MK2049-45ASI - 51.84MHz Dual-PLL Clock Synth | Renesas
料号： MK2049-45ASI ✓ 量产中MK2049-45ASI 概述
A phase-locked-loop clock synthesizer belongs to the clock and timing IC hierarchy, where it sits below clock-generation and frequency-synthesis functions. It locks an internal oscillator to a reference clock and then generates or divides reference-derived frequencies. Unlike a free-running oscillator, a PLL-based device can transfer frequency stability from an external reference while allowing output frequency synthesis, programmable division, and jitter attenuation.
The MK2049-45ASI contains two PLL functions. According to the Renesas MK2049-45 datasheet, the first PLL is VCXO-based and uses a pullable crystal to track signal wander and attenuate input jitter. The second PLL supports frequency synthesis. A maximum output frequency of 51.84 MHz and a 1:3 input-to-output ratio identify the device as a communications-clock generation solution rather than a general-purpose timer.
The device accepts a clock reference and produces a clock output without differential signaling. Its architecture is intended to support communications equipment that needs a stable, derived clock while limiting reference jitter. The 3.3 V supply designation also places the device in systems designed around low-voltage digital clock trees, provided the complete power, input, output, and decoupling requirements are followed from the manufacturer datasheet.
Typical applications include communication line-card clocking, telecom backplane clock distribution, network-interface clock synthesis, and other systems requiring a PLL-derived communications reference. The maximum 51.84 MHz output makes it particularly relevant to designs operating below that frequency while using a stable external reference and controlled division ratio.
When designing a board around the MK2049-45ASI, use the manufacturer pin-description table and recommended external-component values before finalizing the layout. Pay particular attention to clock-input routing, pullable-crystal implementation, output loading, supply decoupling, and unused-pin handling, because incorrect clock topology can undermine otherwise correct PLL operation.
This product summary organizes the device architecture, package information, verified drop-in candidates, parameter comparisons, and practical clock-design guidance into a format that helps engineers evaluate the MK2049-45ASI before beginning a communications-clock schematic.
直接替换替代料： MK2049-45ASI ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： MK2049-45ASI （相同外形与封装尺寸） ——差异在于 Device Type, Package.
MK2049-45ASITR
✅ 直接替换📋 参考替代料（不在目录中）
MK2049-45SI
✅ 直接替换联系询价
查看数据手册 →MK2049-45A
✅ 直接替换📋 参考替代料（不在目录中）
MK2049-45ASI 规格参数
| Device Type | PLL Clock Synthesizer |
| Architecture | Dual Phase-Locked Loop |
| PLL | Yes |
| Input Signal | Clock |
| Output Signal | Clock |
| Maximum Frequency | 51.84 MHz |
| Number of Circuits | 1 |
| Input-to-Output Ratio | 1:3 |
| Differential Input | No |
| Differential Output | No |
| 电源电压 | 3.3 V |
| 封装 | 20-pin SOIC |
| Package Width | 0.295 inch (7.50 mm) |
| 安装类型 | Surface Mount |
| VCXO-Based PLL | Yes |
MK2049-45ASI 0.295 inch (7.50 mm) 引脚配置指南
MK2049-45ASI（0.295 inch (7.50 mm) 封装）的引脚配置。 引脚编号、功能和连接图在制造商数据手册中定义。请参阅该手册以了解确切的封装尺寸和焊接指南。
暂无详细引脚数据： MK2049-45ASI.
请参阅 数据手册 以查看完整引脚配置。
典型应用
MK2049-45ASI 适用于 6 应用s: Telecom Line-Card Clocking, Network-Interface Clock Generation, Jitter-Attenuated Clock Reference, Communications Backplane Clock Distribution, Telecom Interface Module Timing, Low-Voltage Digital Clock Tree.
Telecom Line-Card Clocking
The MK2049-45ASI fits telecom line-card designs that require a reference-derived communications clock. Its dual phase-locked-loop architecture supports frequency synthesis and jitter attenuation, while the 51.84 MHz maximum frequency accommodates clocks below that ceiling. The VCXO-based first PLL can track signal wander using a pullable crystal, making the device appropriate for clock trees sensitive to phase disturbances. Design the reference path and external loop network from the manufacturer application guidance, and verify all timing margins against the actual system reference frequency.
Network-Interface Clock Generation
The MK2049-45ASI can generate a stable interface clock from an external reference in network-interface and communications equipment. Its 1:3 stated input-to-output relationship provides a defined basis for clock-tree planning, while the 51.84 MHz maximum output covers common sub-51.84 MHz communications-clock requirements. The second PLL performs frequency synthesis and the VCXO-based loop attenuates reference jitter. Confirm whether the required frequency ratio, output count, and loop bandwidth are supported by the final device configuration before schematic capture.
