DATASHEET
SPREAD SPECTRUM CLOCK SYNTHESIZER
Description
The IDT5P50901/2/3/4 is a family of 1.8V low power, spread
spectrum clock generators capable of reducing EMI
radiation from an input clock. Spread spectrum technique is
capable of reducing the harmonic frequency amplitude
peaks by several dB.
IDT5P50901/2/3/4
Features
•
8-pin DFN package (2x2mm)
8-pin MSOP package (3x4.9mm)
Ordering Information
Input Frequency
10 to 25 MHz - 5P50901NBGI/5P50901DVGI
20 to 50 MHz - 5P50902NBGI/5P50902DVGI
40 to 100 MHz - 5P50903NBGI/5P50903DVGI
80 to 170 MHz - 5P50904NBGI/5P50904DVGI
•
•
•
•
•
Provides a spread spectrum output clock
Input frequency range of 10 to 170 MHz
Output frequency range of 10 to 170 MHz
Center and down spread
Peak reduction by 8 dB to 16 dB typical on 3rd through
19th odd harmonics
•
Low EMI feature can be disabled
•
Operating voltage of 1.8 V, 2.5 or 3.3V
•
RoHS 6 compliant package
Spread Modulation Frequency Table
Part
Number
Input
(MHz)
Modulation
(kHz)
Input
(MHz)
Modulation
(kHz)
Modulation
Frequency (kHz)
5P50901
5P50902
5P50903
5P50904
10
20
40
80
27
27
27
27
25
50
100
170
67.5
67.5
67.5
57.4
ICLK*27/10000
ICLK*27/20000
ICLK*27/40000
ICLK*27/80000
Block Diagram
VDD
2
ICLK
S2:S0
PLL Clock
Synthesizer with
Spread Spectrum
Circuitry
CLKOUT
GND
IDT®
SPREAD SPECTRUM CLOCK SYNTHESIZER
1
IDT5P50901/2/3/4
REV F 082112
IDT5P50901/2/3/4
SPREAD SPECTRUM CLOCK SYNTHESIZER
CLOCK SYNTHESIZER
Pin Assignment
ICLK
VDD
S0
S1
4
5
1
8
VDD
CLKOUT
GND
S2
8-pin DFN
Spread Direction and Percentage Select Table
S2
S1
S0
Spread
Direction
Spread
Percentage
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
OFF
Center
Center
Center
Center
Center
Down
Down
--
±0.25
±0.5
±1.0
±1.5
±2.0
-0.5
-1.0
Pin Description
Pin
Number
Pin
Name
Pin Type
Pin Description
1
2
3
4
5
6
7
8
ICLK
VDD
S0
S1
S2
GND
CLKOUT
VDD
Input
Power
Input
Input
Input
Power
Output
Power
Input clock.
Voltage supply. Connect to 1.8 V ±0.1 V, 2.5 V ±10% or 3.3 V ±10%,
Function select 0 input. Selects spread amount and direction per table above.
Internal pull-down resistor.
Function select 1 input. Selects spread amount and direction per table above.
Internal pull-down resistor.
Function select 2 input. Selects spread amount and direction per table above.
Internal pull-down resistor.
Connect to ground.
Clock output.
Voltage supply. Connect to 1.8 V ±0.1 V, 2.5 V ±10% or 3.3 V ±10%
IDT®
SPREAD SPECTRUM CLOCK SYNTHESIZER
2
IDT5P50901/2/3/4
REV F 082112
IDT5P50901/2/3/4
SPREAD SPECTRUM CLOCK SYNTHESIZER
CLOCK SYNTHESIZER
External Components
Decoupling Capacitor
As with any high-performance mixed-signal IC, the
IDT5P50901/2/3/4 must be isolated from system power
supply noise to perform optimally.
A decoupling capacitor of 0.01µF must be connected
between each VDD and the PCB ground plane.
PCB Layout Recommendations
For optimum device performance and lowest output phase
noise, the following guidelines should be observed.
1) The 0.01µF decoupling capacitors should be mounted on
the component side of the board as close to the VDD pin as
possible. No vias should be used between the decoupling
capacitors and VDD pins. The PCB trace to VDD pins
should be kept as short as possible, as should the PCB
trace to the ground via.
2) To minimize EMI, the 33Ω series termination resistor (if
needed) should be placed close to the clock output.
3) An optimum layout is one with all components on the
same side of the board, minimizing vias through other signal
layers. Other signal traces should be routed away from the
IDT5P50901/2/3/4. This includes signal traces just
underneath the device, or on layers adjacent to the ground
plane layer used by the device.
Series Termination Resistor
Clock output traces over one inch should use series
termination. To series terminate a 50Ω trace (a commonly
used trace impedance), place a 33Ω resistor in series with
the clock line, as close to the clock output pin as possible.
