SiT1552AI-JE-DCC-32.768 数据手册
SiT1552
Smallest (1.2 mm2), Ultra-Low Power, 32.768 kHz MEMS TCXO
Smallest (1.2mm2), Ultra-Low Power, 32.768 kHz MEMS TCXO
Features
Applications
32.768 kHz ±5, ±10, ±20 ppm frequency stability options
over temp
World’s smallest TCXO in a 1.5 x 0.8 mm CSP
Operating temperature ranges:
0°C to +70°C
-40°C to +85°C
Ultra-low power: 3.63V, or lower operating frequency
below 32 kHz.
When measuring the SiT1552 output frequency with a
frequency counter, it is important to make sure the counter's
gate time is >100 ms. The slow frequency of a 32kHz clock
will give false readings with faster gate times.
Power Supply Noise Immunity
In addition to eliminating external output load capacitors
common with standard XTALs, this device includes special
power supply filtering and thus, eliminates the need for an
external Vdd bypass-decoupling capacitor to keep the
footprint as small as possible. Internal power supply filtering is
designed to reject more than ±150 mV noise and frequency
components from low frequency to more than 10 MHz.
Rev 1.4
During initial power-up, the SiT1552 power-cycles internal
blocks, as shown in the power-supply start-up and steady
state plot in the Typical Operating Curves section. Power-up
and initialization is typically 200 ms, and during that time,
the peak supply current reaches 28 µA as the internal
capacitors are charged, then sequentially drops to its
990 nA steady-state current. During steady-state operation,
the internal temperature compensation circuit turns on
every 350 ms for a duration of approximately 10 ms.
Output Voltage
The SiT1552 has two output voltage options. One option is a
standard LVCMOS output swing. The second option is the
NanoDrive reduced swing output. Output swing is customer
specific and programmed between 200 mV and 800 mV. For
DC-coupled applications, output VOH and VOL are individually
factory programmed to the customers’ requirement. VOH
programming range is between 600 mV and 1.225V in
100 mV increments. Similarly, VOL programming range is
between 350 mV and 800 mV. For example; a PMIC or MCU
is internally 1.8V logic compatible, and requires a 1.2V V IH
and a 0.6V VIL. Simply select SiT1552 NanoDrive factory
programming code to be “D14” and the correct output
thresholds will match the downstream PMIC or MCU input
requirements. Interface logic will vary by manufacturer and
we recommend that you review the input voltage
requirements for the input interface.
For DC-biased NanoDrive output configuration, the minimum
VOL is limited to 350mV and the maximum allowable swing
(VOH - VOL) is 750 mV. For example, 1.1V VOH and 400 mV
VOL is acceptable, but 1.2V VOH and 400 mV VOL is not
acceptable.
When the output is interfacing to an XTAL input that is
internally AC-coupled, the SiT1552 output can be factory
programmed to match the input swing requirements.
For example, if a PMIC or MCU input is internally
AC-coupled and requires an 800 mV swing, then simply
choose the SiT1552 NanoDrive programming code “AA8”
in the part number. It is important to note that the SiT1552
does not include internal AC-coupling capacitors.
Please see the Part Number Ordering section at the end of
the datasheet for more information about the part number
ordering scheme.
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SiT1552
2
Smallest (1.2 mm ), Ultra-Low Power, 32.768 kHz MEMS TCXO
SiT1552 NanoDrive™
SiT1552 Full Swing LVCMOS Output
Figure 3 shows a typical output waveform of the SiT1552
(into a 10 pF load) when factory programmed for a 0.70V
swing and DC bias (VOH/VOL) for 1.8V logic:
The SiT1552 can be factory programmed to generate fullswing LVCMOS levels. Figure 4 shows the typical waveform
(Vdd = 1.8V) at room temperature into a 15 pF load.
Example:
NanoDrive™ part number coding: D14.
Example part number: SiT1552AI-JE-D14-32.768
VOH = 1.1V, VOL = 0.4V (V_sw = 0.70V)
Example:
LVCMOS output part number coding is always DCC
Figure 3. SiT1552AI-JE-D14-32.768
Output Waveform (10 pF load)
Example part number: SiT1552AI-JE-DCC-32.768
Figure 4. LVCMOS Waveform
(Vdd = 1.8V) into 15 pF Load
Table 4 shows the supported NanoDrive™ VOH, VOL
factory programming options.
