ZL30263LDF1 vs LMK04806BISQ/NOPB
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| Category | Clock/Timing - Clock Generators, PLLs, Frequency Synthesizers | Clock/Timing - Clock Generators, PLLs, Frequency Synthesizers |
| Manufacturer | Microchip Technology | National Semiconductor |
| Description | IC CLOCK MULTI/FREQ SYNTH 56QFN | LMK04806 LOW NOISE CLOCK JITTER |
| Package | Tape & Reel (TR) | Bulk |
| Series | - | PLLatinum™ |
| Type | Clock Multiplier, Frequency Synthesizer | Jitter Cleaner |
| Voltage - Supply | 1.71V ~ 3.465V | 3.15V ~ 3.45V |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Package / Case | 56-VFQFN Exposed Pad | 64-WFQFN Exposed Pad |
| Supplier Device Package | 56-QFN (8x8) | 64-WQFN (9x9) |
| Output | CMOS, HCSL, HSTL, LVDS, LVPECL | LVCMOS, LVDS, LVPECL |
| Frequency - Max | 1.045GHz | 1.536GHz |
| Number of Circuits | 1 | 1 |
| Input | CMOS, Crystal | LVCMOS, LVDS, LVPECL |
| PLL | Yes with Bypass | Yes |
| Ratio - Input:Output | 4:10 | 2:14 |
| Differential - Input:Output | Yes/Yes | Yes/Yes |
| Divider/Multiplier | Yes/No | Yes/No |
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1. What is a PLL frequency synthesizer?
A PLL frequency synthesizer is a device that generates multiple output frequencies using phase-locked loop technology. Its core function is to generate different multiples of frequencies from a single reference frequency. This method is widely used in radio frequency (RF) communication systems, especially in generating local oscillator (LO) signals for up-conversion and down-conversion of RF signals.
The working principle of a PLL frequency synthesizer is based on phase-locked loop technology, which includes key components such as phase/frequency detector (PFD), loop filter, and voltage-controlled oscillator (VCO). -
2. Which is better, direct digital synthesis or PLL?
Direct digital synthesis (DDS) and PLL each have their own advantages and disadvantages. Choosing which one is better depends on the specific application requirements. DDS performs well in frequency switching speed and high resolution, while PLL has more advantages in phase noise and spurious performance.
The advantages of DDS include:
High frequency switching speed: DDS works in the digital domain. Once the frequency control word is updated, the output frequency changes accordingly, and the frequency hopping rate is high.
High resolution: Due to the large width of the frequency control word (such as 48bit or higher), the frequency resolution is high.
Flexibility: DDS can generate any desired waveform and initial phase, suitable for applications requiring a wide range of scenarios.
PLL advantages include:
Low phase noise: PLL excels in low phase noise and low spurious performance, suitable for applications requiring high stable frequency.
Wide frequency range: The upper limit of the PLL output frequency depends on the upper limit of the VCO, which can support a wider frequency range.
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3. What are frequency synthesizers used for?
The main purpose of frequency synthesizers is to provide specific frequency signals for radio and communication systems. It is an important component of modern electronic systems and is widely used in communication, radar, navigation and other equipment.
Frequency synthesizers generate a large number of discrete frequencies with the same stability and accuracy from one or more reference signal sources with high frequency stability and accuracy through linear operations in the frequency domain. Specifically, frequency synthesizers use techniques such as frequency multiplication, frequency division, and mixing to obtain discrete frequency signals with the same stability as the reference signal. -
4. What are the three types of frequency synthesizers?
There are three main types of frequency synthesizers: direct analog frequency synthesis, indirect frequency synthesis, and direct digital frequency synthesis.
Direct analog frequency synthesis: This method uses one or more different crystal oscillators as reference signal sources to directly generate many discrete frequency output signals through frequency multiplication, frequency division, mixing, etc. The advantages of direct analog frequency synthesis are high long-term and short-term frequency stability and fast frequency conversion speed, but it is difficult to debug and difficult to suppress spurious signals.
Indirect frequency synthesis: also known as phase-locked loop frequency synthesis technology (PLL), using one or several reference frequency sources, through harmonic generator mixing and frequency division, etc. to generate a large number of harmonics or combined frequencies, and then use a phase-locked loop to lock the frequency of the voltage-controlled oscillator to a certain harmonic or combined frequency. The advantages of indirect frequency synthesis are low cost and the ability to synthesize any frequency, but slow response, mainly used in civilian equipment.
Direct digital frequency synthesis: This method performs frequency synthesis based on the concept of phase, using digital sampling and storage technology, with the advantages of precise phase and frequency resolution, fast conversion time, etc. The key components of direct digital frequency synthesis include digital-to-analog converters, phase accumulators, and memories, etc., which store the required waveform version in digital format and create signals.
