The Smart Timing Choice
The Smart Timing Choice
SiTime Corporation 990 Almanor Avenue Sunnyvale, CA 94085 (408) 328-4400 www.sitime.com
Rev 0.77 Revised July 18, 2013
SiT1533
Ultra-Low Power 32.768 kHz XTAL Replacement in 2.0 x 1.2 mm SMD
Preliminary
Notes:
2. Stability is specified for two operating voltage ranges. Stability progressively degrades with supply voltage below 1.5V.
3. Core operating current does not include output driver operating current or load current.
4. To derive total operating current (no load), add core operating current + (0.065 µA/V) * (peak-to-peak output Voltage swing).
Features Applications
Small SMD package: 2.0 x 1.2 mm (2012)[1] Mobile Phones
Pin-compatible to 2012 XTAL SMD package Tablets
Ultra-low power: <1µA Health and Wellness Monitors
Supports coin-cell or super-cap battery backup voltages Fitness Watches
Vdd supply range: 1.5V to 3.63V over -40°C to +85°C Sport Video Cams
Oscillator output eliminates external load caps Wireless Keypads
NanoDrive™ programmable output swing for lowest power Ultra-Small Notebook PC
Internal filtering eliminates external Vdd bypass cap Pulse-per-Second (pps) Timekeeping
Fixed 32.768 kHz output frequency RTC Reference Clock
<20 PPM initial stability Battery Management Timekeeping
<100 PPM stability over -40°C to +85°C
Pb-free, RoHS and REACH compliant
Note: 1. For the smallest 32 kHz XO in CSP (1.2mm2), consider the SiT1532
Electrical Characteristics
Parameter Symbol Min. Typ. Max. Unit Condition
Frequency and Stability
Fixed Output Frequency Fout 32.768 kHz
Frequency Stability
Frequency Stability [2] F_stab
20
PPM
TA = 25°C, Vdd: 1.5V – 3.63V
75 TA = -10°C to +70°C, Vdd: 1.5V – 3.63V. Stability includes initial,
power supply, and temperature stability components.
100 TA = -40°C to +85°C, Vdd: 1.5V – 3.63V. Stability includes initial,
power supply, and temperature stability components.
250 TA = 10°C to +70°C, Vdd: 1.2V – 1.5V. Stability includes initial,
power supply, and temperature stability components.
25°C Aging -3 3 PPM 1st Year
Supply Voltage and Current Consumption
Operating Supply Voltage Vdd 1.2 3.63 V TA = 10°C to +70°C
1.5 3.63 V TA = -40°C to +85°C
Power Supply Reset Voltage Reset 0.3 V
Core Operating Current [3, 4] Idd
0.9
μA
TA = 25°C, Vdd: 1.5V – 3.63V. No load
1.3 TA = -10°C to +70°C, Vdd max: 3.63V. No load
1.35 TA = -40°C to +85°C, Vdd max: 3.63V. No load
Output Stage Operating Current
[3]
Idd_out 0.065 0.125 μA/Vpp TA = -40°C to +85°C, Vdd: 1.5V – 3.63V. No load
Power-Supply Ramp t_Vdd_
Ramp 100 ms TA = -40°C to +85°C, 0 to 100% Vdd
TSTART-UP at Power-up T_start 150 300 ms TA = -40°C to +85°C
Operating Temperature Range
Commercial Temperature T_use -10 70 °C
Industrial Temperature -40 85 °C
LVCMOS Output Option, TA = -40°C to +85°C, typical value is TA = 25°C
Output Rise/Fall Time tr, tf 100 200 ns 10-90%, 15 pF load, Vdd = 1.5V to 3.63V
Output Clock Duty Cycle DC 48 52 %
Output Voltage High VOH 90% V Vdd: 1.5V – 3.63V. IOH = -10μA, 15 pF
Output Voltage Low VOL 10% V Vdd: 1.5V – 3.63V. IOL = 10μA, 15 pF
NanoDrive™ Programmable, Reduced Swing Output
Output Rise/Fall Time tf, tf 200 ns 10-90%, 15 pF Load
Output Clock Duty Cycle DC 48 52 %
AC-coupled Programmable
Output Swing V_sw 0.25 0.80 V Vdd: 1.2V – 3.63V, 15 pF Load, 10 pF, IOH / IOL = ±0.2uA
DC-Biased Programmable
Output Voltage High Range VOH 0.5 1.20 V Vdd: 1.2V – 3.63V. IOH = -0.2μA, 10 pF Load
DC-Biased Programmable
Output Voltage Low Range VOL 0.35 0.80 V Vdd: 1.2V – 3.63V. IOH = 0.2μA, 10 pF Load
The Smart Timing Choice
The Smart Timing Choice
SiT1533
Ultra-Low Power 32.768 kHz XTAL Replacement in 2.0 x 1.2 mm SMD
Rev. 0.77 Page 2 of 7 www.sitime.com
System Block Diagram
Figure 1.
