Renesas 85408BGLF Clock Fanout Buffer Equivalent & Substitute Parts

Part Overview

The Renesas 85408BGLF is a Clock Fanout Buffer (Distribution) IC with 1:8 output configuration operating at a maximum frequency of 700 MHz. This device features differential input and output support with LVDS output capability, housed in a 24-TSSOP surface mount package. The part is classified as obsolete, making identification of suitable substitute components essential for ongoing system support and new design implementations.

Substiute Parts

85408BGLF

Renesas Electronics CorporationIn Stock: 85085408BGLF Datasheet

Current PartRFQ

8P34S1208NBGI

Renesas Electronics CorporationIn Stock: 22528P34S1208NBGI Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 85408BGLF is determined by the following critical parameters:

Functional Requirements:

• Type: Fanout Buffer (Distribution) IC
• Differential input and output capability
• LVDS output support
• Input compatibility with differential signal standards

Performance Specifications:

• Maximum operating frequency must meet or exceed application requirements
• Supply voltage compatibility or regulated supply availability
• Operating temperature range suitability for the target environment

Physical Constraints:

• Surface mount package compatibility with PCB layout
• Pin count and footprint considerations for board redesign feasibility

The substitute part 8P34S1208NBGI meets these criteria as an active Fanout Buffer (Distribution) and Multiplexer IC from the same manufacturer with enhanced frequency capability and differential LVDS input/output support.

Parameter Comparison

Engineering Selection Recommendations

The 8P34S1208NBGI is the manufacturer-recommended substitute for the obsolete 85408BGLF. Both devices are ROHS3 compliant and carry unlimited moisture sensitivity ratings, ensuring equivalent environmental and regulatory compliance.

The substitute part offers enhanced performance with 1.2 GHz maximum frequency capability compared to the 700 MHz specification of the main part. The 2:8 input:output ratio provides multiplexing functionality in addition to fanout distribution. Both devices maintain differential LVDS input and output support.

Design integration requires evaluation of the following factors:

Supply Voltage: The substitute operates at 1.71V ~ 1.89V versus the main part's 3.135V ~ 3.465V. Power supply redesign or voltage regulation may be necessary.

Package Transition: The substitute uses a 28-WFQFN Exposed Pad package (5x5mm) versus the 24-TSSOP package of the main part. PCB layout modification is required.

Operating Temperature: The substitute supports -40°C ~ 85°C, extending the lower temperature limit compared to the main part's 0°C ~ 70°C range.

Input Signal Compatibility: The substitute accepts CML and LVDS inputs. Applications using HCSL, LVHSTL, LVPECL, or SSTL inputs require signal conditioning or alternative component selection.

Frequently Asked Questions (FAQ)

Q: Can the 8P34S1208NBGI directly replace the 85408BGLF without PCB modifications?

A: No. The substitute uses a different package type (28-WFQFN versus 24-TSSOP) and different pin configuration. PCB layout redesign is required. Additionally, the supply voltage differs significantly (1.71V-1.89V versus 3.135V-3.465V), necessitating power supply circuit modifications.

Q: What input signal types does the 8P34S1208NBGI support?

A: The substitute accepts CML and LVDS differential inputs. If your application requires HCSL, LVHSTL, LVPECL, or SSTL inputs, signal conversion circuitry or alternative components must be evaluated.

Q: Is the substitute suitable for applications requiring 700 MHz operation?

A: Yes. The 8P34S1208NBGI operates at frequencies up to 1.2 GHz, exceeding the 700 MHz requirement of the main part. Frequency headroom is available for this application class.

Q: Are there compliance or regulatory differences between the main part and substitute?

A: Both parts are ROHS3 compliant with unlimited MSL ratings. No compliance differences exist. Both carry EAR99 ECCN classification and REACH Unaffected status.

Q: What is the functional difference between the 1:8 and 2:8 configurations?

A: The main part accepts one differential input and distributes it to eight outputs. The substitute accepts two differential inputs and can route either input to eight outputs via multiplexing. Applications requiring single-input fanout must configure the substitute to use only one input channel.

Q: Does the extended operating temperature range of the substitute affect compatibility?

A: The substitute's -40°C ~ 85°C range encompasses the main part's 0°C ~ 70°C range. Applications operating within 0°C ~ 70°C experience no temperature-related compatibility issues. Applications requiring operation below 0°C benefit from the substitute's extended lower temperature limit.