ASM3P2872A D

ASM3P2872A
Peak EMI
Reducing Solution
Features
The ASM3P2872A uses the most efficient and optimized
• Generates an EMI optimized clock signal at the
modulation profile approved by the FCC and is
output.
implemented by using a proprietary all digital method.
• Integrated loop filter components.
The ASM3P2872A modulates the output of a single PLL
• Operates with a 3.3V / 2.5V supply.
in order to “spread” the bandwidth of a synthesized clock,
• Operating current less than 6mA.
and more importantly, decreases the peak amplitudes of
• CMOS design.
its harmonics. This results in significantly lower system
• Input frequency range: 13MHz to 30MHz for 2.5V
EMI compared to the typical narrow band signal produced
13MHz to 30MHz for 3.3V
by oscillators and most frequency generators. Lowering
• Generates a 1X low EMI spread spectrum clock of
EMI by increasing a signal’s bandwidth is called ‘spread
the input frequency.
spectrum clock generation.’
• Frequency deviation: -1.25% @ 22MHz.
• Available in 6L-TSOP (6L-TSOT-23) packages.
Applications
The ASM3P2872A is targeted towards all portable
Product Description
The ASM3P2872A is a versatile spread spectrum
frequency modulator designed specifically for a wide
range of clock frequencies. The ASM3P2872A reduces
electromagnetic interference (EMI) at the clock source,
allowing system wide reduction of EMI of all clock
dependent signals. The ASM3P2872A 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.
Block Diagram
devices like MP3 players, Notebooks and digital still
cameras.
Key Specifications
Description
Specification
Supply voltages
VDD = 3.3V /2.5V
Cycle-to-Cycle Jitter
±200pS (Typ)
Output Duty Cycle
45/55% (worst case)
Modulation Rate Equation
FIN/640
Frequency Deviation
-1.25% @ 22MHz
VDD
PLL
Modulation
XIN
XOUT
Crystal
Oscillator
Frequency
Divider
Feedback
Divider
REFOUT
Phase
Detector
Loop
Filter
VCO
Output
Divider
ModOUT
VSS
©2010 SCILLC. All rights reserved.
OCTOBER 2010 – Rev. 2.1
Publication Order Number:
ASM3P2872/D
ASM3P2872A
Pin Configuration (6L-TSOP Package)
REFOUT
1
XOUT
2
ASM3P2872A
XIN/CLKIN 3
6
VSS
5
ModOUT
4
VDD
Pin Description
Pin#
Pin Name
Type
Description
1
REFOUT
O
Buffered output of the input frequency.
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.
Modulation Profile
Specifications
Description
Frequency Range
Specification
For 2.5V Supply
For 3.3V Supply
13MHz < CLKIN < 30MHz
13MHz < CLKIN < 30MHz
Modulation Equation
FIN/640
Frequency Deviation
-1.25% @ 22MHz
Rev. 2 | Page 2 of 8 | www.onsemi.com
ASM3P2872A
Absolute Maximum Ratings
Symbol
VDD, VIN
TSTG
Parameter
Rating
Unit
Voltage on any pin with respect to Ground
-0.5 to +4.6
V
Storage temperature
-65 to +125
°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.
Operating Conditions
Parameter
VDD
Description
Supply Voltage
Min
Max
Unit
2.375
3.6
V
0
70
°C
TA
Operating Temperature (Ambient Temperature)
CL
Load Capacitance
15
pF
CIN
Input Capacitance
7
pF
DC Electrical Characteristics for 2.5V Supply
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)
VOH
Output high voltage (VDD = 2.5 V, IOH = 8mA)
IDD
Static supply current
ICC
Dynamic supply current (2.5V, 30MHz and with no load)
VDD
tON
ZOUT
0.6
1.8
1
Operating voltage
2.375
V
1.1
mA
4.0
mA
2.5
Power-up time (first locked cycle after power-up)
Output impedance
50
Note: 1. XIN / CLKIN pin is pulled low.
Rev. 2 | Page 3 of 8 | www.onsemi.com
V
2.625
V
5
mS
Ω
ASM3P2872A
AC Electrical Characteristics for 2.5V Supply
Symbol
CLKIN
ModOUT
fd
Min
Typ
Max
Unit
Input frequency
13
30
MHz
Output frequency
13
30
MHz
Frequency Deviation
Input Frequency = 13MHz
-1.85
Input Frequency = 30MHz
-0.9
%
1
Output rise time (measured from 0.7V to 1.7V)
0.7
1.5
1.7
nS
1
Output fall time (measured from 1.7V to 0.7V)
0.5
0.9
1.1
nS
tLH
tHL
Parameter
tJC
Jitter (cycle-to-cycle)
tD
Output duty cycle
±200
45
50
Min
Typ
pS
55
%
Note: 1. tLH and tHL are measured into a capacitive load of 15pF.
DC Electrical Characteristics for 3.3V Supply
Symbol
Parameter
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)
VOH
Output high voltage (VDD = 3.3 V, IOH = 8mA)
0.4
2.5
1
V
V
IDD
Static supply current
1.2
mA
ICC
Dynamic supply current (3.3V, 30MHz and with no load)
5.5
mA
VDD
tON
ZOUT
Operating voltage
2.7
3.3
Power-up time (first locked cycle after power-up)
Output impedance
45
Note: 1. XIN / CLKIN pin is pulled low.
Rev. 2 | Page 4 of 8 | www.onsemi.com
3.6
V
5
mS
Ω
ASM3P2872A
AC Electrical Characteristics for 3.3V Supply
Symbol
CLKIN
ModOUT
fd
Min
Typ
Max
Unit
Input frequency
13
30
MHz
Output frequency
13
30
MHz
Frequency Deviation
Input Frequency = 13MHz
-1.85
Input Frequency = 30MHz
-0.9
%
1
Output rise time (measured from 0.8 to 2.0V)
0.5
1.4
1.7
nS
1
Output fall time (measured at 2.0V to 0.8V)
0.4
0.9
1.1
nS
tLH
tHL
Parameter
tJC
Jitter (cycle-to-cycle)
tD
Output duty cycle
±200
45
50
pS
55
Note: 1. tLH and tHL are measured into a capacitive load of 15pF.
Typical Crystal Specifications
Fundamental AT cut parallel resonant crystal
Nominal frequency
14.31818MHz
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(CP)
18pF
Shunt capacitance
7pF maximum
ESR
25 Ω
Note: Note: CL is Load Capacitance and Rx is used to prevent oscillations at overtone frequency of the Fundamental frequency.
Typical Crystal Interface Circuit
R
Crystal
CL
Rx
CL
CL = 2*(CP – CS),
Where CP = Load capacitance of crystal
CS = Stray capacitance due to CIN, PCB, Trace etc.
Rev. 2 | Page 5 of 8 | www.onsemi.com
%
ASM3P2872A
Typical Application Schematic
VDD
C1
0.1µF
C2
2.2µF
VDD
ASM3P2872A
Rs
ModOUT
VSS
Rev. 2 | Page 6 of 8 | www.onsemi.com
ModOUT Clock
ASM3P2872A
Package Information
6L-TSOP Package
Dimensions
Symbol
Inches
Min
A
Max
Millimeters
Min
Max
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°
Rev. 2 | Page 7 of 8 | www.onsemi.com
ASM3P2872A
Ordering Information
Part Number
ASM3P2872AF-06OR
Marking
B4L
Package Type
Temperature
6L-TSOP (6L-TSOT-23), TAPE & REEL, Pb Free
0°C to +70°C
A “microdot” placed at the end of last row of marking or just below the last row toward the center of package indicates Pb-free.
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