SY87739LHI - 729MHz Fractional-N Synthesizer | Microchip
Référence : SY87739LHI ✓ ActifSY87739LHI Présentation
A fractional-N synthesizer is a clock-generation IC that derives an output clock from a stable reference while using fractional division to produce frequencies that are not limited to integer ratios of the reference. The SY87739LHI belongs to the broader clock and timing hierarchy: fractional-N frequency synthesizer, clock generator, timing IC, and integrated circuit. This makes it useful where a system requires a programmable or protocol-related clock while retaining the operational simplicity of a single-reference architecture.
The primary electrical features include a 10 MHz to 729 MHz synthesis range, a maximum characterized output frequency of 729 MHz, one differential PECL output, and 3.3 V operation. A 27 MHz reference allows the synthesizer to generate exact frequencies used by common transport protocols, with or without forward-error correction. Protocol transparency is important because the generated frequency can follow the required clock relationship rather than being limited to a fixed integer divider ratio.
The SY87739L integrates a complete rate-independent frequency-synthesis function in one IC. It is specified for Ethernet, Fibre Channel, SONET/SDH, and ATM clock-generation requirements, making it particularly relevant to optical transponders, line cards, clocking subsystems, and communications test equipment. Its differential PECL interface supports high-speed clock distribution, although board-level implementation still requires correct differential routing, controlled impedance, and power-supply decoupling.
Typical uses include SONET/SDH transponder reference generation, Fibre Channel interface clocking, Ethernet equipment clock synthesis, ATM networking hardware, optical transport modules, and laboratory communication test systems. Designers should confirm that the selected output frequency, reference configuration, PECL termination, and thermal conditions match the exact datasheet operating requirements before releasing production hardware.
PCB implementation requires careful treatment of the exposed pad and high-speed clock nets. The exposed pad should be connected to the ground plane through the manufacturer-recommended thermal-via pattern, while input, output, and supply connections should be kept short. PECL output biasing and any downstream termination must follow the reference circuit because incorrect termination can alter edge quality, current consumption, and clock amplitude.
This product record combines the verified manufacturer and distributor data with practical selection criteria for protocol timing, package-aware alternatives, and implementation considerations. It highlights where verified electrical data is available and marks undisclosed electrical, lifecycle, pricing, and pin-level information explicitly rather than inferring values that are not supported by the supplied sources.
Alternatives de remplacement direct pour SY87739LHI — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
SY87739LHY
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
SY87739LHI Spécifications
| Product Type | Protocol-transparent fractional-N frequency synthesizer |
| Tension d'alimentation | 3.3 V |
| Reference Input Frequency | 27 MHz |
| Output Frequency Range | 10 MHz to 729 MHz |
| Maximum Output Frequency | 729 MHz |
| Output Quantity | 1 output |
| Type de sortie | Differential PECL |
| Input Signal Type | PECL reference input |
| PLL | Yes |
| Supported Protocols | Ethernet, Fibre Channel, SONET/SDH, and ATM |
| Forward-Error-Correction Support | Frequency generation with or without FEC |
| Boîtier | 32-TQFP-EP (7x7 mm) |
| Nombre de broches | 32 pins |
| Type de montage | Surface mount |
Guide de configuration des broches du SY87739LHI 32-tqfp-ep (7x7 mm)
Configuration des broches du SY87739LHI (boîtier 32-tqfp-ep (7x7 mm)). La numérotation des broches, les fonctions et les schémas de connexion sont définis dans la fiche technique du fabricant. Consultez-la pour l'empreinte exacte et les directives de soudage.
Aucune donnée de brochage détaillée disponible pour SY87739LHI.
Consultez la fiche technique pour la configuration complète des broches.
Applications typiques
SY87739LHI convient pour 6 applications: SONET and SDH Transponder Clocking, Fibre Channel Interface Clocking, Optical Transport Transponder Modules, Ethernet Network Equipment, ATM Transport Equipment, Communications Test and Measurement.
SONET and SDH Transponder Clocking
The SY87739LHI fits SONET/SDH transponder subsystems that require a protocol-related clock derived from one 27 MHz reference. Its fractional-N architecture generates frequencies from 10 MHz to 729 MHz, while the differential PECL output supports high-speed downstream clocking. The manufacturer specifically identifies SONET/SDH among the supported transport protocols. In implementation, the output frequency must match the line-rate and FEC mode, and the PCB must preserve the integrity of the differential clock path. Local 3.3 V decoupling and short reference routing are necessary to prevent supply or reference noise from degrading timing performance.
Recommandé
Fibre Channel Interface Clocking
The SY87739LHI is suitable for Fibre Channel interface equipment that needs an exact, protocol-related differential clock. It converts a single 27 MHz source into an output spanning 10 MHz to 729 MHz and is explicitly listed for Fibre Channel applications. This flexibility supports line cards, transponders, and interface modules whose clock frequency depends on the transport configuration. The design should maintain controlled impedance between the PECL output and receiver, use the manufacturer's recommended termination arrangement, and isolate the clock from noisy switching stages. Phase-noise and RMS-jitter limits must be checked against the specific Fibre Channel channel requirement before production release.
