SIT8918BA-23-33N-100.00000G 数据手册
SiT8918B
High Temperature Oscillator
Features
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Applications
Frequencies between 1 MHz and 110 MHz accurate
to 6 decimal places
Operating temperature from -40°C to 125°C.
For -55°C option, refer to SiT8920 and SiT8921
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Supply voltage of 1.8 V or 2.5 V to 3.3 V
Excellent total frequency stability as low as ±20 ppm
Low power consumption of 3.5 mA typical at 1.8 V
LVCMOS/LVTTL compatible output
Industry-standard packages: 2.0 x 1.6, 2.5 x 2.0,
3.2 x 2.5, 5.0 x 3.2, 7.0 x 5.0 mm x mm
Instant samples with Time Machine II and field
programmable oscillators
RoHS and REACH compliant, Pb-free, Halogen-free
and Antimony-free
For AEC-Q100 oscillators, refer to SiT8924 and
SiT8925
Industrial, medical, non AEC-Q100 automotive,
avionics and other high temperature applications
Industrial sensors, PLC, motor servo, outdoor
networking equipment, medical video cam, asset
tracking systems, etc.
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 nominal supply voltage.
Parameters
Symbol
Min.
Typ.
Max.
Unit
Condition
Frequency Range
Output Frequency Range
–
f
1
110
MHz
F_stab
-20
–
+20
ppm
-25
–
+25
ppm
-30
–
+30
ppm
-50
–
+50
ppm
Refer to Table 13 for the exact list of supported frequencies
list of supported frequencies.
Frequency Stability and Aging
Frequency Stability
Inclusive of Initial tolerance at 25°C, 1st year aging at 25°C, and
variations over operating temperature, rated power supply
voltage and load (15 pF ±10%).
Operating Temperature Range
Operating Temperature Range
(ambient)
T_use
-40
–
+105
°C
Extended Industrial
-40
–
+125
°C
Automotive
Supply Voltage and Current Consumption
Supply Voltage
Current Consumption
OE Disable Current
Standby Current
Rev 1.03
Vdd
Idd
I_od
I_std
1.62
1.8
1.98
V
2.25
2.5
2.75
V
2.52
2.8
3.08
V
2.7
3.0
3.3
V
2.97
3.3
3.63
V
2.25
–
3.63
V
–
3.8
4.7
mA
No load condition, f = 20 MHz, Vdd = 2.8 V, 3.0 V or 3.3 V
–
3.6
4.5
mA
No load condition, f = 20 MHz, Vdd = 2.5 V
–
3.5
4.5
mA
No load condition, f = 20 MHz, Vdd = 1.8 V
–
–
4.5
mA
Vdd = 2.5 V to 3.3 V, OE = Low, Output in high Z state
–
–
4.3
mA
Vdd = 1.8 V, OE = Low, Output in high Z state
–
2.6
8.5
A
Vdd = 2.8 V to 3.3 V, ST = Low, Output is weakly pulled down
–
1.4
5.5
A
Vdd = 2.5 V, ST = Low, Output is weakly pulled down
–
0.6
4.0
A
Vdd = 1.8 V, ST = Low, Output is weakly pulled down
March 15, 2021
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SiT8918B High Temperature Oscillator
Table 1. Electrical Characteristics (continued)
Parameters
Symbol
Min.
Typ.
Max.
Unit
Condition
Input Characteristics
Input High Voltage
VIH
70%
–
–
Vdd
Pin 1, OE or ST
Input Low Voltage
VIL
–
–
30%
Vdd
Pin 1, OE or ST
Input Pull-up Impedance
Z_in
50
87
150
k
Pin 1, OE logic high or logic low, or ST logic high
2
–
–
M
Pin 1, ST logic low
Startup and Resume Timing
Startup Time
T_start
–
–
5
ms
Measured from the time Vdd reaches its rated minimum value
T_oe
–
–
130
ns
f = 110 MHz.
