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It is recommended connecting the Shutdown/OE pin to VDD or GND to be on the safe side. However, a 5ms pulse for Shutdown pin should not be a problem. The shutdown signal should propagate in nano seconds, the PLL and outputs should be turned off in micro seconds and the oscillator should be off in milli seconds for the CY22392.
Show LessPhase Jitter is used to characterize crystal oscillators and other devices where random (Gaussian distribution) jitter dominates. To obtain optimal performance, designers attempt to minimize phase jitter for each component in the system. As phase jitter accumulates in a high-speed system, several potential problems can arise. If the reference clock suffers from excessive phase jitter, the BER for a communications link can increase, or the dynamic range of an ADC or DAC can be limited with increased SNR. By limiting the clock phase jitter as much as possible, these and other potential problems can be avoided.
Each component in a system clock tree adds phase jitter to the clock signal. When selecting distribution components, designers should attempt to use components with the lowest additive phase jitter to give themselves the most noise margin.
Show LessTUS9090 supports DVB-T and DVB-H. This tuner can provide 4 different bandwidths, which are 5,6,7,8MHz respectively. The tuner adopts a direct conversion receiver structure. It includes a complex filter to eliminate out-band noises. Is this bandwidth of the complex filter configurable?
Thanks a lot! Show Less
The noise floor of the CY2304NZ is lower than any reference source we have, so phase noise must be measured in a two-port (residual) manner, where the E5500 measures the phase noise of the difference between the input and output signals. Above 1 MHz offset, the curve increases because the delay of the two paths was not fully matched. In reality it is most likely flat.
Attached is CY2304NZ Residual Phase Noise at 80MHz
Show LessGanging outputs together to improve output-output skew or drive larger loads is the option usually considered. No problems can be expected with ganging from a design point of view of a device. As an alternate solution, one might try to use a high-drive version of the part first instead of ganging multiple outputs together. The high-drive version will be able to drive a larger load than the standard drive part.
The High drive versions are identified with an alphabet “H” in Cypress devices. As an example, CY2305CSXC-1H is a High drive version of its standard drive counterpart CY2305CSXC-1.
Show LessWhen the reference clocks phase changes, there will be a noticeable change to the output frequency as it adjusts lock to the new clock. The output will also experience high cycle-to-cycle jitter for a short time. The lock time, however, is much less than the power-on lock time.
Look at the attached document that shows how the CY22381 responds when the reference clock has a 180 degree phase change.
Normally additive jitter is not specified for the parts that are just fanout buffers with no PLL inside. Such a non zero delay buffer like CY2304NZ would not introduce too much additional jitter since they are just buffers (i.e. not that many transistors, simple circuit, etc.). Typical RMS Jitter that can be added to the output is approximately 10 ps for CY2304NZ and Period jitter will be less 10 ps for the CY2304NZ.
Attached are the measurements at different frequencies for a fair idea. In the document attached, kindly note that when you apply the signal from the used Agilent 8133A pulse generator (input), it has the jitter value as shown in Table 2. So Table 2 shows the jitter measured on the output of the Agilent 8133A pulse generator that is applied as the input to the CY2304NZ. The resulting output jitter is shown in Table 1 corresponding to the frequency and the type of jitter measured. So you can clearly observe that the jitter at the output is almost equal to the input. There is not much additive jitter from the buffer. So you need to have a clean source at the input.
Show LessThis is not recommended way of operation and is not intended either. However, if someone wants to know if the input reference clock is suddenly stopped (0MHz), how many cycles of CLKOUT will keep as the former output clock, then the output changes to unlock, it was measured to see how the CY2305 behaves under nominal conditions (25C and 3.3V).
The output usually holds the original frequency for only a few cycles. Generally you cannot expect more than 2 or 3 cycles at the normal frequency. It then drops towards a lower frequency. For example,
100 MHz drops towards 80 MHz, stops after ~120 cycles
80 MHz drops towards 70 MHz, stops after ~120 cycles
60 MHz drops towards 50 MHz, stops after ~90 cycles
40 MHz drops towards 30 MHz, stops after ~50 cycles
20 MHz drops towards 14 MHz, stops after ~25 cycles
10 MHz goes very quickly towards 5 MHz, stops after ~10 cycles
In all cases, the output clock stops in about 1.5 to 2 microseconds.
If you look at the jedec file for CY22150, although the format may not be obvious, it's also not complicated. Starting with the first block:
L00064
0101101000000001000000000000000010000100
0000011000001000100010001000000011101100
00110000000000000000000000000000*
In the first line, 64 is the (decimal) bit address of the first bit. Divide this value by 8 to get the byte address. So this string of bits begins at register address 8. Divide the bits into groups of 8, representing byte values. The bits in each byte are ordered MSB to LSB (left to right), so they are shifted into the I2C port in exactly the order shown. White space (spaces and carriage returns) are ignored. The above data is shown below as a series of bytes.
I2C
address
08H 01011010
09H 00000001
0AH 00000000
0BH 00000000
0CH 10000100
0DH 00000110
0EH 00001000
0FH 10001000
10H 10000000
11H 11101100
12H 00110000
13H 00000000
14H 00000000
15H 00000000
There is a gap of unused addresses, then the next block of data starts at L00512.
512 / 8 = 64 (decimal) = 40H
Similar breakdown applies for further addresses. So the bits in groups of 8 following "L00512" in the JEDEC file start at 40h and go to FFh. After L00512 shift in 40h to 47h. Settings after that do not matter.
The divider bank design in the CY22150 does not guarantee any phase relationship except for the conditions mentioned in the datasheet on page 8. On power-up, the dividers start from an unknown state which may change from one power-up cycle to another. Phase relationship is maintained only when the output clocks are coming from the same divider. The output dividers are not synchronized to each other and can power up in random states. There is NO synchronization circuitry included for different dividers in both CY22150.
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