SiT9005
1 to 141 MHz EMI Reduction Oscillator
Features
Applications
Spread spectrum for EMI reduction
Wide spread % option
Center spread: from ±0.125% to ±2%, ±0.125% step size
Down spread: -0.25% to -4% with -0.25% step size
Spread profile option: Triangular, Hershey-kiss
Programmable rise/fall time for EMI reduction: 8 options,
0.25 to 40 ns
Any frequency between 1 MHz and 141 MHz accurate to
6 decimal places
100% pin-to-pin drop-in replacement to quartz-based XO’s
Excellent total frequency stability as low as ±20 ppm
Operating temperature from -40°C to 85°C.
Low power consumption of 4.0 mA typical at 1.8V
Pin1 modes: Standby, output enable, or spread disable
Fast startup time of 5 ms
LVCMOS output
Industry-standard packages
QFN: 2.0 x 1.6, 2.5 x 2.0, 3.2 x 2.5 mm
2
Contact
SiTime
for SOT23-5 (2.9 x 2.8 mm
2
)
RoHS and REACH compliant, Pb-free, Halogen-free
and Antimony-free
Surveillance camera
IP camera
Industrial motors
Flat panels
Multi function printers
PCI express
Electrical Specifications
Table 1. Electrical Characteristics
All Min and Max limits are specified over temperature and rated operating voltage with 15 pF output load unless otherwise stated.
Typical values are at 25°C and 3.3V supply voltage.
Parameters
Output Frequency Range
Symbol
Min.
Typ.
Max.
Unit
Condition
Frequency Range
f
1
–
141
MHz
Frequency Stability and Aging
Frequency Stability
F_stab
-20
-25
-50
Operating Temperature Range
T_use
-20
-40
Supply Voltage
Vdd
1.62
2.25
2.52
2.7
2.97
2.25
Current Consumption
OE Disable Current
Idd
I_OD
–
–
–
–
Standby Current
I_std
–
–
–
–
–
–
–
1.8
2.5
2.8
3.0
3.3
–
5.6
5.0
5.0
4.6
2.1
0.4
+20
+25
+50
+70
+85
1.98
2.75
3.08
3.3
3.63
3.63
6.5
5.5
6.5
5.2
4.3
1.5
ppm
ppm
ppm
°C
°C
V
V
V
V
V
V
mA
mA
mA
mA
µA
µA
No load condition, f = 40 MHz, Vdd = 2.5V to 3.3V
No load condition, f = 40 MHz, Vdd = 1.8V
f = 40 MHz, Vdd = 2.5V to 3.3V, OE = GND, Output in high-Z
state
f = 40 MHz, Vdd = 1.8V, OE = GND, Output in high-Z state
ST
= GND, Vdd = 2.5V to 3.3V, Output is weakly pulled down
ST
= GND, Vdd = 1.8V, Output is weakly pulled down
Inclusive of initial tolerance at 25°C, 1st year aging at 25°C, and
variations over operating temperature, rated power supply
voltage. Spread = Off.
Operating Temperature Range
Extended Commercial
Industrial
Supply Voltage and Current Consumption
Rev 1.0
September 25, 2017
www.sitime.com
SiT9005
1 to 141 MHz EMI Reduction Oscillator
Table 1. Electrical Characteristics (continued)
Parameters
Duty Cycle
Rise/Fall Time
Symbol
DC
Tr, Tf
Min.
45
–
–
–
Output High Voltage
VOH
90%
Typ.
–
1
1.3
–
–
Max.
