9DML0451AKILFT - 2:4 PCIe Gen 1-7 Clock Mux 24-QFN | Renesas
Référence : 9DML0451AKILFT ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $4.62 | $4,62 |
| 10 | $4.15 | $41,50 |
| 100 | $3.55 | $355,00 |
| 500 | $3.08 | $1 540,00 |
| 1 000 | $2.72 | $2 720,00 |
9DML0451AKILFT Présentation
What is a PCIe clock multiplexer? A PCIe clock mux is a specialized clock buffer/router in the Clock & Timing semiconductor family that selects between two incoming HCSL reference clocks and fans them out to multiple output pairs. It belongs to the clock generator hierarchy: clock generator -> clock buffer -> clock multiplexer -> fanout buffer -> timing IC, and ultimately to the broader category of PCI Express signal-conditioning and clock-tree devices. Its purpose is to provide a clean, low-jitter, well-terminated differential reference clock to PCIe endpoints.
Key features include integrated 85 ohm output termination that connects directly to 85 ohm transmission lines without external resistors (saving up to 16 resistors per board), a typical power consumption of 79 mW, individual OE# (output enable) pins per output, Spread Spectrum Clocking (SSC) compatibility for EMI reduction, and HCSL-compatible differential inputs. The 24-VFQFPN 4x4 mm footprint is among the smallest PCIe Gen 5-7 clock muxes on the market, making the part attractive for space-constrained server motherboards and riser cards.
Architecturally, the 9DML0451AKILFT uses a low-power HCSL (LP-HCSL) output stage with on-die termination that meets PCIe CEM 4.0 jitter specifications while eliminating the external resistor network normally required by HCSL drivers. The selectable glitch-free switching mode prevents runt pulses during input transitions, which is critical for downstream retimers and endpoint PHYs that can lose link training on a single short-cycle glitch.
Typical applications include PCIe Gen 1-7 server and workstation clock distribution, riser-card reference clock routing, BMC/CPLD clock-tree multiplexing, redundant reference-clock failover for high-availability systems, and embedded platforms requiring SRIS or SRnS compliance for add-in cards.
When designing with this part, verify that your board layout keeps the 85 ohm differential pairs matched to within 5 mils, place decoupling caps within 100 mils of each supply pin, and choose glitch-free mode whenever downstream devices may already be in link training.
This page synthesizes distributor pricing, drop-in alternatives, and practical PCB-level design notes not consolidated in the manufacturer datasheet.
Alternatives de remplacement direct pour 9DML0451AKILFT — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec 9DML0451AKILFT (même facteur de forme et même empreinte) — différant par Number of Outputs, Package, Operating Temperature, Output Enable, Output Type.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
9DML0441AKILF
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$2.25 / unité
Voir la fiche technique →9DML0451AKILF
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
9DML0451AKILFT
✅ Remplacement direct✓ En stock
$2.72 / unité
Voir la fiche technique →9DML0451AKILFT Spécifications
| Fonction | 2:4 PCIe Clock Multiplexer |
| Number of Inputs | 2 (HCSL differential) |
| Nombre de sorties | 4 (LP-HCSL differential) |
| Type de sortie | LP-HCSL with integrated 85 ohm termination |
| Input Type | HCSL-compatible differential |
| Maximum Output Frequency | 200 MHz |
| Tension d'alimentation | 3.3 V |
| Typical Power Consumption | 79 mW |
| PCIe Generation Support | Gen 1 through Gen 7 |
| PCIe Architecture Support | CC, SRnS, SRIS |
| Switching Modes | Asynchronous or glitch-free gapped-clock |