Table 4. Acceptable VOH/VOL NanoDrive™ Levels
NanoDrive
VOH (V)
VOL (V)
Swing (mV)
Comments
D26
1.2
0.6
600 ±55
1.8V logic compatible
D14
1.1
0.4
700 ±55
1.8V logic compatible
D74
0.7
0.4
300 ±55
XTAL compatible
AA3
n/a
n/a
300 ±55
XTAL compatible
The values listed in Table 4 are nominal values at 25°C
and will exhibit a tolerance of ±55 mV across Vdd and
-40°C to 85°C operating temperature range.
Rev 1.4
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SiT1552
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Smallest (1.2 mm ), Ultra-Low Power, 32.768 kHz MEMS TCXO
Calculating Load Current
No Load Supply Current
Total Supply Current with Load
When calculating no-load power for the SiT1552, the core
and output driver components need to be added. Since the
output voltage swing can be programmed to minimize load
current, the output driver current is variable. Therefore,
no-load operating supply current is broken into two sections;
core and output driver. The equation is as follows:
To calculate the total supply current, including the load,
follow the equation listed below.
Total Current = Idd Core + Idd Output Driver + Load Current
Example 1: Full-swing LVCMOS
Vdd = 1.8V
Idd Core = 990n
Load Capacitance = 10pF
Idd Output Driver: (Cdriver)(Vout)(Fout) =
(3.5pF)(1.8V)(32768Hz) = 206nA
Load Current: (10pF)(1.8V)(32768Hz) = 590nA
Total Current = 990nA + 206nA + 590nA = 1.79µA
Total Supply Current (no load) = Idd Core + Idd Output Driver
Example 1: Full-swing LVCMOS
Vdd = 1.8V
Idd Core = 990nA (typ)
Voutpp = 1.8V
Idd Output Driver: (Cdriver)(Vout)(Fout) =
(3.5pF)(1.8V)(32768Hz) = 206nA
Supply Current = 990nA + 206nA = 1.2µA
Example 2: NanoDrive™ Reduced Swing
Vdd = 1.8V
Idd Core = 990nA
Load Capacitance = 10pF
Voutpp (D14): VOH – VOL = 1.1V - 0.4V = 700mV
Idd Output Driver: (Cdriver)(Vout)(Fout) =
(3.5pF)(0.7V)(32768Hz) = 80nA
Load Current: (10pF)(0.7V)(32.768kHz) = 229nA
Total Current = 990nA + 80nA + 229nA = 1.299µA
Example 2: NanoDrive™ Reduced Swing
Vdd = 1.8V
Idd Core = 990nA (typ)
Voutpp (D14) = VOH – VOL = 1.1V - 0.4V = 700mV
Idd Output Driver: (Cdriver)(Vout)(Fout) =
(3.5pF)(0.7V)(32768Hz) = 80nA
Supply Current = 990nA + 80nA = 1.07µA
Rev 1.4
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SiT1552
2
Smallest (1.2 mm ), Ultra-Low Power, 32.768 kHz MEMS TCXO
Typical Operating Curves
Frequency Stability (PPM)
(TA = 25°C, Vdd = 1.8V, unless otherwise stated)
Pre-reflow
5 ppm Option (E)
200 units
Post 3x-reflow
5 ppm Option (E)
200 units
Temperature (°C)
Figure 6. Frequency Stability Over
Temperature (Post-Reflow)
Output Stage Current (nA/Vpp)
Figure 5. Frequency Stability Over Temperature
(Pre-Reflow)
Vdd = 3.63V
Vdd = 1.5 – 1.8V
Vdd = 3.63V
Vdd = 1.5 – 1.8V
Temperature (°C)
No Load Current (µA)
Figure 7. Core Current Over Temperature
Figure 8. Output Stage Current Over
Temperature
Vdd = 3.63V
(6µA)
Vdd = 1.5 – 1.8V
0.99
Time from Power ON [ms]
Temperature (°C)
Figure 9. Total Supply Current Over Temperature,
LVCMOS (Core + LVCMOS Output Driver, No Load)
Rev 1.4
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Figure 10. Start-up and Steady-State Current
Profile
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Smallest (1.2 mm ), Ultra-Low Power, 32.768 kHz MEMS TCXO
Frequency Error (ppm)
SiT1552
Noise Injection Frequency (Hz)
Figure 11. Power Supply Noise Rejection (±150mV Noise)
Figure 12. Temperature Ramp Response
Figure 13. NanoDrive™ Output Waveform
(VOH = 1.1V, VOL = 0.4V; SiT1552AI-JE-D14-32.768)
Rev 1.4
Figure 14. LVCMOS Output Waveform
(Vswing = 1.8V, SIT1552AI-JE-DCC-32.768, 10 pF Load)
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SiT1552
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Smallest (1.2 mm ), Ultra-Low Power, 32.768 kHz MEMS TCXO
Dimensions and Patterns
Package Size – Dimensions (Unit: mm)
Recommended Land Pattern (Unit: mm)
#4
#3
#2
#1
(soldermask openings shown with
dashed line around NSMD pad)
Recommended 4-mil (0.1mm) stencil thickness
Rev 1.4
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SiT1552
2
Smallest (1.2 mm ), Ultra-Low Power, 32.768 kHz MEMS TCXO
Manufacturing Guidelines
1) No Ultrasonic Cleaning: Do not subject the SiT1552 to an ultrasonic cleaning environment. Permanent damage or long term
reliability issues to the MEMS structure may occur.
