Symbol
Parameter
Rating
Unit
V
VDD, VIN
TSTG
Voltage on any pin with respect to GND
Storage temperature
-0.5 to + 7.0
-65 to +125
0 to 70
°C
°C
TA
Operating temperature
Note: These are stress ratings only and functional operation is not implied. Exposure to absolute maximum
ratings for extended periods may affect device reliability.
Low Power EMI Reduction IC
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Notice: The information in this document is subject to change without notice.
September 2003
ASM3P2811A/B
ASM3P2812A/B
ASM3P2814A/B
rev 1.0
DC Electrical Characteristics (3.3V, 25°C)
Symbol
Parameter
Min
Typ
Max
Unit
VIL
VIH
Input low voltage
GND – 0.3
-
-
-
0.8
V
V
Input high voltage
Input low current
(inputs D_C, SRS and FRS)
VDD + 0.3
IIL
-60.00
-
-
-
-
-20.00
1.00
µA
µA
IIH
Input high current
XOUT Output low current
(@ 0.4V, VDD = 3.3V)
IXOL
2.00
12.00
mA
XOUT Output high current
(@ 2.5V, VDD = 3.3V)
IXOH
-
-
12.00
mA
VOL
VOH
Output low voltage (VDD = 3.3V, IOL = 20mA)
Output high voltage (VDD = 3.3V, IOH = 20mA)
-
-
-
0.4
-
V
V
2.8
Dynamic supply current
Normal mode (3.3V and 25pF loading)
Static supply current
ICC
7.1 fIN - min
-
13.9 fIN - max
mA
IDD
-
-
-
-
4.5
3.3
-
-
-
-
mA
V
Standby mode
VDD
tON
Operating voltage
Power up time (first locked clock cycle after power
up)
0.18
50
mS
Ω
ZOUT
Clock out impedance
AC Electrical Characteristics
Symbol
Parameter
Min
Typ Max Unit
fIN
Input frequency ASM3P2811/12/13/14 A/B
Output frequency for ASM3P211A/B
Output frequency for AS3P2812A/B
Output frequency for AS3P2814A/B
Output rise time (measured at 0.8V to 2.0V)
Output fall time (measured at 2.0V to 0.8V)
Jitter (cycle to cycle)
10
10
20
40
-
-
40
40
80
MHz
MHz
MHz
-
fOUT
-
-
160 MHz
tLH*
tHL*
tJC
0.69
0.66
-
-
-
ns
ns
ps
%
-
-200
45
200
55
TD
Output duty cycle
50
* tLH and tHL are measured into a capacitive load of 15pF
Low Power EMI Reduction IC
5 of 6
Notice: The information in this document is subject to change without notice.
September 2003
ASM3P2811A/B
ASM3P2812A/B
ASM3P2814A/B
rev 1.0
Package Information
8-Pin SOIC
H
E
D
A2
A
C
θ
e
A1
D
L
B
Symbol Dimensions in inches Dimensions in millimeters
Min
Max
0.071
0.010
0.069
0.020
0.01
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
A
A1
A2
B
0.057
0.004
0.053
0.012
0.004
0.186
0.148
C
D
E
0.202
0.164
E
0.050 BSC
1.27 BSC
H
L
0.224
0.012
0°
0.248
0.028
8°
5.70
0.30
0°
6.30
0.70
8°
θ
Note: Controlling dimensions are millimeters.
SOIC: 0.074 grams unit weight.
Low Power EMI Reduction IC
6 of 6
Notice: The information in this document is subject to change without notice.
September 2003
rev 1.0
ASM3P2811A/B
ASM3P2812A/B
ASM3P2814A/B
8-Pin TSSOP
H
E
D
A2
A
C
θ
e
A1
L
B
Dimensions in inches
Dimensions in millimeters
Symbol
Min
Max
Min
Max
1.10
0.15
1.05
0.30
0.20
3.10
4.50
A
A1
A2
B
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
0.05
0.80
0.19
0.09
2.90
4.30
C
D
E
E
0.026 BSC
0.65 BSC
H
L
0.244
0.018
0°
0.260
0.030
8°
6.20
0.45
0°
6.60
0.75
8°
θ
Note: Controlling dimensions are millimeters.
TSSOP: 0.034 grams unit weight.
Low Power EMI Reduction IC
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Notice: The information in this document is subject to change without notice.
September 2003
rev 1.0
ASM3P2811A/B
ASM3P2812A/B
ASM3P2814A/B
Copyright © Alliance Semiconductor
All Rights Reserved
Preliminary Information
Part Numbers: ASM3P2811A/B
ASM3P2812A/B
Alliance Semiconductor Corporation
2595, Augustine Drive,
Santa Clara, CA 95054
Tel# 408-855-4900
Fax: 408-855-4999
www.alsc.com
ASM3P2814A/B
Document Version: v1.0
© 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
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assumes all risk of such use and agrees to indemnify Alliance against all claims arising from such use.
Low Power EMI Reduction IC
8 of 8
Notice: The information in this document is subject to change without notice.
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