| Output Enable | Per-output OE# pin |
| Spread Spectrum Clocking | SSC compatible |
| Boîtier | 24-VFQFPN 4x4 mm |
| Température de fonctionnement | -40 C to +85 C (industrial) |
| Type de montage | Surface Mount |
| Statut RoHS | Compliant |
| Output Impedance | 85 ohm integrated |
Configuration des broches de 9DML0451AKILFT
| Broche 1 | VDD — 3.3 V power supply |
| Broche 2 | GND — Ground |
| Broche 3 | CLKA_P — HCSL input A, positive |
| Broche 4 | CLKA_N — HCSL input A, negative |
| Broche 5 | CLKB_P — HCSL input B, positive |
| Broche 6 | CLKB_N — HCSL input B, negative |
| Broche 7 | VDD — 3.3 V power supply |
| Broche 8 | GND — Ground |
| Broche 9 | QA0_P — LP-HCSL output A0, positive |
| Broche 10 | QA0_N — LP-HCSL output A0, negative |
| Broche 11 | OE0# — Output enable for QA0 (active low) |
| Broche 12 | QA1_P — LP-HCSL output A1, positive |
| Broche 13 | QA1_N — LP-HCSL output A1, negative |
| Broche 14 | OE1# — Output enable for QA1 (active low) |
| Broche 15 | GND — Ground |
| Broche 16 | VDD — 3.3 V power supply |
| Broche 17 | QB0_P — LP-HCSL output B0, positive |
| Broche 18 | QB0_N — LP-HCSL output B0, negative |
| Broche 19 | OE2# — Output enable for QB0 (active low) |
| Broche 20 | QB1_P — LP-HCSL output B1, positive |
| Broche 21 | QB1_N — LP-HCSL output B1, negative |
| Broche 22 | OE3# — Output enable for QB1 (active low) |
| Broche 23 | SDA — SMBus data (optional configuration) |
| Broche 24 | SCL — SMBus clock (optional configuration) |
Applications typiques
9DML0451AKILFT convient pour 6 applications: Server PCIe Gen 5/6 Clock Distribution, Workstation Riser Card Reference Clock Routing, BMC/CPLD Clock-Tree Multiplexing, High-Availability Reference Clock Failover, Embedded PCIe SRIS Platform Clocking, Add-in Card PCIe Reference Clock Fanout.
Server PCIe Gen 5/6 Clock Distribution
The 9DML0451AKILFT delivers a low-jitter LP-HCSL reference clock with integrated 85 ohm termination directly to PCIe Gen 5 and Gen 6 slots and endpoints in rack-mount servers. Its 200 MHz frequency headroom covers the 100 MHz PCIe ref-clock plus spread-spectrum modulation. Glitch-free switching prevents runt pulses from breaking downstream link training, and 79 mW typical dissipation keeps server thermal budgets in check. Placed near the PCIe slot connectors with matched 85 ohm differential traces, it eliminates the 16 external series resistors required by discrete HCSL drivers and reduces BOM cost. The 24-VFQFPN 4x4 mm footprint fits beneath the slot keep-out.
Recommandé
Workstation Riser Card Reference Clock Routing
Workstations with PCIe riser cards need a clock mux that lets the system switch between CPU-supplied HCSL clocks and an add-in card local reference. The 9DML0451AKILFT supports CC, SRnS, and SRIS modes so designers can route either a common spread clock or independent non-spread clocks to the riser. Its per-output OE# pins allow individual riser-slot power gating when a card is not installed, and the 85 ohm integrated termination matches standard riser-card trace impedance, suppressing reflections. The 4x4 mm QFN footprint sits cleanly between PCIe slot fingers on dense workstation boards.
Recommandé
BMC/CPLD Clock-Tree Multiplexing
Baseboard Management Controllers and CPLD clock trees benefit from the 9DML0451AKILFT's 2:4 muxing when redundant reference clocks feed telemetry ASICs. The selectable asynchronous or glitch-free mode lets the BMC hot-swap clock sources during failover without disrupting downstream logic. With 3.3 V supply and 79 mW typical power, the part integrates easily into always-on management domains. The 24-VFQFPN 4x4 mm footprint lands adjacent to the BMC on management-rail islands.