Electrical Characteristics (continued)
Parameter Symbol Min. Typ. Max. Unit Condition
Jitter Performance (TA = 25°C, Vdd = 1.5V to 2.0V, unless otherwise stated)
Period Jitter T_djitt 45 nsRMS N = 10,000
Pin Configuration
Pin Symbol I/O Functionality
1NC
No Connect,
don’t care
No Connect. Will not respond to any input signal. 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.
2GND
Power Supply
Ground Connect to ground.
3CLK Out OUT
Oscillator clock output. 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 environ-
mental and manufacturing conditions.
4 Vdd Power Supply
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).
Contact factory for applications that require a wider operating supply
voltage range.
Absolute Maximum
Attempted operation outside the absolute maximum ratings of the part may cause permanent damage to the part. Actual perfor-
mance of the IC is only guaranteed within the operational specifications, not at absolute maximum ratings.
Parameter Symbol Test Condition Value Unit
Power Supply Voltage Range (Vdd) Vdd -0.5 to 4
ESD Protection HBM 100pF, 1.5k2000
ESD Protection CDM, 25°C 750
ESD Protection MM, 25°C 200
Power Supply Voltage Range (Vdd) Vdd -0.5 to 4
Latch-up Tolerance JESD78 Compliant
Mechanical Shock Resistance F/F Mil 883, Method 2002 TBD g
Mechanical Vibration Resistance F/F Mil 883, Method 2005 TBD g
2012 SMD Junction Temperature TBD
Storage Temperature -65°C to 150°C
Thermal Consideration
Package
JA, 4 Layer Board
(°C/W)
JA, 2 Layer Board
(°C/W)
JC, Bottom
(°C/W)
2012 SMD TBD
Ultra-Low
Power
PLL
Sustaining
Amp
Regulators Vdd
GND CLK Out
Prog
Divider
NC
MEMS Resonator
Prog
Control
Trim
Ultra-Low
Power Driver
SMD Package (Top View)
NC CLK Out
Vdd
GND
2
4
31
The Smart Timing Choice
The Smart Timing Choice
SiT1533
Ultra-Low Power 32.768 kHz XTAL Replacement in 2.0 x 1.2 mm SMD
Rev. 0.77 Page 3 of 7 www.sitime.com
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.
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 1.2mm2 CSP.
Figure 2. SiT1533 Footprint Compatibility with
Quartz XTAL Footprint (5)
Frequency Stability
The SiT1533 is factory calibrated (trimmed) to guarantee
frequency stability to be less than 20 PPM at room temper-
ature and less than 100 PPM over the full -40°C to +85°C
temperature 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. Contact
SiTime for applications that require a wider supply voltage
range >3.63V, or lower operating frequency below 32 kHz.
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.
Output Voltage
For low-power applications that drive directly into a chip-set’s
XTAL input, the reduced swing output is ideal. SiTime’s unique
NanoDrive™, factory-programmable output stage is optimized
for low voltage swing to minimize power and maintain compat-
ibility with the downstream oscillator input (X IN pin). The
SiT1533 output swing is customer specific and factory
programmed between 250 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 500 mV and 1.2V in 100 mV
increments. Similarly, VOL programming range is between 350
mV and 800 mV. For DC-biased NanoDrive™ output configu-
ration, the minimum VOL is limited to 350mV. For example,
1.1V VOH and 400mV VOL is acceptable, but 1.0V VOH and
350mV VOL is not acceptable. Contact SiTime for
programming support.
Quartz SiTime
X OUT
X IN
Connect to
X OUT or NC
Clock Out
Connect to X IN
GND
VDD
Top ViewTop View
1
2
4
3
Note:
5. 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.
The Smart Timing Choice
The Smart Timing Choice
SiT1533
Ultra-Low Power 32.768 kHz XTAL Replacement in 2.0 x 1.2 mm SMD
Rev. 0.77 Page 4 of 7 www.sitime.com
Calculating Load Current
No Load Supply Current
When calculating no-load power for the SiT1533, the core and
output driver components need to be added. Since the output
voltage swing can be programmed for reduced swing between
250 mV and 800 mV for ultra-low power applications, 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:
Total Supply Current (no load) = Idd Core + (65nA/V)(Voutpp)
Example 1: Full-swing LVCMOS
• Vdd = 1.8V
• Idd Core = 900nA (typ)
•Vout
pp = 1.8V
Supply Current = 900nA + (65nA/V)(1.8V) = 1047nA
Example 2: NanoDrive™ Reduced Swing
• Vdd = 1.8V
• Idd Core = 900nA (typ)
•Vout
pp (Programmable) = VOH – VOL = 1.1V - 0.6V = 500mV
Supply Current = 900nA + (65nA/V)(0.5V) = 832nA
Total Supply Current with Load
To calculate the total supply current, including the load, follow
the equation listed below. Note the 30% reduction in power
with NanoDrive™.
