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ASM3P2779AF-06OR

P1-P3P4-P6P7-P7
ASM3P2779A
Peak EMI
Reducing Solution
©2010 SCILLC. All rights reserved. Publi
cation Order Number:
OCTOBER 2010 – Rev. 4.1 ASM3P2779/D
Features
• Generates an EMI optimized clock signal at the
outp
ut.
• Integrated loop filter components.
• Operates with a 3.3 / 2.5V Supply.
• Operating current less than 4mA.
• CMOS design.
• Input frequency range: 13MHz to 30MHz for 2.5V
13MHz to 30MHz for 3.3V
• Generates a 1X low EMI spread spectrum clock of
the input frequency.
• Frequency deviation: ±1% (Typ) @ 16MHz Input
Frequency.
• Available in 6L-TSOP (6L-TSOT-23).
Product Description
The ASM3P2779A is a versatile spread spectrum
frequency modulator designed specifically for a wide
range of clock frequencies. The ASM3P2779A reduces
electromagnetic interference (EMI) at the clock source,
allowing system wide reduction of EMI of all clock
dependent signals. The ASM3P2779A allows significant
system cost savings by reducing the number of circuit
board layers, ferrite beads and shielding that are
traditionally required to pass EMI regulations.
The ASM3P2779A uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented by using a proprietary all digital method.
The ASM3P2779A 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 ASM3P2779A is targeted towards all portable
devices like MP3 players and digital still cameras.
Key Specifications
Description Specification
Supply voltages V
DD
= 3.3V / 2.5V
Cycle-to-Cycle Jitter ±200pS (Typ)
Output Duty Cycle 45/55%
Modulation Rate Equation F
IN
/640
Frequency Deviation ±1% (Typ) @ 16MHz
Block Diagram
ModOUT
VSS
XIN / CLKIN
Frequency
Divider
Feedback
Divider
Modulation
Phase
Detector
Loop
Filter
VCO
Output
Divider
PLL
VDD
PD
Crystal
Oscillator
XOUT
ASM3P2779A
Rev. 4 | Page 2 of 7 | www.onsemi.com
Pin Configuration (6L-TSOP 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.
Specifications
Description Specification
Frequency Range
For 2.5V Supply 13MHz < CLKIN < 30MHz
For 3.3V Supply 13MHz < CLKIN < 30MHz
Modulation Equation F
IN
/640
Frequency Deviation ±1% (Typ) @ 16MHz
Absolute Maximum Ratings
Symbol Parameter Rating Unit
VDD, V
IN
Voltage on any pin with respect to Ground -0.5 to +4.6 V
T
STG
Storage temperature -65 to +125 °C
T
A
Operating temperature 0 to +70 °C
T
s
Max. Soldering Temperature (10 sec) 260 °C
T
J
Junction Temperature 150 °C
T
DV
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.
Operating Conditions
Parameter Description Min Max Unit
VDD Supply Voltage 2.375 3.6 V
T
A
Operating Temperature (Ambient Temperature) -40 +85 °C
C
L
Load Capacitance 15 pF
C
IN
Input Capacitance 7 pF
XOUT
1
2
3
4
5
6
ASM3P2779A
PD
XIN / CLKIN
VDD
VSS
ASM3P2779A
Rev. 4 | Page 3 of 7 | www.onsemi.com
DC Electrical Characteristics for 2.5V Supply
Symbol
Parameter Min Typ Max Unit
V
IL
Input low voltage VSS-0.3 0.8 V
V
IH
Input high voltage 2.0 VDD+0.3 V
I
IL
Input low current -35 µA
I
IH
Input high current 35 µA
I
XOL
XOUT output low current (@ 0.5V, VDD = 2.5V) 3 mA
I
XOH
XOUT output high current (@ 1.8V, VDD = 2.5V) 3 mA
V
OL
Output low voltage (VDD = 2.5 V, I
OL
= 8mA) 0.6 V
V
OH
Output high voltage (VDD = 2.5 V, I
OH
= 8mA) 1.8 V
I
DD
Static supply current
1
2.0 uA
I
CC
Dynamic supply current (2.5V, 16MHz and no load) 3.0 mA
VDD Operating Voltage 2.375 2.5 2.625 V
t
ON
Power-up time (first locked cycle after power-up)
2
5 mS
Z
OUT
Output impedance 50 Ω
Notes: 1.
XIN / CLKIN pin and PD pin are pulled low.
2. V
DD
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 13 30 MHz
ModOUT Output frequency 13 30 MHz
f
d
Frequency Deviation
Input Frequency = 13MHz ±1.15
%
Input Frequency = 30MHz ±0.6
t
LH
1
Output rise time (measured from 0.7V to 1.7V) 0.7 1.4 1.8 nS
t
HL
1
Output fall time (measured from 1.7V to 0.7V) 0.4 0.9 1.1 nS
t
JC
Jitter (cycle-to-cycle) ±200 pS
t
D
Output duty cycle 45 50 55 %
Note: 1. t
LH
and t
HL
are measured into a capacitive load of 15pF.
P1-P3P4-P6P7-P7

ASM3P2779AF-06OR

Mfr. #:
Buy ASM3P2779AF-06OR
Manufacturer:
ON Semiconductor
Description:
Clock Generators & Support Products 13-30MHZ 2.5V/3.3V LP EMI
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
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