SY75578LMG - 267MHz 1:8 HCSL Clock Fanout Buffer | Microchip
Référence : SY75578LMG ✓ ActifSY75578LMG Présentation
A clock fanout buffer is a clock distribution circuit that receives one differential clock and generates multiple identical output copies. The SY75578LMG belongs to the clock buffer and driver hierarchy, where low jitter, controlled skew, differential signaling, and repeatable output characteristics are essential for transferring timing signals across a PCB. Its 1:8 fanout ratio allows one source clock to feed eight destination circuits without recreating the original clock eight times.
Key features include acceptance of HCSL or LVDS input signals, generation of HCSL output levels, two input paths with multiplexing, eight identical output copies, and operation from a 3.3 V supply with a tolerance of plus or minus 5%. The 130 fs phase-jitter figure supports precise high-speed timing, while the maximum 100 ps output-to-output skew establishes the permitted variation among the eight outputs.
The fully differential architecture is designed for PCI Express clock-distribution requirements. Differential signaling provides noise immunity on circuit-board interconnects, while the internal fanout stage creates eight matched clock outputs for endpoints, switches, retimers, serializers, or test equipment. The exposed-pad QFN construction supports heat transfer through the PCB, although the thermal requirements of the exact carrier board and loading must be evaluated during layout review.
Typical uses include PCI Express reference-clock distribution, server and workstation backplanes, high-speed interface test systems, networking equipment, and industrial control boards that need multiple low-skew differential clock copies. In a PCI Express design, the device can distribute a common 267 MHz-class reference clock to multiple lanes or downstream circuits while maintaining consistent phase relationships.
PCB design requires short, symmetric differential routes, continuous reference planes, controlled impedance, and careful placement of the exposed-pad thermal and electrical connections. Decoupling capacitors should be positioned close to the supply and ground pins. Input and output return paths should avoid discontinuities, and the unused clock inputs must be connected according to the manufacturer datasheet rather than left floating.
This page combines the manufacturer clock-performance specifications, package details, application guidance, comparison parameters, and practical layout considerations. It also distinguishes a genuine same-package replacement from merely similar clock buffers so that engineers can evaluate drop-in decisions without changing PCB geometry or timing requirements.
Alternatives de remplacement direct pour SY75578LMG — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
SY75578L
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
SY75578LMG Spécifications
| Device Type | Fully differential clock fanout buffer |
| Fréquence d'horloge maximale | 267 MHz |
| Fanout Ratio | 1:8 |
| Output Count | 8 outputs |
| Input Count | 2 inputs |
| Input Logic Levels | HCSL or LVDS |
| Output Logic Levels | HCSL |
| Phase Jitter | 130 fs |
| Maximum Output-to-Output Skew | 100 ps |
| Tension d'alimentation | 3.3 V ±5% |
| Supply Tolerance | ±5% |
| Boîtier | 32-pin QFN, 5 mm x 5 mm |
| Exposed Pad | Present |
| Type de montage | Surface mount |
Guide de configuration des broches du SY75578LMG 32-pin qfn, 5 mm x 5 mm
Configuration des broches du SY75578LMG (boîtier 32-pin qfn, 5 mm x 5 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 SY75578LMG.
Consultez la fiche technique pour la configuration complète des broches.
Applications typiques
SY75578LMG convient pour 6 applications: PCI Express Reference-Clock Distribution, PCI Express Lane Reference Distribution, High-Speed Interface Test Equipment, Networking and Backplane Clock Distribution, Server Platform Clock Distribution, Industrial High-Speed Control Systems.
PCI Express Reference-Clock Distribution
The SY75578LMG fits PCI Express reference-clock distribution because it converts one selected differential source clock into eight HCSL copies at up to 267 MHz. According to the Microchip Technology SY75578L datasheet, the two input paths support multiplexing, while 130 fs phase jitter and 100 ps maximum output-to-output skew provide tightly controlled clock relationships. Place the buffer near the source clock or distribution junction, then route each differential output as a length-balanced pair over a continuous reference plane. PCB loss, receiver loading, and the complete system timing budget should still be verified with the actual endpoint configuration.
Recommandé
PCI Express Lane Reference Distribution
The SY75578LMG is suitable for supplying common reference clocks to several PCI Express lanes, endpoints, switches, or retimers. Its eight identical HCSL outputs let one low-jitter source support multiple destinations while maintaining no more than 100 ps output-to-output skew. According to the Microchip Technology SY75578L datasheet, the buffer accepts HCSL or LVDS inputs and operates to 267 MHz. Engineers should assign outputs to the shortest practical receivers, match each differential pair, preserve impedance continuity, and avoid introducing unnecessary stubs that could disturb the differential clock waveform.
Recommandé
High-Speed Interface Test Equipment
The SY75578LMG provides the low-skew multi-copy clock required by high-speed interface test systems that compare phase and timing behavior across several channels. Its 1:8 topology allows one differential source to feed eight measurement destinations, and the specified 130 fs phase jitter helps maintain a clean timing reference. According to the Microchip Technology SY75578L datasheet, the maximum output-to-output skew is 100 ps at the supported clock rate. In instrumentation, isolate the reference distribution from noisy test signals and use controlled impedance so probe, fixture, and cable effects do not obscure device performance.