Jitter-Attenuated Clock Reference
Applications requiring cleaner reference-derived timing can use the MK2049-45ASI to combine jitter attenuation with frequency synthesis. The first phase-locked loop is VCXO-based and uses a pullable crystal to track signal wander, while the second loop generates the required output clock. This architecture is useful when an upstream reference contains wander or phase variation that would otherwise appear at the output. Actual jitter performance depends on the reference source, crystal selection, loop settings, supply quality, and PCB implementation, all of which should be validated with the manufacturer guidance.
Communications Backplane Clock Distribution
A communications backplane can use the MK2049-45ASI as a local clock-generation element before distribution through board-level clock buffers. The device supplies a single-ended clock output at up to 51.84 MHz and derives it through PLL architecture rather than free-running logic. That makes it useful when the backplane requires a disciplined clock related to an upstream reference. Keep sensitive traces short, observe return paths, and separate the regulator, reference, crystal, and clock-routing regions to preserve signal integrity from the oscillator through the distribution stage.
Telecom Interface Module Timing
The MK2049-45ASI is suitable for timing generation inside telecom interface modules that accept a reference clock and need a stable derived output. Its 3.3 V communications-clock supply designation and 20-pin SOIC package align with compact line-card and interface hardware. Use the PLL outputs to support endpoint circuits requiring frequency translation or division. Before committing the design, confirm the complete input frequency range, configuration method, output-drive capability, and loop bandwidth because those details determine whether a 51.84 MHz maximum rating is adequate for the intended data rate.
Low-Voltage Digital Clock Tree
The MK2049-45ASI can serve as the synthesis element in a low-voltage digital clock tree when the system operates from a 3.3 V supply and requires a clock below 51.84 MHz. PLL-based generation allows multiple sections of the system to use a common reference rather than independent oscillators, improving synchronization and simplifying architecture. The single-ended input and output also support conventional board routing. Decouple the supply locally, keep the reference path away from noisy switching nodes, and validate the final rise time, load, and output-jitter performance at the receiver.
工程参考数据： MK2049-45ASI ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | MK2049-45ASITR | MK2049-45SI | MK2049-45A |
|---|---|---|---|---|
| Package | 20-pin SOIC | 20-pin SOIC - same | 20-pin SOIC - same | 20-pin SOIC - same |
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Device Type | PLL Clock Synthesizer | Clock Generator / PLL | Clock Generator / PLL | Dual Phase-Locked Loop |
| Maximum Frequency | 51.84 MHz | 51.84 MHz | 51.84 MHz | 51.84 MHz |
| Supply Voltage | 3.3 V | 3.3 V | 3.3 V | 3.3 V |
| Architecture | Dual Phase-Locked Loop | Dual Phase-Locked Loop | Dual Phase-Locked Loop | Dual Phase-Locked Loop |
| Input-to-Output Ratio | 1:3 | 1:3 | 1:3 | 1:3 |
| Differential Input/Output | No/No | No/No | No/No | No/No |
关键差异点
- Direct same-package ordering alternative （对比 MK2049-45ASITR)
- Reference-derived dual-loop architecture （对比 MK2049-45SI)
- Communications-focused clock synthesis （对比 MK2049-45A)
设计说明
Place the 3.3 V supply bypass capacitor close to the device supply pins and provide a continuous ground reference beneath the SOIC. Route the clock input and output away from switching nodes and high-current return paths. Because the architecture includes a VCXO-based loop, a pullable crystal and its associated loop components require short, quiet traces; follow the manufacturer reference layout and component-selection guidance before finalizing placement.
Treat the reference, oscillator, and synthesized-clock paths as timing-sensitive nets. Use a controlled-impedance board where the clock frequency or edge rate makes transmission-line behavior relevant, keep the clock away from parallel high-speed data, and confirm the output waveform at the far-end load. The published 51.84 MHz maximum frequency does not by itself specify acceptable rise time, jitter, or loading for a specific board.
Do not assume that every suffix with the MK2049-45 family name has identical temperature, qualification, or ordering characteristics. Compare the complete ordering information, supply limits, clock frequencies, and pin configuration against the exact replacement part. For a drop-in substitution, verify that the existing pullable-crystal network, reference amplitude, output loading, and decoupling remain unchanged.
合规信息
The Renesas datasheet and product page are the controlling sources for device functionality, but the retrieved material does not state the required compliance conclusions.
