Ordering Information .................................................................................................................................................................... 2
User Programming Interface ..................................................................................................................................... 18
Start-up output frequency and signaling types ........................................................................................................... 18
Any-frequency function ............................................................................................................................................. 19
C/SPI Control Registers...................................................................................................................................................... 28
9 I
Register Address: 0x00. DCO Frequency Control Least Significant Word (LSW) .................................................... 28
Register Address: 0x01. OE Control, DCO Frequency Control Most Significant Word (MSW) ................................. 29
Register Address: 0x02. DCO PULL RANGE CONTROL ........................................................................................ 29
Register Address: 0x03. Frac-N PLL Feedback Divider Integer Value and Frac-N PLL Feedback Divider Fraction
Value MSW ............................................................................................................................................................... 30
Register Address: 0x05. Forward Divider, Driver Control ......................................................................................... 30
Register Address: 0x06. Driver Divider, Driver Control ............................................................................................. 31
2
C Operation ........................................................................................................................................................................ 32
10 I
I
2
C protocol ............................................................................................................................................................... 32
I
2
C Timing Specification ............................................................................................................................................ 35
I
2
C Device Address Modes ....................................................................................................................................... 36
Dimensions and Patterns ........................................................................................................................................................... 43
Additional Information ................................................................................................................................................................ 44
Revision History ......................................................................................................................................................................... 45
Rev 1.01
Page 3 of 45
www.sitime.com
SiT3521
1 to 340 MHz Elite Platform I2C/SPI Programmable Oscillator
1 Electrical Characteristics
All Min and Max limits in the Electrical Characteristics tables are specified over temperature and rated operating voltage with
standard output terminations shown in the termination diagrams. Typical values are at 25°C and nominal supply voltage.
Table 1. Electrical Characteristics – Common to LVPECL, LVDS and HCSL
Parameter
Output Frequency Range
Symbol
f
Min.
1
Typ.
–
–
–
–
–
±1
–
–
–
Max.
340
Unit
MHz
Condition
Factory or user programmable, accurate to 6 decimal places
Frequency Range
Frequency Stability
Frequency Stability
F_stab
-10
-20
-25
-50
First Year Aging
F_1y
–
+10
+20
+25
+50
–
ppm
ppm
ppm
ppm
ppm
°C
°C
°C
1
st
-year aging at 25°C
Inclusive of initial tolerance, operating temperature, rated
power supply voltage and load variations.
Temperature Range
Operating Temperature Range
T_use
-20
-40
-40
+70
+85
+105
Supply Voltage
Supply Voltage
Vdd
2.97
2.7
2.52
2.25
3.3
3.0
2.8
2.5
–
–
100
–
–
–
3.63
3.3
3.08
2.75
–
30%
–
V
V
V
V
Extended Commercial
Industrial
Extended Industrial. Available only for I
2
C operation, not SPI.
Input Characteristics – OE Pin
Input Voltage High
Input Voltage Low
Input Pull-up Impedance
VIH
VIL
Z_in
70%
–
–
Vdd
Vdd
kΩ
OE pin
OE pin
OE pin, logic high or logic low
Output Characteristics
Duty Cycle
DC
45
–
–
55
%
Startup and Output Enable/Disable Timing
Start-up Time
Output Enable/Disable Time –
Hardware control via OE pin
Output Enable/Disable Time –
Software control via I
2
C/SPI
T_start
T_oe_hw
3.0
3.8
ms
µs
Measured from the time Vdd reaches its rated minimum value
Measured from the time OE pin reaches rated VIH and VIL to
the time clock pins reach 90% of swing and high-Z.
See
Figure 9
and
Figure 10
Measured from the time the last byte of command is
transmitted via I
2
C/SPI (reg1) to the time clock pins reach 90%
of swing and high-Z. See
Figure 30
and
Figure 31
T_oe_sw
–
–
6.5
µs
Rev 1.01
Page 4 of 45
www.sitime.com
SiT3521
1 to 340 MHz Elite Platform I2C/SPI Programmable Oscillator
Table 2. Electrical Characteristics – LVPECL Specific
Parameter
Symbol
Min.
Typ.
Max.
Unit
Condition
Current Consumption
Current Consumption
OE Disable Supply Current
Output Disable Leakage Current
Maximum Output Current
Idd
I_OE
I_leak
I_driver
–
–
–
–
–
–
0.15
–
89
58
–
32
mA
mA
A
mA
Excluding Load Termination Current, Vdd = 3.3 V or 2.5 V
OE = Low
OE = Low
Maximum average current drawn from OUT+ or OUT-
Output Characteristics
Output High Voltage
Output Low Voltage
Output Differential Voltage Swing
Rise/Fall Time
VOH
VOL
V_Swing
Tr, Tf
Vdd - 1.1V
Vdd - 1.9V
1.2
–
–
–
1.6
225
Vdd - 0.7V
Vdd - 1.5V
2.0
290
Jitter
RMS Phase Jitter (random) –
DCO Mode Only
T_phj
–
–
RMS Phase Jitter (random) –
Any-frequency Mode Only
T_phj
–
–
RMS Period Jitter
[3]
Note:
3. Measured according to JESD65B.
T_jitt
–
0.225
0.1
0.225
0.11
1
0.340
0.14
0.340
0.15
1.6
ps
ps
ps
ps
ps
f = 156.25 MHz, Integration bandwidth = 12 kHz to 20 MHz,
all Vdd levels
f = 156.25, IEEE802.3-2005 10 GbE jitter mask integration
bandwidth = 1.875 MHz to 20 MHz, all Vdd levels
f = 156.25 MHz, Integration bandwidth = 12 kHz to 20 MHz,
all Vdd levels
f = 156.25, IEEE802.3-2005 10 GbE jitter mask integration
bandwidth = 1.875 MHz to 20 MHz, all Vdd levels
f = 100, 156.25 or 212.5 MHz, Vdd = 3.3 V or 2.5 V
V
V
V
ps
See
Figure 5
See
Figure 5
See
Figure 6
20% to 80%, see
Figure 6
Table 3. Electrical Characteristics – LVDS Specific
Parameter
Symbol
Min.