2) Do not apply underfill to the SiT1552. The device will not meet the frequency stability specification if underfill is applied.
3) Reflow profile, per JESD22-A113D.
4) For additional manufacturing guidelines and marking/tape-reel instructions, refer to: SiTime Manufacturing Notes.
Rev 1.4
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SiT1552
2
Smallest (1.2 mm ), Ultra-Low Power, 32.768 kHz MEMS TCXO
Ordering Information
Part number characters in blue represent the customer specific options. The other characters in the part number are fixed.
SiT1552AI-JE-DCC-32.768S
Part Family
Packaging
“SiT1552”
“S”: 8 mm Tape & Reel, 10ku reel
“D”: 8 mm Tape & Reel, 3ku reel
“E”: 8 mm Tape & Reel, 1ku reel
Revision Letter
“A”: is the revision
Blank for Bulk
Samples in cut Tape & Reel strips
Temperature Range
“C”: Commercial, 0 to 70ºC
Output Clock Frequency (kHz)
“I”: Industrial, -40 to 85ºC
32.768 kHz
Package Size
“J”: 1.5 mm x 0.8 mm CSP
Output Voltage Setting
DCC: LVCMOS Output
NanoDrive™ Reduced Swing Output
Refer to Table 5 for output setting options
Over Temperature Stability Options
“E”: ±5 ppm
“F”: ±10 ppm
“1”: ±20 ppm
“A”: AC-coupled signal path
“D”: DC-coupled signal path
The following examples illustrate how to select the appropriate temp range and output voltage requirements:
Example 1: SiT1552AI-JE-DCC-32.768
Example 2: SiT1552AC-JF-D14-32.768
Industrial temperature range
CSP package
5 ppm frequency stability over temp
Output swing requirements:
a)
b)
c)
d)
Output frequency = 32.769 kHz
“D” = DC-coupled receiver
“C” = LVCMOS output swing
“C” = LVCMOS output swing
Commercial temperature range
CSP package
10 ppm frequency stability over temp
Output swing requirements:
a)
b)
c)
d)
Output frequency = 32.769 kHz
“D” = DC-coupled receiver
“1” = VOH = 1.1V
“4” = VOL = 400mV
Table 5. Acceptable VOH/VOL NanoDrive™ Levels[4]
NanoDrive
VOH (V)
VOL (V)
Swing (mV)
D26
1.2
0.6
600 ±55
1.8V logic compatible
D14
1.1
0.4
700 ±55
1.8V logic compatible
D74
0.7
0.4
300 ±55
XTAL compatible
AA3
n/a
n/a
300 ±55
XTAL compatible
Comments
Note:
4. If these available options do not accommodate your application, contact SiTime for other NanoDrive options.
Rev 1.4
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SiT1552
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Smallest (1.2 mm ), Ultra-Low Power, 32.768 kHz MEMS TCXO
Table 6. Revision History
Version
Release Date
1.0
09/17/2014
Change Summary
Rev 0.9 Preliminary to Rev 1.0 Production Release
Updated start-up time specification
Added typical operating plots
Removed SOT23 and 2012 SMD package options
Added “no underfill” in frequency stability specification condition
Added Manufacturing Guidelines section
1.1
10/14/2014
Improved Start-up Time at Power-up spec
Added 5 pF LVCMOS rise/fall time spec
1.2
11/10/2014
Updated 5 pF LVCMOS rise/fall time spec
1.3
11/12/2015
Removed NanoDrive from EC Table and Ordering Info
1.31
01/18/2018
Updated SPL, page layout changes
1.32
03/15/2018
Updated POD (Package Outline Drawing)
Updated logo and company address, other page layout changes
1.4
04/12/2018
Added the NanoDrive sections
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Rev 1.4
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