SY87729LHG - 365MHz Fractional Clock Synthesizer | Microchip
Артикул: SY87729LHG ✗ Снят с производстваSY87729LHG Обзор
A fractional-N synthesizer is a clock-and-timing IC that uses a phase-locked loop to create an output frequency related to a reference frequency while supporting fractional division. Within the clock-and-timing hierarchy, the SY87729LHG belongs to the PLL-based synthesizer category. This positioning distinguishes it from simple oscillators and fixed-ratio clock buffers: the device is intended to derive precise communications-clock frequencies from an external reference and then deliver a differential PECL output.
The verified product record identifies the SY87729LHG as a monolithic fractional synthesizer with PLL capability, one output circuit, a 1:1 input-to-output ratio, and differential input and output operation. Its maximum frequency is listed as 365 MHz. The part is marked obsolete in the supplied datasheet-derived listing, so it should be treated as a legacy clock source for maintenance, replication, and redesign analysis rather than a recommended choice for a new production program.
The SY87729LHG is particularly relevant to networking equipment requiring Ethernet, Fibre Channel, or SONET/SDH/ATM clocking. A single output allows it to support a dedicated clock-generation channel, although system-level designs may require additional buffers, dividers, or distribution ICs. Differential PECL interfacing can reduce susceptibility to common-mode noise when the source and receiver use controlled impedance and properly terminated networks.
Designers should verify the complete pinout, reference requirements, jitter specifications, supply tolerances, and exposed-pad land pattern from the manufacturer datasheet before making a replacement. The exposed pad requires a low-impedance ground connection and adequate thermal copper. Differential input and output traces should have controlled impedance, short return paths, and symmetrical routing.
This product record combines the verified 365 MHz fractional-synthesizer specifications, package information, lifecycle status, and source links with explicit uncertainty markers where pricing and detailed electrical data were not available. It also separates genuinely verified drop-in alternatives from unverified cross-reference results so engineers can make a safer sourcing and redesign decision.
Аналоги без доработки для SY87729LHG — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
Для этого товара нет аналогов без доработки.
Запросить аналогиSY87729LHG Характеристики
| Product Type | Fractional-N clock synthesizer IC |
| Manufacturer | Microchip Technology |
| Series | AnyClock |
| Maximum Frequency | 365 MHz |
| Напряжение питания | 3.15 V minimum |
| Nominal Supply Voltage | 3.3 V |
| PLL | Yes |
| Number of Output Circuits | 1 |
| Input-to-Output Ratio | 1:1 |
| Input Signal Type | Differential PECL |
| Output Signal Type | Differential PECL |
| Primary Applications | Ethernet, Fibre Channel, SONET/SDH/ATM |
| Architecture | Monolithic fractional synthesizer |
| Корпус | 32-TQFP with exposed pad, 7 mm x 7 mm |
| Тип монтажа | Surface mount |
| Part Status | Obsolete |
Руководство по цоколевке SY87729LHG в корпусе 32-tqfp with exposed pad, 7 mm x 7 mm
Цоколевка для SY87729LHG (корпус 32-tqfp with exposed pad, 7 mm x 7 mm). Нумерация выводов, функции и схемы подключения определены в техническом описании производителя. Обратитесь к нему для точного посадочного места и рекомендаций по пайке.
Нет подробных данных о распиновке для SY87729LHG.
Обратитесь к даташиту для полной конфигурации выводов.
Типичное применение
SY87729LHG подходит для 6 применениеs: Ethernet Network Clock Generation, Fibre Channel Interface Support, SONET/SDH/ATM Equipment, Legacy Network Equipment Maintenance, Communications Timing Distribution, Industrial Data and Control Equipment.
Ethernet Network Clock Generation
The SY87729LHG fits legacy Ethernet infrastructure equipment that requires a differential clock derived from an external reference. Its fractional-N PLL architecture supports flexible frequency synthesis, while the 1:1 input-to-output ratio and 365 MHz maximum frequency make it suitable for qualified communications clock paths. The PECL output should be routed with controlled impedance and terminated according to the receiver requirements. Because the device is obsolete, a new network design should verify jitter, reference quality, and supply tolerance against the manufacturer datasheet rather than relying only on the headline frequency.
Рекомендуется
Fibre Channel Interface Support
The SY87729LHG can supply a precise differential clock for legacy Fibre Channel equipment because its verified application list includes Fibre Channel and its synthesizer supports outputs up to 365 MHz. The 1:1 input-to-output architecture allows the reference relationship to remain straightforward in designs requiring a related clock signal. The implementation must include correct PECL termination, short traces, and return-path control. Interface-specific timing margins and jitter limits should be checked against the Fibre Channel target specification and the complete manufacturer datasheet before production use.
