September 2005 ASM3P2759A
rev 1.6
Notice: The information in this document is subject to change without notice.
Alliance Semiconductor
2575 Augustine Drive • Santa Clara, CA • Tel: 408.855.4900 • Fax: 408.855.4999 • www.alsc.com
Low Power Peak EMI Reducing Solution
Features
Generates an EMI optimized clock signal at the
output.
Integrated loop filter components.
Operates with a 3.3V / 2.5V Supply.
Operating current less than 4mA.
Low power CMOS design.
Input frequency range: 3MHz to 5MHz for 2.5V
: 3MHz to 6MHz for 3.3V
Generates a 1X low EMI spread spectrum clock of
the input frequency.
Frequency deviation: ±1% @ 3MHz
Available in 6-pin TSOT-23, 8-pin SOIC and 8-pin
TSSOP packages.
Product Description
The ASM3P2759A is a versatile spread spectrum
frequency modulator designed specifically for a wide
range of clock frequencies. The ASM3P2759A reduces
electromagnetic interference (EMI) at the clock source,
allowing system wide reduction of EMI of all clock
dependent signals. The ASM3P2759A allows significant
system cost savings by reducing the number of circuit
board layers ferrite beads, shielding that are traditionally
required to pass EMI regulations.
The ASM3P2759A uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented by using a proprietary all digital method.
The ASM3P2759A 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 ASM3P2759A is targeted towards all portable devices
with very low power requirements like MP3 players and
digital still cameras.
Key Specifications
Description Specification
Supply voltages VDD = 3.3V / 2.5V
Cycle-to-Cycle Jitter 200pS (Max)
Output Duty Cycle 45/55%
Modulation Rate Equation FIN/128
Frequency Deviation ±1% @ 3MHz
Block Diagram
ModOUT
VDD
XIN
VSS
Frequency
Divide
r
Feedback
Divide
r
Modulation
Phase
Detecto
r
Loop
Filte
r
VCO Output
Divide
r
PLL
PD
Crystal
Oscillator
XOUT
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 2 of 12
Notice: The information in this document is subject to change without notice.
Pin Configuration (6-pin TSOT- 23 Package)
Pin Description
Pin# Pin Name Type Description
1
PD I Power-down control pin. Pull low to enable power-down mode. Connect to VDD if not
used.
2 XOUT O Crystal connection. If using an external reference, this pin must be left unconnected.
3 XIN/CLKIN I 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.
4 VDD P Power supply for the entire chip
5 ModOUT O Spread spectrum clock output.
6 VSS P Ground connection.
XOUT
1
2
3 4
5
6
ASM3P2759A
PD
XIN/CLKIN VDD
ModOUT
VSS
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 3 of 12
Notice: The information in this document is subject to change without notice.
Pin Configuration (8-pin SOIC and TSSOP Packages)
Pin Description
Pin# Pin Name Type Description
1 XIN/CLKIN I 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.
2 XOUT O Crystal connection. If using an external reference, this pin must be left unconnected.
3
PD I Power-down control pin. Pull low to enable power-down mode. Connect to VDD if not
used.
4 NC - No connect.
5 VSS P Ground connection.
6 ModOUT O Spread spectrum clock output.
7 NC - No connect.
8 VDD P Power supply for the entire chip
Modulation Profile
Specification
Description Specification
For 2.5V Supply 3MHz < CLKIN < 5MHz
Frequency Range For 3.3V Supply 3MHz < CLKIN < 6MHz
Modulation Equation FIN/128
Frequency Deviation ±1% @ 3MHz
XIN/CLKIN
VSS
ModOUT
NC
XOUT
1
2
3
4 5
6
7
8
ASM3P2759A
PD
NC
VDD
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 4 of 12
Notice: The information in this document is subject to change without notice.
Absolute Maximum Ratings
Symbol Parameter Rating Unit
VDD, VIN Voltage on any pin with respect to Ground -0.5 to +7.0 V
TSTG Storage temperature -65 to +125 °C
TA Operating temperature 0 to 70 °C
Ts Max. Soldering Temperature (10 sec) 260 °C
TJ Junction Temperature 150 °C
TDV Static Discharge Voltage
(As per JEDEC STD22- A114-B)
2 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.
