Renesas Electronics 557GI-08LFT PCI Express Clock Multiplexer IC Equivalent & Substitute Parts

Part Overview

The Renesas Electronics 557GI-08LFT is a PCI Express (PCIe) Clock Multiplexer IC designed for high-speed clock distribution in PCIe applications. This 16-TSSOP surface mount device operates at a maximum frequency of 200MHz with a 2:1 input-to-output ratio, supporting both HCSL and LVDS signal standards. The part is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Substiute Parts

557GI-08LFT

Renesas Electronics CorporationIn Stock: 1102557GI-08LFT Datasheet

Current PartRFQ

9DML0441AKILFT

Renesas Electronics CorporationIn Stock: 36199DML0441AKILFT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 557GI-08LFT is determined by the following critical parameters:

Core Functional Requirements:

• PCI Express (PCIe) clock multiplexer application
• Maximum frequency operation at 200MHz
• Differential input and output capability (Yes/Yes)
• Supply voltage range: 3.135V ~ 3.465V
• Operating temperature range: -40°C ~ 85°C
• Number of circuits: 1

Acceptable Variation Parameters:

• Input/output ratio may differ (2:1 vs. 2:4) provided the device supports the required clock distribution topology
• Package type may change from 16-TSSOP to alternative surface mount packages (such as 24-VFQFN) without functional impact, provided PCB layout accommodates the new footprint
• Signal standard support (HCSL/LVDS) may be subset or superset of original specification
• Product status transition from obsolete to active is acceptable for forward compatibility

The substitute part 9DML0441AKILFT meets these criteria through equivalent frequency performance, identical supply voltage specifications, matching temperature range, and active product status with improved availability.

Parameter Comparison

Engineering Selection Recommendations

The 9DML0441AKILFT is the manufacturer-recommended substitute for the obsolete 557GI-08LFT. Selection of this alternative is supported by the following engineering factors:

Functional Equivalence: Both devices operate at identical maximum frequency (200MHz), supply voltage range (3.135V ~ 3.465V), and temperature specifications (-40°C ~ 85°C). Both maintain differential input and output capability required for PCIe clock distribution.

Product Status and Compliance: The substitute part holds active product status, ensuring long-term availability and manufacturing support. The 9DML0441AKILFT carries ROHS3 compliance certification, meeting current environmental and regulatory requirements. Both parts maintain identical REACH and ECCN classifications.

Package Consideration: The transition from 16-TSSOP to 24-VFQFN represents a footprint change requiring PCB layout modification. The 24-VFQFN package provides an exposed pad for improved thermal performance. This change is acceptable provided the application circuit topology accommodates the increased pin count (24 vs. 16 pins) and the 2:4 output ratio aligns with system clock distribution requirements.

Inventory and Supply: The substitute part maintains significantly higher inventory availability (3588 Pcs vs. 1043 Pcs), supporting both immediate procurement needs and long-term supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can the 9DML0441AKILFT directly replace the 557GI-08LFT without circuit modification?

A: Direct pin-for-pin replacement is not possible due to package differences (16-TSSOP vs. 24-VFQFN) and increased pin count. PCB layout redesign is required. However, the functional performance and electrical specifications are equivalent, supporting circuit-level substitution with appropriate layout changes.

Q: What is the significance of the different input/output ratios (2:1 vs. 2:4)?

A: The 557GI-08LFT provides one output clock from two input clocks (2:1 ratio). The 9DML0441AKILFT provides four output clocks from two input clocks (2:4 ratio). Selection depends on the number of clock outputs required by the system. If only one output is needed, the additional outputs on the substitute part remain unused but do not affect functionality.

Q: Are there signal standard compatibility concerns between HCSL/LVDS support differences?

A: The main part supports both HCSL and LVDS input/output standards. The substitute part supports HCSL only. If the application requires LVDS signal compatibility, this substitution is not suitable. If the application uses HCSL exclusively, the substitute part is fully compatible.

Q: What are the implications of the package change from 16-TSSOP to 24-VFQFN?

A: The 24-VFQFN package is physically larger (4x4mm footprint) compared to 16-TSSOP (4.40mm width). The exposed pad on the VFQFN package provides superior thermal dissipation. PCB redesign is mandatory, including trace routing, via placement, and thermal management considerations. The change does not affect electrical performance.

Q: Is the substitute part suitable for new design implementations?

A: Yes. The 9DML0441AKILFT holds active product status and meets current compliance standards (ROHS3). It is appropriate for both legacy system support and new PCIe clock distribution designs, provided the application requirements align with the specified electrical parameters and package constraints.