20 ppm, Ultra-Low Power 32.768 kHz Quartz XTAL Replacement
The Smart Timing Choice
The Smart Timing Choice
Features
Applications
Small SMD package: 2.0 x 1.2 mm (2012)
[1]
Pin-compatible to 2012 XTAL SMD package
Fixed 32.768 kHz output frequency
<20 ppm frequency tolerance
Ultra-low power: <1 µA
Supports coin-cell or super-cap battery backup voltages
Vdd supply range: 1.5V to 3.63V over -40°C to +85°C
Oscillator output eliminates external load caps
Internal filtering eliminates external Vdd bypass cap
NanoDrive™ programmable output swing for lowest power
Pb-free, RoHS and REACH compliant
Mobile Phones
Tablets
Health and Wellness Monitors
Fitness Watches
Sport Video Cams
Wireless Keypads
Ultra-Small Notebook PC
Pulse-per-Second (pps) Timekeeping
RTC Reference Clock
Battery Management Timekeeping
Note:
1. For the smallest 32 kHz XO in CSP (1.2mm
2
), consider the SiT1532
Electrical Characteristics
Parameter
Fixed Output Frequency
Frequency Tolerance
[2]
Frequency Stability
25°C Aging
[3]
Symbol
Fout
F_tol
F_stab
Min.
Typ.
32.768
Max.
Unit
kHz
Condition
Frequency and Stability
Frequency Stability
20
75
100
250
-1
1.2
1.5
0.90
Core Operating Current
[4]
ppm
ppm
ppm
V
V
μA
μA/Vpp
ms
ms
T
A
= 25°C, post reflow, Vdd: 1.5V – 3.63V.
T
A
= -10°C to +70°C, Vdd: 1.5V – 3.63V.
T
A
= -40°C to +85°C, Vdd: 1.5V – 3.63V.
T
A
= -10°C to +70°C, Vdd: 1.2V – 1.5V.
1st Year
T
A
= -10°C to +70°C
T
A
= -40°C to +85°C
T
A
= 25°C, Vdd: 1.8V. No load
T
A
= -10°C to +70°C, Vdd max: 3.63V. No load
T
A
= -40°C to +85°C, Vdd max: 3.63V. No load
T
A
= -40°C to +85°C, Vdd: 1.5V – 3.63V. No load
T
A
= -40°C to +85°C, 0 to 90% Vdd
T
A
= -40°C ≤ T
A
≤ +50°C, valid output
T
A
= +50°C < T
A
≤ +85°C, valid output
1
3.63
3.63
1.3
1.4
0.065
0.125
100
180
300
450
Supply Voltage and Current Consumption
Operating Supply Voltage
Vdd
Idd
Idd_out
t_Vdd_
Ramp
t_start
Output Stage Operating Current
[4]
Power-Supply Ramp
Start-up Time at Power-up
[5]
Operating Temperature Range
Commercial Temperature
Industrial Temperature
T_use
-10
-40
70
85
°C
°C
Notes:
2. Measured peak-to-peak. Tested with Agilent 53132A frequency counter. Due to the low operating frequency, the gate time must be ≥100 ms to ensure an accurate
frequency measurement.
3. Stability is specified for two operating voltage ranges. Stability progressively degrades with supply voltage below 1.5V. Measured peak-to-peak. Inclusive of
Initial Tolerance at 25°C, and variations over operating temperature, rated power supply voltage and load.
4. Core operating current does not include output driver operating current or load current. To derive total operating current (no load), add core operating current +
(0.065 µA/V) * (peak-to-peak output Voltage swing).
5. Measured from the time Vdd reaches 1.5V.
SiTime Corporation
Rev 1.2
990 Almanor Avenue, Sunnyvale, CA 94085
(408) 328-4400
www.sitime.com
Revised November 25, 2014
SiT1533
20 ppm, Ultra-Low Power 32.768 kHz Quartz XTAL Replacement
The Smart Timing Choice
The Smart Timing Choice
Electrical Characteristics
(continued)
Parameter
Symbol
Min.
Typ.
100
48
90%
10%
200
48
0.20 to
0.80
0.60 to
1.225
0.35 to
0.80
-0.055
T_jitt
35
0.055
52
Max.
200
50
52
Unit
Condition
10-90% (Vdd), 15 pF load, Vdd = 1.5V to 3.63V
10-90% (Vdd), 5 pF load, Vdd ≥ 1.62V
Vdd: 1.5V – 3.63V. I
OH
= -10 μA, 15 pF
Vdd: 1.5V – 3.63V. I
OL
= 10 μA, 15 pF
30-70% (V
OL
/V
OH
), 10 pF Load
SiT1533 does not internally AC-couple. This output description
is intended for a receiver that is AC-coupled. See Table 2 for
acceptable NanoDrive swing options.