DC Electrical Characteristics for 2.5V Supply
(Test condition: All parameters are measured at room temperature (+25°C) unless otherwise stated)
Symbol Parameter Min Typ Max Unit
VIL Input low voltage VSS - 0.3 - 0.8 V
VIH Input high voltage 2.0 - VDD + 0.3 V
IIL Input low current - - -35 µA
IIH Input high current - - 35 µA
IXOL XOUT output low current (@0.5V, VDD=2.5V) - 3 - mA
IXOH XOUT output high current (@1.8V, VDD=2.5V) - 3 - mA
VOL Output low voltage (VDD = 2.5 V, IOL = 8mA) - - 0.6 V
VOH Output high voltage (VDD = 2.5 V, IOH = 8mA) 1.8 - - V
IDD Static supply current* - - 10 uA
ICC Dynamic supply current (2.5V, 3MHz and with no load) - 2.0 - mA
VDD Operating Voltage 2.375 2.5 2.625 V
tON Power-up time (first locked cycle after power-up)** - - 5 mS
ZOUT Output impedance - 50 - Ω
* XIN/CLKIN and PD pin are pulled low
** VDD and XIN/CLKIN input are stable, PD pin is made high from low.
AC Electrical Characteristics for 2.5V Supply
Symbol Parameter Min Typ Max Unit
CLKIN Input frequency 3 - 5 MHz
ModOUT Output frequency 3 - 5 MHz
Input Frequency = 3MHz - ±1 -
fd Frequency Deviation
Input Frequency = 5MHz - ±0.6 - %
tLH* Output rise time (measured from 0.7V to 1.7V) 0.5 1.0 1.2 nS
tHL* Output fall time (measured from 1.7V to 0.7V) 0.4 0.9 1.1 nS
tJC Jitter (cycle to cycle) - - 200 pS
tD Output duty cycle 45 50 55 %
* tLH and tHL are measured into a capacitive load of 15pF
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 5 of 12
Notice: The information in this document is subject to change without notice.
DC Electrical Characteristics for 3.3V Supply
(Test condition: All parameters are measured at room temperature (+ 25°C) unless otherwise stated)
Symbol Parameter Min Typ Max Unit
VIL Input low voltage VSS - 0.3 - 0.8 V
VIH Input high voltage 2.0 - VDD + 0.3 V
IIL Input low current - - -35 µA
IIH Input high current - - 35 µA
IXOL XOUT output low current (@0.4V, VDD=3.3V) - 3 - mA
IXOH XOUT output high current (@2.5V, VDD=3.3V) - 3 - mA
VOL Output low voltage (VDD = 3.3 V, IOL = 8mA) - - 0.4 V
VOH Output high voltage (VDD = 3.3 V, IOH = 8mA) 2.5 - - V
IDD Static supply current* - 10 uA
ICC Dynamic supply current (3.3V, 3MHz and with no load) - 2.5 - mA
VDD Operating Voltage 2.7 3.3 3.6 V
tON Power-up time (first locked cycle after power-up)** - - 5 mS
ZOUT Output impedance - 45 - Ω
* XIN/CLKIN and PD pin are pulled low
** VDD and XIN/CLKIN input are stable; PD pin is made high from low.
AC Electrical Characteristics for 3.3V Supply
Symbol Parameter Min Typ Max Unit
CLKIN Input frequency 3 - 6 MHz
ModOUT Output frequency 3 - 6 MHz
Input Frequency = 3MHz - ±1 -
fd Frequency
Deviation Input Frequency = 6MHz - ±0.55 -
%
tLH* Output rise time (measured from 0.8 to 2.0V) 0.4 1.0 1.2 nS
tHL * Output fall time (measured at 2.0V to 0.8V) 0.4 0.9 1.0 nS
tJC Jitter (cycle to cycle) - - 200 pS
tD Output duty cycle 45 50 55 %
*tLH and tHL are measured into a capacitive load of 15pF
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 6 of 12
Notice: The information in this document is subject to change without notice.