Recommandé
Networking and Backplane Clock Distribution
The SY75578LMG supports networking and backplane designs that need one high-quality reference distributed to multiple high-speed circuits. Its fully differential architecture and HCSL outputs are suited to board-level clock routing, while 130 fs phase jitter and 100 ps maximum output skew help maintain channel-to-channel timing consistency at up to 267 MHz. According to the Microchip Technology SY75578L datasheet, the buffer accepts either HCSL or LVDS differential inputs. Backplane implementation should account for connector loss, return loss, layer transitions, and receiver thresholds rather than relying only on the IC specifications.
Recommandé
Server Platform Clock Distribution
The SY75578LMG can distribute a common differential clock to multiple server interface blocks when a low-jitter, tightly skewed source is required. Its eight HCSL outputs provide a practical fanout without recreating the source clock at every endpoint, and the 267 MHz operating limit matches the device’s PCI Express optimization. According to the Microchip Technology SY75578L datasheet, phase jitter is specified at 130 fs and output-to-output skew at no more than 100 ps. Thermal and EMC performance depend on the server board stack-up and enclosure, so prototype measurements remain important near high-speed edges and power sources.
Recommandé
Industrial High-Speed Control Systems
The SY75578LMG can distribute a common clock to multiple industrial high-speed acquisition, control, or communication blocks that must operate from a coherent reference. Differential HCSL signaling improves noise immunity, while the 1:8 fanout and maximum 100 ps output skew help maintain repeatable timing across distributed destinations. According to the Microchip Technology SY75578L datasheet, the device accepts HCSL or LVDS input and supports operation to 267 MHz. Industrial boards should separate clock routing from switching power and noisy motor or relay paths, and should verify operation across the complete temperature range of the finished system.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour SY75578LMG — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | SY75578L |
|---|---|---|
| Package | 32-QFN (5x5 mm) | 32-QFN (5x5 mm) |
| Brand | Microchip Technology | Microchip Technology |
| Product Type | Fully differential clock fanout buffer | Fully differential clock fanout buffer |
| Maximum Frequency | 267 MHz | 267 MHz |
| Fanout Ratio | 1:8 | 1:8 |
| Input Configuration | 2 inputs with multiplexing | 2 inputs with multiplexing |
| Input Logic Levels | HCSL or LVDS | HCSL or LVDS |
| Output Logic Levels | HCSL, 8 outputs | HCSL, 8 outputs |
| Phase Jitter | 130 fs | 130 fs |
| Maximum Output-to-Output Skew | 100 ps | 100 ps |
| Supply Voltage | 3.3 V ±5% | 3.3 V ±5% |
Principaux différenciateurs
- Eight-output differential fanout in one clock buffer (vs SY75578L)
- Low phase-jitter clock replication (vs SY75578L)
- Controlled channel-to-channel timing (vs SY75578L)
Notes de conception
Route every HCSL or LVDS clock connection as a tightly coupled differential pair over a continuous reference plane. Match the pair length within the amount allowed by the system timing budget, avoid right-angle disconnects, and minimize vias and stubs. Keep the eight output routes electrically similar so their propagation behavior does not consume the specified 100 ps maximum output-to-output skew allowance.
Place input, output, and bypass components close to their associated pins. Follow the manufacturer pin-description table for the exposed-pad connection and preserve a low-impedance path from the exposed pad into the relevant ground plane. Provide clean supply and ground return paths around the clock buffer, and keep high-current switching-node copper and inductors away from the differential clock inputs to reduce added jitter and crosstalk.
Do not treat a shared package as sufficient proof of drop-in compatibility. Verify the exact pin assignments, input thresholds, output amplitude, supply tolerance, temperature grade, and exposed-pad requirements before substituting another MPN. Likewise, do not leave unused clock inputs floating; terminate or configure them exactly as directed by the Microchip Technology SY75578L datasheet to prevent unpredictable clock behavior or excess noise.
Validate the complete clock path with the target source, connectors, receivers, and PCB stack-up. A nominal 267 MHz operating point does not guarantee acceptable eye opening or compliance in every channel. Probe at each receiver when practical, confirm differential voltage and common-mode behavior, and test worst-case loading and temperature conditions. Account for connector and cable return loss when the fanout crosses a backplane or test fixture.
The exposed pad provides the principal path for heat removal from the 32-pin QFN. Connect it to the recommended ground structure and use adequate copper area, thermal vias, and a controlled board environment. Power loss is primarily associated with clock-buffer output current and supply dissipation, so use the actual output loading and voltage difference when estimating thermal performance; prototype the finished stack-up rather than relying on a package-only assumption.
Informations de conformité
The manufacturer datasheet and package information identify the device and its electrical characteristics; no specific RoHS, REACH, lead-free, halogen-free, or conflict-minerals declaration was identified for this ordering code.