Total Current = Idd Core + Idd Output Driver (65nA/V*Vout
pp
)
+ Load Current (C*V*F)
Example 1: Full-swing LVCMOS
• Vdd = 1.8V
• Idd Core = 900nA
• Load Capacitance = 10pF
• Idd Output Driver: (65nA/V)(1.8V) = 117nA
• Load Current: (10pF)(1.8V)(32.768kHz) = 590nA
• Total Current = 900nA+117nA+590nA = 1.6µA
Example 2: NanoDrive™ Reduced Swing
• Vdd = 1.8V
• Idd Core = 900nA
• Load Capacitance = 10pF
• Vout
pp
(Programmable): VOH – VOL = 1.1V - 0.6V = 500mV
• Idd Output Driver: (65nA/V)(0.5V) = 33nA
• Load Current: (10pF)(0.5V)(32.768kHz) = 164nA
• Total Current = 900nA + 33nA + 164nA = 1.1µA
The Smart Timing Choice
The Smart Timing Choice
SiT1533
Ultra-Low Power 32.768 kHz XTAL Replacement in 2.0 x 1.2 mm SMD
Rev. 0.77 Page 5 of 7 www.sitime.com
Dimensions and Patterns
Package Size – Dimensions (Unit: mm) Recommended Land Pattern (Unit: mm)
2.0 x 1.2 mm SMD SiTime Only SPL
XTAL Compatible SPL
#1
#2
#3
#4
#3 #1
#4
#2
The Smart Timing Choice
The Smart Timing Choice
SiT1533
Ultra-Low Power 32.768 kHz XTAL Replacement in 2.0 x 1.2 mm SMD
Rev. 0.77 Page 6 of 7 www.sitime.com
Ordering Information
Part number characters in blue represent the customer specific options. The other characters in the part number are fixed. Here
are guidelines to select the correct output voltage.
1) For XTAL replacement applications that will keep the chipset oscillator enabled, configure the NanoDrive™ output for a
swing similar to the XTAL, approximately 250mV.
→ SiT1533AI-H4-AA2-32.768
2) For XTAL replacement applications that will disable the chipset oscillator, configure the output with one of the following:
• For VDD = 1.8V: SiT1533AI-H4-D14-32.768
• For VDD > 1.8V: SiT1533AI-H4-DCC-32.768
The following examples illustrate how to select the appropriate temp range and output voltage requirements:
Example 1: SiT1533AI-H4-D14-32.768
• Industrial temp & corresponding 100 PPM frequency stability. Note, 100 PPM is only available for the industrial temp range,
and 75 PPM is only available for the commercial temp range.
• Output swing requirements:
a) “D” = DC-coupled receiver
b) “1” = VOH = 1.1V
c) “4” = VOL = 0.4V
Example 2: SiT1533AC-H5-AA2-32.768
• Commercial temp & corresponding 75 PPM frequency stability. Note, 100 PPM is only available for the industrial temp range,
and 75 PPM is only available for the commercial temp range.
• Output swing requirements:
a) “A” = AC-coupled receiver
b) “A” = AC-coupled receiver
c) “2” = 250mV swing
SiT1533AI-H4-D14-32.768S
Output Clock Frequency
32.768 kHz
Part Family
“SiT1533”
Revision Letter
“A”: is the revision
Temperature Range
“I”: Industrial, -40 to 85ºC DC-coupled Output VOL or
AC Swing
“2”: 250mV
“3”: 300mV
“4”: 400mV
“5”: 500mV
“6”: 600mV
“7”: 700mV
“8”: 800mV
“C”: rail-to-rail LVCMOS
Packaging
“C”: Commercial, -10 to 70ºC
Package Size
“S”: 8 mm Tape & Reel, 10ku reel
2.0 mm x 1.2 mm SMD
“D”: 8 mm Tape & Reel, 3ku reel
“E”: 8 mm Tape & Reel, 1ku reel
Frequency Stability
“4”: ±100 PPM (-40 to 85ºC only)
“5”: ±75 PPM (-10 to 70ºC only)
AC- or DC-coupled
“A”: AC-coupled Signal Path Rx
“D”: DC-coupled Signal Path or
Rail-to-Rail LVCMOS
DC-coupled Output VOH
“5”: 500mV
“6”: 600mV
“7”: 700mV
“8”: 800mV
“9”: 900mV
“0”: 1.00V
“1”: 1.10V
“2”: 1.20V
“A”: AC-coupled Receiver
“C”: rail-to-rail LVCMOS
Blank for Bulk
Rev. 0.77 Page 7 of 7 www.sitime.com
© SiTime Corporation 2013. The information contained herein is subject to change at any time without notice. SiTime assumes no responsibility or liability for any loss, damage or defect of a
Product which is caused in whole or in part by (i) use of any circuitry other than circuitry embodied in a SiTime product, (ii) misuse or abuse including static discharge, neglect or accident, (iii)
unauthorized modification or repairs which have been soldered or altered during assembly and are not capable of being tested by SiTime under its normal test conditions, or (iv) improper
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The Smart Timing Choice
The Smart Timing Choice
Ultra-Low Power 32.768 kHz XTAL Replacement in 2.0 x 1.2 mm SMD
SiT1533
