ON ASM3P2180A Peak reducing emi solution Datasheet

ASM3P2180A
Peak Reducing EMI Solution
Features
significant system cost savings by reducing the number
• Generates a 1x EMI optimized clock output.
of circuit board layers, and shielding that are traditionally
• Input frequency: 6MHz - 10MHz
required
to
pass
EMI
regulations.
ASM3P2180A
18MHz - 30MHz
modulates the output of a single PLL in order to
• Output frequency: 6MHz - 10MHz
“spread” the bandwidth of a synthesized clock, thereby
18MHz - 30MHz
decreasing the peak amplitudes of its harmonics. This
• Two selectable down spread options.
results in significantly lower system EMI compared to
• Selectable frequency range.
the typical narrow band signal produced by oscillators
• Integrated loop filter components.
and most clock generators. Lowering EMI by increasing
• Operates with a 3.3V supply.
a signal’s bandwidth is called spread spectrum clock
• CMOS design.
generation. ASM3P2180A uses the most efficient and
• 8-pin SOIC packages.
optimized modulation profile approved by the FCC and
is implemented by using a proprietary all-digital method.
Product Description
The ASM3P2180A is a versatile spread spectrum
Applications
frequency modulator designed specifically for a wide
The ASM3P2180A is targeted towards notebook LCD
range of clock frequencies. ASM3P2180A reduces
displays, other displays using an LVDS interface, PC
electromagnetic interference (EMI) at the clock source,
peripheral devices and embedded systems.
allowing system wide reduction of EMI of down stream
clock and data dependent signals. ASM3P2180A allows
Block Diagram
VDD
FS
Modulation
CLKIN / XIN
XOUT
SS%
CLKOUT
Crystal
Oscillator
PLL
GND
©2010 SCILLC. All rights reserved.
JANUARY 2010 – Rev. 2
Publication Order Number:
ASM3P2180/D
ASM3P2180A
Pin Diagram
CLKIN / XIN 1
8
XOUT 2
3P2180A
NC
7 FS
GND 3
6 VDD
SS% 4
5 CLKOUT
Pin Description
Pin#
Pin Name
Type
Description
1
CLKIN / XIN
I
Crystal connection or external reference clock input.
2
XOUT
O
Connection for an external crystal. If using an external reference, this pin must
be left unconnected.
3
GND
P
Ground to entire chip.
4
SS%
I
Spread Selection Input. Has an internal pull-up resistor.
5
CLKOUT
O
Modulated Clock Output.
6
VDD
P
Power supply for the entire chip.
7
FS
I
Frequency selection bit. This pin selects the frequency range of operation.
(Refer to the Frequency Range Selection Table). Has an internal pull-up
resistor.
8
NC
-
No connect.
Frequency Range Selection
FS
Frequency Range (MHz)
0
6-10
1
18-30
Spread Selection table
SS%
0
1
Frequency (MHz)
FS=0
FS=1
6
18
8
24
10
30
Deviation (%) (typ)
-2
-1.5
-1
6
8
18
24
-4
-3
10
30
-2
Rev. 2 | Page 2 of 6 | www.onsemi.com
ASM3P2180A
Absolute Maximum Ratings
Symbol
VDD, VIN
TSTG
Rating
Unit
Voltage on any pin with respect to Ground
Parameter
-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
Min
Max
Unit
Supply Voltage
2.8
3.7
V
TA
Operating Temperature (Ambient Temperature)
-40
+85
°C
CL
Load Capacitance
15
pF
CIN
Input Capacitance
7
pF
VDD
Description
DC Electrical Characteristics
Symbol
VIL
Parameter
Min
Typ
Max
Unit
V
Input low voltage
GND – 0.3
0.8
VIH
Input high voltage
2.0
VDD + 0.3
V
IIL
Input low current (pull-up resistors on inputs SS%, FS)
-27
µA
IIH
Input high current
18
µA
IXOL
XOUT output low current (@ 0.4V, VDD = 3.3V)
3
mA
IXOH
XOUT output high current (@2.5V, VDD = 3.3V)
4
mA
VOL
Output low voltage (VDD = 3.3V, IOL = 4mA)
VOH
2.5
IDD *
Output high voltage (VDD = 3.3V, IOH = 4mA)
Dynamic supply current normal mode (3.3V and 10pF
loading)
Static supply current standby mode
VDD
Operating voltage
2.8
tON
Power up time (first locked clock cycle after power up)
ICC
ZOUT
Clock output impedance
*CLKIN pin pulled to GND
Rev. 2 | Page 3 of 6 | www.onsemi.com
0.4
10
V
V
15
3.3
25
mA
7
mA
3.7
V
0.18
mS
50
Ω
ASM3P2180A
AC Electrical Characteristics
Symbol
CLKIN
CLKOUT
Parameter
Input frequency
Output frequency
Min
Typ
Max
FS=0
6
10
FS=1
18
30
FS=0
6
10
FS=1
18
30
Unit
MHz
MHz
tLH*
Output rise time (measured at 0.8V to 2.0V)
1.2
1.3
1.4
nS
tHL*
Output fall time (measured at 2.0V to 0.8V)
0.8
0.9
1.0
nS
tJC
Jitter (cycle to cycle)
tD
Output duty cycle
±325
45
50
*tLH and tHL are measured into a capacitive load of 15pF
Typical Test Circuit
+3.3V
Crystal
XIN
VDD
C1
0.1uF
XOUT
C2
CLKOUT
GND
CLOAD
Rev. 2 | Page 4 of 6 | www.onsemi.com
Spread spectrum
output
(EMI suppressed)
pS
55
%
ASM3P2180A
Package Information
8-Pin SOIC Package
H
E
D
A2
A
θ
C
D
e
A1
L
B
Dimensions
Symbol
Inches
Min
Max
Millimeters
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
θ
0°
8°
0.41
1.27
0°
8°
Rev. 2 | Page 5 of 6 | www.onsemi.com
ASM3P2180A
Ordering Codes
Part Number
Marking
Package Type
Temperature
ASM3P2180AF-08ST
ACT
8-pin SOIC, tube, Pb Free
0°C to +70°C
ASM3P2180AF-08SR
ACT
8-pin SOIC, tape and 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.
Licensed under US patent #5,488,627, #6,646,463 and #5,631,920.
Note: This product utilizes US Patent # 6,646,463 Impedance Emulator Patent issued to PulseCore Semiconductor, dated 11-11-2003
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes
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