Typ.
Max.
Unit
Condition
Current Consumption
Current Consumption
OE Disable Supply Current
Output Disable Leakage Current
Idd
I_OE
I_leak
–
–
–
–
–
0.15
80
61
–
mA
mA
A
Excluding Load Termination Current, Vdd = 3.3 V or 2.5 V
OE = Low
OE = Low
Output Characteristics
Differential Output Voltage
Delta VOD
Offset Voltage
Delta VOS
Rise/Fall Time
VOD
ΔVOD
VOS
ΔVOS
Tr, Tf
250
–
1.125
–
–
–
–
–
–
400
455
50
1.375
50
470
Jitter
RMS Phase Jitter (random) –
DCO Mode Only
T_phj
–
–
RMS Phase Jitter (random) –
Any-frequency Mode Only
T_phj
–
–
RMS Period Jitter
[4]
Note:
4. Measured according to JESD65B.
T_jitt
–
0.21
0.1
0.21
0.1
1
0.275
0.12
0.367
0.12
1.6
ps
ps
ps
ps
ps
f = 156.25 MHz, Integration bandwidth = 12 kHz to 20 MHz,
all Vdd levels
f = 156.25, IEEE802.3-2005 10 GbE jitter mask integration
bandwidth = 1.875 MHz to 20 MHz, all Vdd levels
f = 156.25 MHz, Integration bandwidth = 12 kHz to 20 MHz,
all Vdd levels
f = 156.25, IEEE802.3-2005 10 GbE jitter mask integration
bandwidth = 1.875 MHz to 20 MHz, all Vdd levels
f = 100, 156.25 or 212.5 MHz, Vdd = 3.3 V or 2.5 V
mV
mV
V
mV
ps
f = 156.25MHz See
Figure 7
See
Figure 7
See
Figure 7
See
Figure 7
Measured with 2 pF capacitive loading to GND, 20% to 80%,
#inI am using 2 8421 coding switches and stc15w201s to make a 9.9 second delay switch. The following program does not work properly. Please give me your advice.
#includereg52.h
sbit timeup = P1^4; //D...
[font=微软雅黑][size=3]I went to Miaofeng Mountain last Saturday. It was 22 kilometers from the bottom of the mountain to the top. I walked up. My legs are still hurting today :Sweat: It seems that I need...
$HandlerLabel Sub sp,sp ,#4; stmfd sp!,{r0}; ldr r0,=$HandleLabel ldr r0,[r0]; str r0 ,{sp ,#4}; ldmfd sp!,{r0,pc} This is a piece of code in the arm interrupt. There are a few places that I don't qui...
[size=24px]I posted twice about transferring my own development version, and you deleted them. At least you should give me a reason!!! 1. This is a non-technical area, and there is no top information ...
In recent years, with the increasing demand for manufacturing and automated production management, industrial barcode scanners have gradually become an indispensable part of the industrial manufact...[Details]
In recent years, the government has increasingly supported electric vehicles, and the number of electric vehicles has increased. Observant drivers will notice that there are many more green license...[Details]
Multi-touch mobile phone
Multi-touch is a system that can respond to multiple touches on the screen at the same time. Multi-touch phones are divided into capacitive and resistive types. Capaci...[Details]
1 Introduction
In the mid-1960s, American scientist Maas conducted extensive experimental research on the charging process of open-cell batteries and proposed an acceptable charging curve for ...[Details]
Recently, South Korean robotics giant WIRobotics launched its first general-purpose humanoid robot, ALLEX, at the Robotics Innovation Center (RIH) at the Korea University of Science and Technology....[Details]
One of the most core components of electric vehicles is the motor. The power supply provides electrical energy to the motor, which converts this electrical energy into mechanical energy, which in t...[Details]
The MCX E series is the most reliability- and safety-focused series in NXP's extensive MCX product portfolio.
With the launch of this series, NXP has further enriched its 5V-compatible MCU pr...[Details]
China, August 21, 2025 – STMicroelectronics (NYSE: STM), a world-leading semiconductor company serving a wide range of electronics applications, has published its IFRS 2025 semi-annual financial re...[Details]
In the period after the switching power supply achieved the "20 kHz" revolution in the 1970s, although improvements and enhancements were made in circuit technology, the development level of the se...[Details]
Previously, Positive Motion Technology shared with you the firmware upgrade of motion controller, ZBasic program development, ZPLC program development, communication with touch screen and input/out...[Details]
MQTT Ethernet I/O modules primarily collect I/O port information and transmit data over the network. In addition to being a TCP server, Ethernet I/O modules can also function as TCP clients. Furthe...[Details]
There are more and more electric vehicles. Recently, I have heard some news about electric vehicles performing poorly in winter. I would like to briefly introduce whether heat pump technology is mo...[Details]
The driving mode is not unfamiliar to vehicles. According to the driving mode of the vehicle, there are front-wheel drive, rear-wheel drive and even four-wheel drive. Four-wheel drive is a major se...[Details]
For today's new energy vehicles, they have different configurations from fuel vehicles, and some configurations have also become a selling point for manufacturers. Compared with traditional vehicle...[Details]
introduction
In recent years, multi-touch has emerged as a new alternative to traditional human-computer interaction. It eliminates the need for keyboards and mice, enabling simultaneous inter...[Details]
51mcu
京公网安备 11010802033920号
EEWORLD