Vdd: 1.5V – 3.63V, 10 pF Load, I
OH
/ I
OL
= ±0.2 μA.
Vdd: 1.5V – 3.63V. I
OH
= -0.2 μA, 10 pF Load. See Table 1 for
acceptable V
OH
/V
OL
setting levels.
Vdd: 1.5V – 3.63V. I
OL
= 0.2 μA, 10 pF Load. See Table 1 for
acceptable V
OH
/V
OL
setting levels.
T
A
= -40°C to +85°C, Vdd = 1.5V to 3.63V.
Cycles = 10,000, T
A
= 25°C, Vdd = 1.5V – 3.63V
LVCMOS Output Option, T
A
= -40°C to +85°C, typical values are at T
A
= 25°C
Output Rise/Fall Time
Output Clock Duty Cycle
Output Voltage High
Output Voltage Low
Output Rise/Fall Time
Output Clock Duty Cycle
AC-coupled Programmable
Output Swing
DC-Biased Programmable
Output Voltage High Range
DC-Biased Programmable
Output Voltage Low Range
Programmable Output Voltage
Swing Tolerance
Period Jitter
tr, tf
DC
VOH
VOL
tf, tf
DC
V_sw
ns
%
V
V
ns
%
V
NanoDrive™ Programmable, Reduced Swing Output
VOH
VOL
V
V
V
ns
RMS
Pin Configuration
SMD
Pin
1
Symbol
NC
I/O
No Connect
Power Supply
Ground
Functionality
No Connect. Will not respond to any input signal. When interfacing to an MCU’s XTAL input
pins, this pin is typically connected to the receiving IC’s X Out pin. In this case, the SiT1533
will not be affected by the signal on this pin. If not interfacing to an XTAL oscillator, leave pin
1 floating (no connect).
Connect to ground. All GND pins must be connected to power supply ground.
Oscillator clock output. When interfacing to an MCU’s XTAL, the CLK Out is typically
connected to the receiving IC’s X IN pin. The SiT1533 oscillator output includes an internal
driver. As a result, the output swing and operation is not dependent on capacitive loading.
This makes the output much more flexible, layout independent, and robust under changing
environmental and manufacturing conditions.
Connect to power supply 1.5V ≤ Vdd ≤ 3.63V for operation over -40°C to +85°C temperature
range. Under normal operating conditions, Vdd does not require external bypass/decoupling
capacitor(s). Internal power supply filtering will reject more than ±150 mVpp with frequency
components through 10 MHz.
Contact factory for applications that require a wider operating supply voltage range.
2
GND
3
CLK Out
OUT
4
Vdd
Power Supply
SMD Package (Top View)
Vdd
4
NC
1
2
3
CLK Out
GND
Rev. 1.2
Page 2 of 11
www.sitime.com
SiT1533
20 ppm, Ultra-Low Power 32.768 kHz Quartz XTAL Replacement
The Smart Timing Choice
The Smart Timing Choice
System Block Diagram
MEMS Resonator
NC
Control
Regulators
Vdd
Trim
Prog
Prog
GND
Sustaining
Amp
Ultra-Low
Power
PLL
Divider
Ultra-Low
Power Driver
CLK Out
Figure 1.
Absolute Maximum
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
Continuous Power Supply Voltage Range (Vdd)
Short Duration Maximum Power Supply Voltage (Vdd)
Continuous Maximum Operating Temperature Range
Short Duration Maximum Operating Temperature Range
Human Body Model ESD Protection
Charge-Device Model (CDM) ESD Protection
Machine Model (MM) ESD Protection
Latch-up Tolerance
Mechanical Shock Resistance
Mechanical Vibration Resistance
2012 SMD Junction Temperature
Storage Temperature
≤30 minutes, over -40°C to +85°C
Vdd = 1.5V - 3.63V
Vdd = 1.5V - 3.63V, ≤30 mins
HBM, JESD22-A114
JESD220C101
T
A
= 25°C
JESD78 Compliant
Mil 883, Method 2002
Mil 883, Method 2007
10,000
70
150
-65°C to 150°C
g
g
°C
Test Condition
Value
-0.5 to 3.63
4.0
105
125
3000
750
300
Unit
V
V
°C
°C
V
V
V
Rev. 1.2
Page 3 of 11
www.sitime.com
SiT1533
20 ppm, Ultra-Low Power 32.768 kHz Quartz XTAL Replacement
The Smart Timing Choice
The Smart Timing Choice
Description
The SiT1533 is an ultra-small and ultra-low power 32.768 kHz
oscillator optimized for mobile and other battery-powered
applications. The SiT1533 is pin-compatible and footprint
compatible to existing 2012 XTALs when using the SiTime
solder-pad layout (SPL). And unlike standard oscillators, the
SiT1533 features NanoDrive™, a factory programmable
output that reduces the voltage swing to minimize power.