For other frequencies, T_oe = 100 ns + 3 * clock periods
T_resume
–
–
5
ms
Measured from the time ST pin crosses 50% threshold
Enable/Disable Time
Resume Time
Jitter
RMS Period Jitter
T_jitt
Peak-to-peak Period Jitter
T_pk
RMS Phase Jitter (random)
T_phj
–
1.6
2.5
ps
f = 75 MHz, Vdd = 2.5 V, 2.8 V, 3.0 V or 3.3 V
–
1.9
3
ps
f = 75 MHz, Vdd = 1.8 V
–
12
20
ps
f = 75 MHz, Vdd = 2.5 V, 2.8 V, 3.0 V or 3.3 V
–
14
25
ps
f = 75 MHz,Vdd = 1.8 V
–
0.5
0.8
ps
f = 75 MHz, Integration bandwidth = 900 kHz to 7.5 MHz
–
1.3
2
ps
f = 75 MHz, Integration bandwidth = 12 kHz to 20 MHz
50
100
ps
f = 100 MHz, Vdd = 1.8 V, 2.5 V, 2.8 V, 3.0 V or 3.3 V,
10,000 cycles
10
30
ps
f = 100 MHz, Vdd = 1.8 V, 2.5 V, 2.8 V, 3.0 V or 3.3 V
Long Term Jitter
T_ltj
–
Cycle-to-cycle Jitter
T_ccj
–
LVCMOS Output Characteristics
Duty Cycle
Rise/Fall Time
DC
45
–
55
%
All Vdds
Tr, Tf
–
1.0
2.0
ns
Vdd = 2.5 V, 2.8 V, 3.0 V or 3.3 V, 20% - 80%
–
1.3
2.5
ns
Vdd =1.8 V, 20% - 80%
–
1.0
3
ns
Vdd = 2.25 V - 3.63 V, 20% - 80%
Output High Voltage
VOH
90%
–
–
Vdd
IOH = -4 mA (Vdd = 3.0 V or 3.3 V)
IOH = -3 mA (Vdd = 2.8 V or 2.5 V)
IOH = -2 mA (Vdd = 1.8 V)
Output Low Voltage
VOL
–
–
10%
Vdd
IOL = 4 mA (Vdd = 3.0 V or 3.3 V)
IOL = 3 mA (Vdd = 2.8 V or 2.5 V)
IOL = 2 mA (Vdd = 1.8 V)
Table 2. Pin Description
Pin
Symbol
Output Enable
1
OE/ST
̅ ̅ ̅ /NC
Functionality
H[1]: specified frequency output
L: output is high impedance. Only output driver is disabled.
Standby
H[1]: specified frequency output
L: output is low (weak pull down). Device goes to sleep mode. Supply
current reduces to I_std.
No Connect
Any voltage between 0 and Vdd or Open[1]: Specified frequency
output. Pin 1 has no function.
2
GND
Power
Electrical ground
3
OUT
Output
Oscillator output
4
VDD
Power
Power supply voltage[2]
Top View
OE/ST/NC
1
4
VDD
GND
2
3
OUT
Figure 1. Pin Assignments
Notes:
1. 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.
2. A capacitor of value 0.1 µF or higher between Vdd and GND is required.
Rev 1.03
Page 2 of 18
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SiT8918B High Temperature Oscillator
Table 3. Absolute Maximum Limits
Attempted operation outside the absolute maximum ratings of the part may cause permanent damage to the part. Actual
performance of the IC is only guaranteed within the operational specifications, not at absolute maximum ratings.
Min.
Max.
Unit
Storage Temperature
Parameter
-65
150
°C
Vdd
V
-0.5
4
Electrostatic Discharge
–
2000
V
Soldering Temperature (follow standard Pb free soldering guidelines)
–
260
°C
Junction Temperature[3]
–
150
°C
Note:
3. Exceeding this temperature for extended period of time may damage the device.
Table 4. Thermal Consideration[4]
Package
JA, 4 Layer Board (°C/W)
JA, 2 Layer Board (°C/W)
JC, Bottom (°C/W)
7050
142
273
30
5032
97
199
24
3225
109
212
27
2520
117
222
26
2016
152
252
36
Note:
4. Refer to JESD51-7 for JA and JC definitions, and reference layout used to determine the JA and JC values in the above table.