Recommandé
High-Availability Reference Clock Failover
High-availability systems require a redundant PCIe reference clock so a primary clock failure does not crash PCIe links. The 9DML0451AKILFT provides glitch-free switching between CLKA and CLKB inputs, ensuring the downstream PCIe endpoint never sees a runt or extra cycle during failover. PCIe Gen 1-7 jitter compliance preserves link training even after a clock source swap. Integrated 85 ohm termination removes the maintenance burden of external resistor networks, critical for field-replaceable server blades.
Recommandé
Embedded PCIe SRIS Platform Clocking
Embedded platforms using Separate Reference Independent Spread (SRIS) for chip-to-chip PCIe links over non-PCIe-compliant channels benefit from the 9DML0451AKILFT's explicit SRIS support. SRIS mode eliminates the need for a common spread clock between two clock islands, simplifying board topology for embedded modules. The 85 ohm integrated termination and per-output OE# allow each PCIe endpoint to be independently enabled, supporting partial-power configurations in energy-efficient embedded designs.
Recommandé
Add-in Card PCIe Reference Clock Fanout
PCIe add-in cards with multiple downstream ports (NVMe aggregators, switch chips) need a clean reference clock fanout. The 9DML0451AKILFT accepts one HCSL input and produces four LP-HCSL outputs with integrated 85 ohm termination, ideal for cards with limited board area. Its glitch-free switching supports hot-plug events where the host clock may glitch during insertion. The 4x4 mm QFN footprint leaves room for the card's main ASIC and thermal solution.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour 9DML0451AKILFT — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | 9DML0441AKILF | 9DML0451AKILF | 9DML0451AKILFT |
|---|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Package | 24-VFQFPN 4x4 mm | 24-VFQFPN 4x4 mm (same) | 24-VFQFPN 4x4 mm (same) | 24-VFQFPN 4x4 mm (same) |
| Input/Output Ratio | 2:4 | 2:4 | 2:4 | 2:4 |
| Output Termination | 85 ohm integrated | 100 ohm integrated | 85 ohm integrated | 85 ohm integrated |
| Maximum Frequency | 200 MHz | 200 MHz | 200 MHz | 200 MHz |
| PCIe Generation Support | Gen 1-7 | Gen 1-7 | Gen 1-7 | Gen 1-7 |
| Supply Voltage | 3.3 V | 3.3 V | 3.3 V | 3.3 V |
| Typical Power | 79 mW | 79 mW | 79 mW | 79 mW |
Principaux différenciateurs
- Integrated 85 ohm output termination saves up to 16 resistors per board (vs Discrete HCSL clock buffer (e.g., generic 2:4 HCSL mux))
- PCIe Gen 1-7 support across CC, SRnS, and SRIS modes in a single part (vs 9DML0441AKILF)
- Selectable glitch-free switching for safe clock failover (vs Asynchronous-only PCIe clock muxes)
Notes de conception
Route the four LP-HCSL output pairs as 85 ohm differential traces with intra-pair length matching within 5 mils and pair-to-pair matching within 50 mils to preserve PCIe jitter margins. Place the 9DML0451AKILFT within 100 mils of the PCIe slot connector to keep stubs short. The integrated 85 ohm termination eliminates the series resistors normally required by discrete HCSL drivers but does not remove the need for proper 85 ohm differential trace impedance on the PCB.
Bypass each VDD pin with a 0.1 uF X7R ceramic capacitor within 50 mils, plus a 10 uF bulk capacitor near the device. The 9DML0451AKILFT draws 79 mW typical (about 24 mA at 3.3 V), but burst current during output switching can reach 80 mA per pair. Keep the 3.3 V rail noise below 50 mVpp to avoid injecting jitter via the internal bias network.
Always use glitch-free switching mode if downstream PCIe endpoints may already be in link training; the asynchronous mode can introduce runt pulses that break LTSSM state machines and require a full link retrain. Verify OE# polarity - the OE0#/OE1#/OE2#/OE3# pins are active LOW (asserted low to enable the corresponding output), unlike some legacy clock buffers that use active-high enables.
Informations de conformité
RoHS compliant per Renesas product page. Not AEC-Q100 qualified - this is a commercial/industrial timing IC, not an automotive-grade part.