The 1.2V to 3.63V operating supply voltage range makes it an
ideal solution for mobile applications that incorporate a
low-voltage, battery-back-up source such as a coin-cell or
super-cap.
SiTime’s MEMS oscillators consist of MEMS resonators and a
programmable analog circuit. Our MEMS resonators are built
with SiTime’s unique MEMS First™ process. A key manufac-
turing step is EpiSeal™ during which the MEMS resonator is
annealed with temperatures over 1000°C. EpiSeal creates an
extremely strong, clean, vacuum chamber that encapsulates
the MEMS resonator and ensures the best performance and
reliability. During EpiSeal, a poly silicon cap is grown on top of
the resonator cavity, which eliminates the need for additional
cap wafers or other exotic packaging. As a result, SiTime’s
MEMS resonator die can be used like any other semicon-
ductor die. One unique result of SiTime’s MEMS First and
EpiSeal manufacturing processes is the capability to integrate
SiTime’s MEMS die with a SOC, ASIC, microprocessor or
analog die within a package to eliminate external timing
components and provide a highly integrated, smaller, cheaper
solution to the customer.
Frequency Stability
The SiT1533 is factory calibrated (trimmed) to guarantee
frequency stability to be less than 20 ppm at room temperature
and less than 100 ppm over the full -40°C to +85°C temper-
ature range. Unlike quartz crystals that have a classic tuning
fork parabola temperature curve with a 25°C turnover point,
the SiT1533 temperature coefficient is extremely flat across
temperature. The device maintains less than 100 ppm
frequency stability over the full operating temperature range
when the operating voltage is between 1.5 and 3.63V as
shown in Figure 3.
Functionality is guaranteed over the 1.2V - 3.63V operating
supply voltage range. However, frequency stability degrades
below 1.5V and steadily degrades as it approaches the 1.2V
minimum supply due to the internal regulator limitations.
Between 1.2V and 1.5V, the frequency stability is 250 ppm
max over temperature.
When measuring the SiT1533 output frequency with a
frequency counter, it is important to make sure the counter's
gate time is >100ms. The slow frequency of a 32 kHz clock will
give false readings with faster gate times.
For applications that require a wider supply voltage range
>3.63V, or operating frequency below 32 kHz, see the alter-
native 32 kHz product options on the SiTime web site;
www.sitime.com.
Frequency Stability (ppm)
SiT153x Industrial Temp Specification
SiT1533 20 ppm
Max @ 25C
XTAL Footprint Compatibility (SMD Package)
The SiT1533 is a replacement to the 32 kHz XTAL in the 2.0
x 1.2 mm (2012) package. Unlike XTAL resonators, SiTime’s
silicon MEMS oscillators require a power supply (Vdd) and
ground (GND) pin. Vdd and GND pins are conveniently placed
between the two large XTAL pins. When using the SiTime
Solder Pad Layout (SPL), the SiT1533 footprint is compatible
with existing 32 kHz XTALs in the 2012 SMD package. Figure
2 shows the comparison between the quartz XTAL footprint
and the SiTime footprint. For applications that require the
smallest footprint solution, consider the SiT1532 XO available
in a 1.2mm
2
CSP.
Quartz
SiTime
Connect to
X OUT or NC
1
SiT1533 Measured
Quartz XTAL
-160 to -220 ppm Over Temp
Temperature (°C)
Figure 3. SiTime vs. Quartz
Power Supply Noise Immunity
The SiT1533 is an ultra-small 32 kHz oscillator. 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. This feature further simplifies
the design and keeps the footprint as small as possible.
Internal power supply filtering is designed to reject AC-noise
greater than ±150 mVpp magnitude and beyond 10 MHz
frequency component.
X OUT
GND
2
4
3
VDD
X IN
Top View
Clock Out
Connect to X IN
Top View
Output Voltage
Figure 2. SiT1533 Footprint Compatibility with
Quartz XTAL Footprint
[6]
The SiT1533 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
Note:
6. On the Sitime device, X IN is not internally connected and will not respond to any signal. It is acceptable to connect to chipset X OUT.
Rev. 1.2
Page 4 of 11
www.sitime.com
SiT1533
20 ppm, Ultra-Low Power 32.768 kHz Quartz XTAL Replacement
The Smart Timing Choice
The Smart Timing Choice
DC-coupled applications, output V
OH
and V
OL
are individually
factory programmed to the customers’ requirement. V
OH
programming range is between 600 mV and 1.225V in 100 mV
increments. Similarly, V
OL
programming range is between 350
mV and 800 mV. For example; a PMIC or MCU is internally
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