Table 5. Maximum Operating Junction Temperature[5]
Max Operating Temperature (ambient)
Maximum Operating Junction Temperature
105°C
115°C
125°C
135°C
Note:
5. Datasheet specifications are not guaranteed if junction temperature exceeds the maximum operating junction temperature.
Table 6. Environmental Compliance
Parameter
Condition/Test Method
Mechanical Shock
MIL-STD-883F, Method 2002
Mechanical Vibration
MIL-STD-883F, Method 2007
Temperature Cycle
JESD22, Method A104
Solderability
MIL-STD-883F, Method 2003
Moisture Sensitivity Level
MSL1 @ 260°C
Rev 1.03
Page 3 of 18
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SiT8918B High Temperature Oscillator
Test Circuit and Waveform[6]
Vdd
Vout
4
Power
Supply
Test Point
tr
3
80% Vdd
15pF
(including probe
and fixture
capacitance)
0.1 uF
2
1
tf
50%
20% Vdd
High Pulse
(TH)
Vdd
OE/ST Function
Low Pulse
(TL)
Period
1 kΩ
Figure 2. Test Circuit
Figure 3. Waveform
Note:
6. Duty Cycle is computed as Duty Cycle = TH/Period.
Timing Diagrams
90% Vdd
Vdd
Vdd
50% Vdd
[7]
T_start
Pin 4 Voltage
No Glitch
during start up
T_resume
ST Voltage
CLK Output
CLK Output
HZ
HZ
T_start: Time to start from power-off
T_resume: Time to resume from ST
Figure 4. Startup Timing (OE/ST Mode)
Figure 5. Standby Resume Timing (ST Mode Only)
Vdd
Vdd
50% Vdd
OE Voltage
50% Vdd
T_oe
OE Voltage
T_oe
CLK Output
CLK Output
HZ
HZ
T_oe: Time to put the output in High Z mode
T_oe: Time to re-enable the clock output
Figure 7. OE Disable Timing (OE Mode Only)
Figure 6. OE Enable Timing (OE Mode Only)
Note:
7. SiT8918 has “no runt” pulses and “no glitch” output during startup or resume.
Rev 1.03
Page 4 of 18
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SiT8918B High Temperature Oscillator
Performance Plots[8]
1.8 V
2.5 V
2.8 V
3V
3.3 V
6.0
DUT1
DUT2
DUT3
DUT4
DUT5
DUT6
DUT7
DUT8
DUT9
DUT10
DUT11
DUT12
DUT13
DUT14
DUT15
DUT16
DUT17
DUT18
DUT19
DUT20
25
5.5
20
15
Frequency (ppm)
Idd (mA)
5.0
4.5
4.0
3.5
10
5
0
-5
-10
-15
-20
3.0
-25
0
20
40
60
80
100
‐55
‐35
‐15
Frequency (MHz)
Figure 8. Idd vs Frequency
1.8 V
2.5 V
2.8 V
3.0 V
25
45
65
85
105
125
Figure 9. Frequency vs Temperature
3.3 V
1.8 V
2.5 V
2.8 V
3.0 V
3.3 V
55
4.0
54
3.5
53
3.0
52
Duty cycle (%)
RMS period jitter (ps)
5
Temperature (°C)
2.5
2.0
1.5
1.0
51
50
49
48
47
0.5
46
0.0
0
20
40
60
80
45
100
0
20
40
Frequency (MHz)
Figure 10. RMS Period Jitter vs Frequency
2.5 V
2.8 V
3.0 V
3.3 V
1.8 V
2.5
2.5
2.0
2.0
1.5
1.0
100
2.5 V
2.8 V
20
40
3.0 V
3.3 V
1.5
1.0
0.5
0.5
0.0
0.0
-40
-20
0
20
40
60
80
100
-40
120
-20
0
60
80
100
120
Temperature (°C)
Temperature (°C)
Figure 12. 20%-80% Rise Time vs Temperature
Rev 1.03
80
Figure 11. Duty Cycle vs Frequency
Fall time (ns)
Rise time (ns)
1.8 V
60
Frequency (MHz)
Figure 13. 20%-80% Fall Time vs Temperature
Page 5 of 18
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SiT8918B High Temperature Oscillator
Performance Plots[8] (continued)
1.8 V
2.5 V
2.8 V
3.0 V
3.3 V
1.8 V
2.5 V
2.8 V
3.0 V
3.3 V
1.0
2.0
1.9
0.9
1.8
0.8
IPJ (ps)
IPJ (ps)
1.7
1.6
1.5
1.4
1.3
0.7
0.6
0.5
1.2
0.4
1.1
1.0
0.3
10
20
30
40
50
60
70
80
90
100
110
10
Frequency (MHz)
20
30
40
50
60
70
80
90
100
110
Frequency (MHz)
Figure 15. RMS Integrated Phase Jitter Random
(900 kHz to 20 MHz) vs Frequency[9]
Figure 14. RMS Integrated Phase Jitter Random
(12 kHz to 20 MHz) vs Frequency[9]
Notes:
8. All plots are measured with 15 pF load at room temperature, unless otherwise stated.
9. Phase noise plots are measured with Agilent E5052B signal source analyzer. Integration range is 12 kHz to 5 MHz for carrier frequencies up to 40 MHz.
Rev 1.03
Page 6 of 18
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SiT8918B High Temperature Oscillator
then increasing the drive strength setting on the SiT8918.
Programmable Drive Strength
The SiT8918 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:
◼ 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 see the SiTime
Application Notes section.
The SiT8918 can support up to 60 pF or higher in
maximum capacitive loads with drive strength settings.
Refer to the Rise/Tall Time Tables (Tables 7 to 11) to
determine the proper drive strength for the desired
combination of output load vs. rise/fall time.
SiT8918 Drive Strength Selection
Tables 7 through 11 define the rise/fall time for a given
capacitive load and supply voltage.
1.
2.
3.
EMI Reduction by Slowing Rise/Fall Time
Figure 16 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 neartriangular 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.
5.
Calculating Maximum Frequency
Based on the rise and fall time data given in Tables 7
through 11, the maximum frequency the oscillator can
operate with guaranteed full swing of the output voltage
over temperature as follows:
trise=0.05
trise=0.1
trise=0.15
trise=0.2
trise=0.25
trise=0.3
trise=0.35
trise=0.4
trise=0.45
10
0
Harmonic amplitude (dB)
4.
-10
-20
Select the table that matches the SiT8918 nominal
supply voltage (1.8 V, 2.5 V, 2.8 V, 3.0 V, 3.3 V).
Select the capacitive load column that matches the
application requirement (5 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.
1
Max Frequency =
5 x Trf_20/80
-30
-40
where Trf_20/80 is the typical value for 20%-80% rise/fall time.
-50
-60
Example 1
-70
-80
1
3
5
7
9
11
Calculate fMAX for the following condition:
Harmonic number
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Figure 16. Harmonic EMI reduction as a Function of
Slower Rise/Fall Time
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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
speed up the rise/fall time of the input clock. Some chipsets
may also require faster rise/fall time in order to reduce their
sensitivity to this type of jitter. Refer to the Rise/Fall Time
Tables (Table 7 to Table 11) to determine the proper drive
strength.
Vdd = 1.8 V (Table 7)
Capacitive Load: 30 pF
Typical Tr/f time = 3 ns (rise/fall time part number code = E)
Part number for the above example:
SiT8918BE12-18E-66.666660
Drive strength code is inserted here. Default setting is “-”
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 3.3 V SiT8918
device with default drive strength setting, the typical rise/fall
time is 1 ns for 15 pF output load. The typical rise/fall time
slows down to 2.6 ns when the output load increases to 45 pF.