The nominal impedance of the clock output is 20Ω.
External Clock Input
This device operates from an external clock input and as
such does not have a on chip oscillator circuit.
Spread Spectrum Profile
The IDT5P50901/2/3/4 is a low EMI clock generator using
an optimized frequency slew rate algorithm to facilitate down
stream tracking of zero delay buffers and other PLL devices.
The modulation rate is directly relate to the input clock
frequency.
For input frequency ICLK, then use the modulation
frequency indicated for the part below.
Modulation R
ate
Frequency
Time
IDT®
SPREAD SPECTRUM CLOCK SYNTHESIZER
3
IDT5P50901/2/3/4
REV F 082112
IDT5P50901/2/3/4
SPREAD SPECTRUM CLOCK SYNTHESIZER
CLOCK SYNTHESIZER
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the IDT5P50901/2/3/4. These ratings,
which are standard values for IDT commercially rated parts, are stress ratings only. Functional operation of the
device at these or any other conditions above those indicated in the operational sections of the specifications is not
implied. Exposure to absolute maximum rating conditions for extended periods can affect product reliability.
Electrical parameters are guaranteed only over the recommended operating temperature range.
Item
Supply Voltage, VDD
All Inputs
Ambient Operating Temperature
Storage Temperature
Junction Temperature
Soldering Temperature
-0.5 V to 5.0 V
Rating
-0.5 V to VDD +0.5 V
-40 to +85° C
-50 to +150° C
125° C
260° C
Recommended Operation Conditions
Parameter
Ambient Operating Temperature
Power Supply Voltage VDD (measured in respect to GND)
Min.
-40
+1.7
+2.25
+2.97
Typ.
+1.8
+2.5
+3.3
Max.
+85
+1.9
+2.75
+3.63
Units
°
C
V
V
V
IDT®
SPREAD SPECTRUM CLOCK SYNTHESIZER
4
IDT5P50901/2/3/4
REV F 082112
IDT5P50901/2/3/4
SPREAD SPECTRUM CLOCK SYNTHESIZER
CLOCK SYNTHESIZER
DC Electrical Characteristics
Unless stated otherwise,
VDD = 1.8 V ±0.1 V.
Ambient Temperature -40 to +85° C
Parameter
Operating Voltage
Input High Voltage
Input Low Voltage
Output High Voltage
Output Low Voltage
IDD
Input Capacitance
Load Capacitance
Internal Pull-down
Resistor
Symbol
VDD
V
IH
V
IL
V
OH
V
OL
Conditions
ICLK, S2:S0
ICLK, S2:S0
I
OH
= -12 mA
I
OL
= 12 mA
No load
Min.
1.7
VDD x 0.8
GND
VDD x 0.75
Typ.
1.8
Max.
1.9
VDD + 0.3
VDD x 0.2
Units
V
V
V
V
V
pF
pF
VDD
GND
5
5
VDD x 0.25
See table page 6
R
PD
S1:S0
200
260
kΩ
Unless stated otherwise,
VDD = 2.5 V ±10%.
Ambient Temperature -40 to +85° C
Parameter
Operating Voltage
Input High Voltage
Input Low Voltage
Output High Voltage
Output Low Voltage
IDD
Input Capacitance
Load Capacitance
Internal Pull-down
Resistor
Symbol
VDD
V
IH
V
IL
V
OH
V
OL
Conditions
ICLK, S2:S0
ICLK, S2:S0
I
OH
= -25 mA
I
OL
= 25 mA
No load
Min.
2.25
VDD x 0.8
GND
VDD x 0.9
Typ.
2.5
Max.
2.75
VDD + 0.3
VDD x 0.2
Units
V
V
V
V
V
pF
pF
VDD
GND
5
5
VDD x 0.1
See table page 6
R
PD
S1:S0
200
260
kΩ
Unless stated otherwise,
VDD = 3.3 V ±10%.
Ambient Temperature -40 to +85° C
Parameter
Operating Voltage
Input High Voltage
Input Low Voltage
Output High Voltage
Output Low Voltage
IDD
Input Capacitance
Load Capacitance
Internal Pull-down
Resistor
Symbol
VDD
V
IH
V
IL
V
OH
V
OL
Conditions
ICLK, S2:S0
ICLK, S2:S0
I
OH
= -33 mA
I
OL
= 33 mA
No load
Min.
2.97
VDD x 0.8
GND
VDD x 0.9
Typ.
3.3
Max.
3.63
VDD + 0.3
VDD x 0.2
Units
V
V
V
V
V
pF
pF
VDD
GND
5
5
VDD x 0.1
See table page 6
R
PD
S1:S0
200
260
kΩ
IDT®
SPREAD SPECTRUM CLOCK SYNTHESIZER
5
IDT5P50901/2/3/4
REV F 082112
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