Typical Crystal Oscillator Circuit
Typical Crystal Specifications
Fundamental AT cut parallel resonant crystal
Nominal frequency 4.800MHz
Frequency tolerance ± 50 ppm or better at 25°C
Operating temperature range -25°C to +85°C
Storage temperature -40°C to +85°C
Load capacitance 18pF
Shunt capacitance 7pF maximum
ESR 25 Ω
R1 = 510Ω
C1 = 27 pF C2 = 27 pF
Crystal
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 7 of 12
Notice: The information in this document is subject to change without notice.
Package Information
6-pin TSOT-23 Package
Dimensions
Inches Millimeters
Symbol
Min Max Min Max
A 0.04 1.00
A1 0.00 0.004 0.00 0.10
A2 0.033 0.036 0.84 0.90
b 0.012 0.02 0.30 0.50
H 0.005 BSC 0.127 BSC
D 0.114 BSC 2.90 BSC
B 0.06 BSC 1.60 BSC
e 0.0374 BSC 0.950 BSC
C 0.11 BSC 2.80 BSC
L 0.0118 0.02 0.30 0.50
θ 0° 4° 0° 4°
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 8 of 12
Notice: The information in this document is subject to change without notice.
8-Pin SOIC Package
D
EH
D
A1
A2
A
θ
L
C
B
e
Dimensions
Inches Millimeters
Symbol
Min Max Min Max
A1 0.004 0.010 0.10 0.25
A 0.053 0.069 1.35 1.75
A2 0.049 0.059 1.25 1.50
B 0.012 0.020 0.31 0.51
C 0.007 0.010 0.18 0.25
D 0.193 BSC 4.90 BSC
E 0.154 BSC 3.91 BSC
e 0.050 BSC 1.27 BSC
H 0.236 BSC 6.00 BSC
L 0.016 0.050 0.41 1.27
θ 0° 8° 0° 8°
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 9 of 12
Notice: The information in this document is subject to change without notice.
E
H
A
A1
A2
D
B
C
L
θ
e
8-Pin TSSOP Package
Dimensions
Inches Millimeters
Symbol
Min Max Min Max
A 0.043 1.10
A1 0.002 0.006 0.05 0.15
A2 0.033 0.037 0.85 0.95
B 0.008 0.012 0.19 0.30
c 0.004 0.008 0.09 0.20
D 0.114 0.122 2.90 3.10
E 0.169 0.177 4.30 4.50
e 0.026 BSC 0.65 BSC
H 0.252 BSC 6.40 BSC
L 0.020 0.028 0.50 0.70
θ 0° 8° 0° 8°
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 10 of 12
Notice: The information in this document is subject to change without notice.