One can choose to speed up the rise/fall time to 1.83 ns by
Rev 1.03
Page 7 of 18
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SiT8918B High Temperature Oscillator
Rise/Fall Time (20% to 80%) vs CLOAD Tables
Table 7. Vdd = 1.8 V Rise/Fall Times
for Specific CLOAD
Table 9. Vdd = 2.5 V Rise/Fall Times
for Specific CLOAD
Rise/Fall Time Typ (ns)
Rise/Fall Time Typ (ns)
Drive Strength \ CLOAD
5 pF
15 pF
30 pF
45 pF
60 pF
Drive Strength \ CLOAD
5 pF
15 pF
30 pF
45 pF
60 pF
L
A
R
B
T
E
U
or "‐": default
6.16
3.19
2.11
1.65
0.93
0.78
0.70
0.65
11.61
6.35
4.31
3.23
1.91
1.66
1.48
1.30
22.00
11.00
7.65
5.79
3.32
2.94
2.64
2.40
31.27
16.01
10.77
8.18
4.66
4.09
3.68
3.35
39.91
21.52
14.47
11.08
6.48
5.74
5.09
4.56
L
A
R
B
T
E or "‐": default
U
F
4.13
2.11
1.45
1.09
0.62
8.25
4.27
2.81
2.20
1.28
12.82
7.64
5.16
3.88
2.27
21.45
11.20
7.65
5.86
3.51
27.79
14.49
9.88
7.57
4.45
0.54
0.43
0.34
1.00
0.96
0.88
2.01
1.81
1.64
3.10
2.79
2.54
4.01
3.65
3.32
Table 10. Vdd = 3.0 V Rise/Fall Times
for Specific CLOAD
Table 8. Vdd = 2.8 V Rise/Fall Times
for Specific CLOAD
Rise/Fall Time Typ (ns)
Rise/Fall Time Typ (ns)
Drive Strength \ CLOAD
5 pF
15 pF
30 pF
45 pF
60 pF
Drive Strength \ CLOAD
5 pF
15 pF
30 pF
45 pF
60 pF
L
A
R
B
T
E or "‐": default
U
F
3.77
1.94
1.29
0.97
0.55
0.44
0.34
0.29
7.54
3.90
2.57
2.00
1.12
1.00
0.88
0.81
12.28
7.03
4.72
3.54
2.08
1.83
1.64
1.48
19.57
10.24
7.01
5.43
3.22
2.82
2.52
2.29
25.27
13.34
9.06
6.93
4.08
3.67
3.30
2.99
L
A
R
B
T or "‐": default
E
U
F
3.60
1.84
1.22
0.89
0.51
0.38
0.30
0.27
7.21
3.71
2.46
1.92
1.00
0.92
0.83
0.76
11.97
6.72
4.54
3.39
1.97
1.72
1.55
1.39
18.74
9.86
6.76
5.20
3.07
2.71
2.40
2.16
24.30
12.68
8.62
6.64
3.90
3.51
3.13
2.85
Table 11. Vdd = 3.3 V Rise/Fall Times
for Specific CLOAD
Rise/Fall Time Typ (ns)
Drive Strength \ CLOAD
5 pF
15 pF
30 pF
45 pF
60 pF
L
A
R
B
3.39
1.74
1.16
0.81
6.88
3.50
2.33
1.82
11.63
6.38
4.29
3.22
17.56
8.98
6.04
4.52
23.59
12.19
8.34
6.33
T or "‐": default
E
U
F
0.46
0.33
0.28
0.25
1.00
0.87
0.79
0.72
1.86
1.64
1.46
1.31
2.60
2.30
2.05
1.83
3.84
3.35
2.93
2.61
Rev 1.03
Page 8 of 18
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SiT8918B High Temperature Oscillator
Pin 1 Configuration Options (OE, ST
̅ ̅ ̅ , or NC)
Pin 1 of the SiT8918 can be factory-programmed to support
three modes: Output enable (OE), standby (ST
̅ ̅ ̅ ) or No
Connect (NC). These modes can also be programmed with
the Time Machine using field programmable devices.
Output Enable (OE) Mode
In the OE mode, applying logic Low to the OE pin only
disables the output driver and puts it in Hi-Z mode. The core
of the device continues to operate normally. Power
consumption is reduced due to the inactivity of the output.
When the OE pin is pulled High, the output is typically
enabled in