55
2
2.5
2
–
Unit
%
ns
ns
ns
Vdd
Vdd = 2.5V, 2.8V, 3.0V or 3.3V, 20% - 80%, default derive
strength
Vdd =1.8V, 20% - 80%, default derive strength
Vdd = 2.25V - 3.63V, 20% - 80%, default derive strength
IOH = -4 mA (Vdd = 3.0V or 3.3V)
IOH = -3 mA (Vdd = 2.8V and Vdd = 2.5V)
IOH = -2 mA (Vdd = 1.8V)
IOL = 4 mA (Vdd = 3.0V or 3.3V)
IOL = 3 mA (Vdd = 2.8V and Vdd = 2.5V)
IOL = 2 mA (Vdd = 1.8V)
Condition
LVCMOS Output Characteristics
Output Low Voltage
VOL
–
–
10%
Vdd
Input Characteristics
Input High Voltage
Input Low Voltage
Input Pull-up Impedance
VIH
VIL
Z_in
70%
–
50
2
–
–
87
–
–
30%
150
–
Vdd
Vdd
kΩ
MΩ
Pin 1, OE or
ST
Pin 1, OE or
ST
Pin 1, OE logic high or logic low, or
ST
logic high
Pin 1,
ST
logic low
Startup and Resume Timing
Startup Time
Enable/Disable Time
Resume Time
Spread Enable Time
Spread Disable Time
Cycle-to-cycle jitter
T_start
T_oe
T_resume
T_sde
T_sdde
T_ccj
–
–
–
–
–
–
–
–
–
–
–
–
–
10.5
8.5
12.5
5
180
5
4
50
Jitter
15
12
22
ps
ps
ps
f = 40 MHz, Vdd = 2.5 to 3.3V, Spread = ON( or OFF)
f = 40 MHz, Vdd = 3.3V, Spread = ON( or OFF)
f = 40 MHz, Vdd = 1.8V, Spread = ON( or OFF)
ms
ns
ms
µs
µs
Measured from the time Vdd reaches its rated minimum value
f = 40 MHz. For other frequencies, T_oe = 100 ns + 3 * cycles
Measured from the time ST pin crosses 50% threshold
Measured from the time SD pin crosses 50% threshold
Measured from the time SD pin crosses 50% threshold
Table 2. Spread Spectrum %
[1,2]
Ordering
Code
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Center Spread
(%)
±0.125
±0.250
±0.390
±0.515
±0.640
±0.765
±0.905
±1.030
±1.155
±1.280
±1.420
±1.545
±1.670
±1.795
±1.935
±2.060
Down Spread
(%)
-0.25
-0.50
-0.78
-1.04
-1.29
-1.55
-1.84
-2.10
-2.36
-2.62
-2.91
-3.18
-3.45
-3.71
-4.01
-4.28
Table 3. Spread Profile
Spread Profile
Triangular
Hershey-kiss
Notes:
1. In both center spread and down spread modes, modulation rate
is employed with a frequency of ~31.25 kHz.
2. Contact
SiTime
for wider spread options
Rev 1.0
Page 2 of 9
www.sitime.com
SiT9005
1 to 141 MHz EMI Reduction Oscillator
Table 4. Pin Description
Pin
1
Symbol
OE /
ST
/
NC / SD
Output
Enable
Standby
[3]
Functionality
H : specified frequency output
L: output is high impedance. Only output driver is disabled.
H
[3]
: specified frequency output
L: output is low (week pull down). Device goes to sleep mode.
Supply current reduced to I_std.
Pin1 has no function (Any voltage between 0 and Vdd or Open)
H: Spread = ON
L: Spread = OFF
Electrical ground
Oscillator output
Power supply voltage
[4]
OE /
/
NC / SD
Top View
1
4
VDD
No
Connect
Spread
Disable
2
3
4
Notes:
GND
OUT
VDD
Power
Output
Power
GND
2
3
OUT
Figure 1. Pin Assignments
3. In OE or
ST
mode, a pull-up resistor of 10 kΩ or less is recommended if pin 1 is not externally driven. If pin 1 needs to be left floating, use the NC option.
4. A capacitor of value 0.1 µF or higher between Vdd and GND is required.
Table 5. Absolute Maximum Limits
Attempted operation outside the absolute maximum ratings may cause permanent damage to the part.
Actual performance of the IC is only guaranteed within the operational specifications, not at absolute maximum ratings.
Parameter
Storage Temperature
Vdd
Electrostatic Discharge
Soldering Temperature (follow standard Pb free
soldering guidelines)
Junction Temperature
[5]
Min.
-65
-0.5
–
–
–
Max.
150
4
2000
260
150
Unit
°C
V
V
°C
°C
Note:
5. Exceeding this temperature for extended period of time may damage the device.
Table 6. Maximum Operating Junction Temperature
[6]
Max Operating Temperature (ambient)
70°C
85°C
Maximum Operating Junction Temperature
80°C
95°C
Note:
6. Datasheet specifications are not guaranteed if junction temperature exceeds the maximum operating junction temperature.
Table 7. Environmental Compliance
Parameter
Mechanical Shock
Mechanical Vibration
Temperature Cycle
Solderability
Moisture Sensitivity Level
Condition/Test Method
MIL-STD-883F, Method 2002
MIL-STD-883F, Method 2007
JESD22, Method A104
MIL-STD-883F, Method 2003
MSL1 @ 260°C
Rev 1.0
Page 3 of 9
www.sitime.com
SiT9005
1 to 141 MHz EMI Reduction Oscillator
Timing Diagrams
Vdd
50% Vdd
T_resume
90% Vdd
Vdd
T_start
[7]
No Glitch
during start up
Pin 4 Voltage
ST Voltage
CLK Output
CLK Output
HZ
T_start: Time to start from power-off
HZ
T_resume: Time to resume from ST
Figure 2. Startup Timing
Figure 3. Standby Resume Timing
(ST Mode Only)
Vdd
50% Vdd
OE Voltage
T_oe
OE Voltage
Vdd
50% Vdd
T_oe
CLK Output
HZ
T_oe: Time to re-enable the clock output
CLK Output
HZ
T_oe: Time to put the output in High Z mode
Figure 4. OE Enable Timing (OE Mode Only)
Figure 5. OE Disable Timing (OE Mode Only)
Vdd
50% Vdd
SD Voltage
T_sde
SD Voltage
Vdd
50% Vdd
Frequency
Deviation (%)
T_sdde
Frequency
Deviation (%)
Modulation period = 32µs (31.25kHz)
Time (s)
Time (s)
Figure 6. SD Enable Timing (SD Mode Only)
Note:
7. SiT9005 has “no runt” pulses and “no glitch” output during startup or resume.
Figure 7. SD Diable Timing (SD Mode Only)
Rev 1.0
Page 4 of 9
www.sitime.com
SiT9005
1 to 141 MHz EMI Reduction Oscillator
Programmable Drive Strength
The SiT9005 includes a programmable drive strength feature
to provide a simple, flexible tool to optimize the clock rise/fall
time for specific applications. Benefits from the programmable
drive strength feature are:
The SiT9005 can support up to 60 pF or higher in maximum
capacitive loads with up to 3 additional drive strength settings.
Refer
to
the
Vdd
=
1.8V
Rise/Fall
Times
for Specific C
LOAD
to determine the proper drive strength for the
desired combination of output load vs. rise/fall time
SiT9005 Drive Strength Selection
Tables Table 1 through Table 12 define the rise/fall time for a
given capacitive load and supply voltage.
Select the table that matches the SiT9005 nominal
supply voltage (1.8V, 2.5V, 2.8V, 3.3V).
Select the capacitive load column that matches the
application requirement (15 pF to 60 pF)
Under the capacitive load column, select the desired
rise/fall times.
The left-most column represents the part number code
for the corresponding drive strength.
Add the drive strength code to the part number for
ordering purposes.
Improves system radiated electromagnetic interference
(EMI) by slowing down the clock rise/fall time
Improves the downstream clock receiver’s (RX) jitter by
decreasing (speeding up) the clock rise/fall time.
Ability to drive large capacitive loads while maintaining full
swing with sharp edge rates.
For more detailed information about rise/fall time control and
drive strength selection, see the SiTime Application Notes
section:
http://www.sitime.com/support/application-notes.
EMI Reduction by Slowing Rise/Fall Time
Figure 8 shows the harmonic power reduction as the rise/fall
times are increased (slowed down). The rise/fall times are
expressed as a ratio of the clock period. For the ratio of 0.05,
the signal is very close to a square wave. For the ratio of 0.45,
the rise/fall times are very close to near-triangular waveform.
These results, for example, show that the 11th clock harmonic
can be reduced by 35 dB if the rise/fall edge is increased from
5% of the period to 45% of the period.
Calculating Maximum Frequency
Based on the rise and fall time data given in Tables Table 1
through Table 12, the maximum frequency the oscillator can
operate with guaranteed full swing of the output voltage over
temperature as follows:
Max Frequency =
1
5 x Trf_20/80
where Trf_20/80 is the typical rise/fall time at 20% to 80% Vdd
Example 1
Calculate f
MAX
for the following condition:
Vdd = 3.3V (Table 12)
Capacitive Load: 30 pF
Desired Tr/f time = 1.6ns (rise/fall time part number code = Z)
Part number for the above example:
SiT9005AIZ14-33EB-105.12345
Figure 8. Harmonic EMI reduction as a Function
of Slower Rise/Fall Time
Drive strength code is inserted here. Default setting is “-”
Jitter Reduction with Faster Rise/Fall Time
Power supply noise can be a source of jitter for the
downstream chipset. One way to reduce this jitter is to
increase rise/fall time (edge rate) of the input clock. Some
chipsets would require faster rise/fall time in order to reduce
their sensitivity to this type of jitter. The SiT9005 provides up to
3 additional high drive strength settings for very fast rise/fall
time. Refer to the
Vdd = 1.8V Rise/Fall
Times
for Specific C
LOAD
to determine the proper drive strength.
High Output Load Capability
The rise/fall time of the input clock varies as a function of the
actual capacitive load the clock drives. At any given drive
strength, the rise/fall time becomes slower as the output load
increases. As an example, for a 3.3V SiT9005 device with
default drive strength setting, the typical rise/fall time is 1.1 ns
for 15 pF output load. The typical rise/fall time slows down to
2.9 ns when the output load increases to 45 pF. One can
choose to speed up the rise/fall time to 1.9 ns by then
increasing the drive strength setting on the SiT9005.
Rev 1.0
Page 5 of 9
www.sitime.com
maychang趣味电子技术课堂
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