Recommandé
Optical Transport Transponder Modules
Optical transponders benefit from the SY87739LHI because a single 27 MHz reference can produce the exact differential clock required by multiple transport protocols. The manufacturer highlights protocol transparency and generation with or without FEC, which makes the synthesizer useful when clock requirements vary with line rate or correction mode. The device operates from 3.3 V and provides one differential PECL output in a 32-TQFP-EP package. Board-level design should minimize clock-loop area, use a continuous reference ground plane, and apply the exposed-pad thermal-via pattern. Confirm output amplitude and jitter against the selected optical modulator and driver requirements.
Recommandé
Ethernet Network Equipment
The SY87739LHI can support Ethernet line cards, routers, and interface modules requiring a programmable protocol-transparent clock. Its 10 MHz to 729 MHz synthesis range covers high-speed communication-clock requirements, and the 27 MHz reference architecture simplifies the source arrangement compared with multiple unrelated oscillators. The differential PECL output is suitable for clock distribution into compatible transceiver circuitry when the board uses controlled impedance and proper biasing. Because the supplied data does not specify Ethernet-specific jitter categories or reference sensitivity, the final design must compare those parameters with the applicable interface standard and verify them using the manufacturer's electrical-characteristics tables.
Recommandé
ATM Transport Equipment
The SY87739LHI is explicitly identified for ATM applications, making it applicable to ATM transport modules, network-interface equipment, and legacy protocol interfaces that require exact synthesized clocks. A single 27 MHz source can drive a differential PECL output across the 10 MHz to 729 MHz range, reducing the need for multiple clock-generation paths when several supported transport rates must be accommodated. The protocol-transparent fractional-N behavior is valuable where the required frequency is not a simple integer division of the reference. Integration still requires careful output termination, a low-noise 3.3 V supply, and verification of the selected frequency, phase noise, and jitter against the ATM system requirement.
Recommandé
Communications Test and Measurement
The SY87739LHI is appropriate for communications test equipment that must reproduce exact protocol-related clock frequencies from a stable reference. Its fractional-N operation covers 10 MHz to 729 MHz and supports Ethernet, Fibre Channel, SONET/SDH, and ATM frequencies, allowing a compact instrument implementation without many dedicated synthesizer channels. The single differential PECL output should be routed to the test path through controlled-impedance connections and suitable termination. Equipment designers must evaluate phase noise, RMS jitter, output amplitude, and reference sensitivity against the measurement floor. Those values were not included in the supplied excerpts and must be obtained from the full Microchip datasheet before specifying instrument accuracy.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour SY87739LHI — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | SY87739LHY |
|---|---|---|
| Brand | Microchip Technology | Microchip Technology |
| Package | 32-TQFP-EP (7x7 mm) | 32-TQFP-EP (7x7 mm) - same |
| Product Type | Protocol-transparent fractional-N frequency synthesizer | Clock and timing fractional synthesizer |
| Output Frequency Range | 10 MHz to 729 MHz | 10 MHz to 729 MHz |
| Reference Input Frequency | 27 MHz | 27 MHz |
| Supply Voltage | 3.3 V | 3.3 V |
| Output Type | Differential PECL | Differential PECL |
| Output Quantity | 1 output | 1 output |
| Supported Protocols | Ethernet, Fibre Channel, SONET/SDH, and ATM | Ethernet, Fibre Channel, SONET/SDH, and ATM |
Principaux différenciateurs
- Single-reference protocol clock synthesis (vs SY87739LHY)
- Broad communications protocol coverage (vs SY87739LHY)
- Fractional-N frequency flexibility (vs SY87739LHY)
Notes de conception
Route the 27 MHz reference and differential PECL output over a continuous ground plane with controlled impedance and minimal stubbing. Keep the reference input away from switching-regulator inductors and high-current output paths, and avoid discontinuities beneath the clock routes. Use the exact Microchip reference schematic for input termination and output coupling because component values and topology were not included in the supplied excerpts.
The 32-TQFP-EP package requires its exposed pad to be connected to ground for electrical and thermal performance. Follow the manufacturer land pattern and place the recommended thermal-via array under or near the exposed pad. Verify actual junction temperature in the final enclosure rather than relying on package pitch alone, particularly where the surrounding equipment maintains high ambient temperature.
Place the local 3.3 V bypass capacitors directly beside the supply and ground pins, using the capacitance and ESR requirements stated in the full datasheet. Confirm the reference source and PECL interface can source the required current without excessive loading. Do not infer quiescent current, output amplitude, or supply-current limits from the general feature summary because those values were not present in the verified excerpts.
Do not treat the SY87739LHY cross-reference statement as a complete substitute qualification without checking ordering-code temperature grade, lifecycle status, and lot traceability. Also avoid assuming that protocol transparency guarantees a target output: the selected frequency must still be programmed and configured correctly. Validate reference amplitude, output termination, and required PLL settings against the complete manufacturer document.
Informations de conformité
The supplied verified data does not explicitly state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals compliance. These fields remain unknown rather than being inferred from the manufacturer or package.