Рекомендуется
SONET/SDH/ATM Equipment
The SY87729LHG is appropriate for legacy SONET/SDH/ATM clocking subsystems where a fractional synthesizer and differential PECL output are required. Its monolithic implementation reduces the number of separate synthesis blocks, while the 365 MHz ceiling supports high-speed communications infrastructure. The system designer still needs to account for reference phase noise, output jitter, deterministic latency, and transmission-line loading. Use the obsolete status to justify careful lifecycle management and preferably bench-validate a replacement or equivalent clock source before field deployment.
Рекомендуется
Legacy Network Equipment Maintenance
The SY87729LHG is most directly relevant to maintenance of installed networking equipment where the original board uses a 32-TQFP fractional clock synthesizer. Because the part is obsolete, using qualified residual inventory can avoid a risky board respin when the footprint, electrical limits, and timing behavior match exactly. Buyers should request traceability, condition details, and a quotation that recognizes the lifecycle risk. Before installation, inspect the package for storage damage and compare the replacement lot’s marking and electrical characteristics with the original system requirements.
Рекомендуется
Communications Timing Distribution
The SY87729LHG can serve as the source stage in a communications timing tree when one differential PECL clock is needed before distribution through separate buffers. Its fractional PLL and 1:1 ratio simplify reference-derived clock generation compared with a fixed-divider arrangement. The single-output count is a limitation for systems requiring several independently programmable clocks, so additional synthesis or distribution stages may be necessary. Maintain matched impedance and symmetrical routing between the synthesizer, distribution IC, and endpoint devices to limit deterministic skew and avoid differential-signal imbalance.
Рекомендуется
Industrial Data and Control Equipment
The SY87729LHG may be used in legacy industrial data and control equipment when a synchronization reference must be shared by high-speed communications circuitry. Differential PECL can support reliable clock transfer over controlled-impedance interconnects, although industrial temperature and EMC requirements must be checked because those limits are absent from the supplied records. The exposed thermal pad also requires careful copper and via layout. Since the device is obsolete, engineers should document the original timing budget and qualify any proposed alternative against long-term supply availability as well as electrical compatibility.
Рекомендуется
Сводка рекомендуемых товаров
Справочные инженерные данные для SY87729LHG — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар |
|---|---|
| Brand | Microchip Technology |
| Package | 32-TQFP with exposed pad, 7 mm x 7 mm |
| Product Type | Fractional-N clock synthesizer IC |
| Maximum Frequency | 365 MHz |
| Supply Voltage | 3.15 V minimum; nominal 3.3 V class |
| Output Circuits | 1 |
| Input-to-Output Ratio | 1:1 |
| Input Signal | Differential PECL |
| Output Signal | Differential PECL |
| PLL | Yes |
| Primary Applications | Ethernet, Fibre Channel, SONET/SDH/ATM |
| Lifecycle Status | Obsolete |
Ключевые отличия
- Single-output fractional-N architecture with a stated 1:1 input-to-output ratio (против Unverified alternative candidates)
- Communications-oriented application coverage (против Unverified alternative candidates)
- High stated maximum frequency in an exposed-pad package (против Unverified alternative candidates)
Заметки по проектированию
Treat the SY87729LHG reference, PECL input, and PECL output paths as controlled-impedance differential routes. Keep the input and output connections short, maintain symmetrical spacing, and provide a continuous return plane beneath the traces. Locate termination components close to the receiving device rather than at the synthesizer, because placement changes edge rate, reflection, and deterministic jitter.
The 32-TQFP exposed pad requires deliberate thermal and electrical planning. After confirming the pad's assigned net in the manufacturer datasheet, provide the recommended copper area and vias without violating clock-signal return paths. Use an estimated power-dissipation calculation from the actual supply, output current, and datasheet efficiency before deciding whether additional thermal spreading is required.
Do not assume that another fractional synthesizer with a 32-pin TQFP is pin compatible. Verify the power, ground, reference, feedback, serial-programming, test, and clock-output pins individually, then compare supply tolerance, PLL range, output amplitude, jitter, and termination voltage. Because the SY87729LHG is obsolete, preserve the original land pattern and document any board changes required for a supported replacement.
Keep the 3.3 V supply path low impedance and place local high-frequency decoupling at the device's supply pins as recommended by the manufacturer. Confirm the exposed-pad connection and permissible voltage before placing capacitors or test points on that net. Reference-ground current from decoupling should return through a low-impedance path rather than through sensitive clock traces.
Информация о соответствии
The supplied verified records identify the manufacturer, package, functional characteristics, and obsolete lifecycle status but do not extract RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals declarations.