Ordering Information
Part Number Marking Package Type Temperature
ASM3P2759AF-06OR O4LL 6-Pin TSOT-23, TAPE & REEL, Pb Free Commercial
ASM3P2759AF-08TT 3P2759AF 8-Pin TSSOP, TUBE, Pb Free Commercial
ASM3P2759AF-08TR 3P2759AF 8-Pin TSSOP, TAPE & REEL, Pb Free Commercial
ASM3P2759AF-08ST 3P2759AF 8-Pin SOIC, TUBE, Pb Free Commercial
ASM3P2759AF-08SR 3P2759AF 8-Pin SOIC, TAPE & REEL, Pb Free Commercial
ASM3P2759AG-06OR O3LL 6-Pin TSOT-23, TAPE & REEL, Green Commercial
ASM3P2759AG-08TT 3P2759AG 8-Pin TSSOP, TUBE, Green Commercial
ASM3P2759AG-08TR 3P2759AG 8-Pin TSSOP, TAPE & REEL, Green Commercial
ASM3P2759AG-08ST 3P2759AG 8-Pin SOIC, TUBE, Green Commercial
ASM3P2759AG-08SR 3P2759AG 8-Pin SOIC, TAPE & REEL, Green Commercial
ASM3P2759A-06OR O1LL 6-Pin TSOT-23, TAPE & REEL Commercial
ASM3P2759A-08TT 3P2759A 8-Pin TSSOP, TUBE Commercial
ASM3P2759A-08TR 3P2759A 8-Pin TSSOP, TAPE & REEL Commercial
ASM3P2759A-08ST 3P2759A 8-Pin SOIC, TUBE Commercial
ASM3P2759A-08SR 3P2759A 8-Pin SOIC, TAPE & REEL Commercial
ASM3I2759AF-06OR O5LL 6-Pin TSOT-23, TAPE & REEL, Pb Free Industrial
ASM3I2759AF-08TT 3I2759AF 8-Pin TSSOP, TUBE, Pb Free Industrial
ASM3I2759AF-08TR 3I2759AF 8-Pin TSSOP, TAPE & REEL, Pb Free Industrial
ASM3I2759AF-08ST 3I2759AF 8-Pin SOIC, TUBE, Pb Free Industrial
ASM3I2759AF-08SR 3I2759AF 8-Pin SOIC, TAPE & REEL, Pb Free Industrial
ASM3I2759AG-06OR O6LL 6-Pin TSOT-23, TAPE & REEL, Green Industrial
ASM3I2759AG-08TT 3I2759AG 8-Pin TSSOP, TUBE, Green Industrial
ASM3I2759AG-08TR 3I2759AG 8-Pin TSSOP, TAPE & REEL, Green Industrial
ASM3I2759AG-08ST 3I2759AG 8-Pin SOIC, TUBE, Green Industrial
ASM3I2759AG-08SR 3I2759AG 8-Pin SOIC, TAPE & REEL, Green Industrial
ASM3I2759A-06OR O2LL 6-Pin TSOT-23, TAPE & REEL Industrial
ASM3I2759A-08TT 3I2759A 8-Pin TSSOP, TUBE Industrial
ASM3I2759A-08TR 3I2759A 8-Pin TSSOP, TAPE & REEL Industrial
ASM3I2759A-08ST 3I2759A 8-Pin SOIC, TUBE Industrial
ASM3I2759A-08SR 3I2759A 8-Pin SOIC, TAPE & REEL Industrial
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 11 of 12
Notice: The information in this document is subject to change without notice.
Device Ordering Information
ASM3P2759AF-08TR
Licensed under U.S Patent Nos 5,488,627 and 5,631,921
O = SOT U = MSOP
S = SOIC E = TQFP
T = TSSOP L = LQFP
A = SSOP U = MSOP
V = TVSOP P = PDIP
B = BGA D = QSOP
Q
=
QFN
=
-
70
DEVICE PIN COUNT
X= Automotive I= Industrial P or n/c = Commercial
(-40C to +125C) (-40C to +85C) (0C to +70C)
1 = Reserved 6 = Power Management
2 = Non PLL based 7 = Power Management
3 = EMI Reduction 8 = Power Management
4 = DDR support products 9 = Hi Performance
5 = STD Zero Dela
y
Buffe
r
0 = Reserved
ALLIANCE SEMICONDUCTOR MIXED SIGNAL PRODUCT
PART NUMBER
F = LEAD FREE AND RoHS COMPLIANT PART
G = GREEN PACKAGE
R = Tape & reel, T = Tube or Tray
September 2005 ASM3P2759A
rev 1.6
Low Power Peak EMI Reducing Solution 12 of 12
Notice: The information in this document is subject to change without notice.
Note: This product utilizes US Patent # 6,646,463 Impedance Emulator Patent issued to Alliance Semiconductor, dated 11-11-2003
© 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.
Alliance Semiconductor Corporation
2575 Augustine Drive,
Santa Clara, CA 95054
Tel# 408-855-4900
Fax: 408-855-4999
www.alsc.com
Copyright © Alliance Semiconductor
All Rights Reserved
Preliminary Information
Part Number: ASM3P2759A
Document Version: v1.6