Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Clock/Timing > Clock Buffers, Drivers

Renesas 551MILF

Name: 551MILF
Brand: Renesas
SKU: 551MILF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: 551MILF

Manufacturer:: Renesas

Category:: Clock Buffers, Drivers

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: 551MILF.pdf

Description:: IC CLK BUFFER 1:4 160MHZ 8SOIC

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:3,916

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

551MILF from IDT is a single-input, four-output non-inverting clock buffer IC designed for fan-out distribution in timing-critical systems. It supports input/output frequencies up to 160 MHz, delivers 250 ps output-to-output skew, operates at 3.3 V or 5.0 V, and features Output Enable (OE) control with internal pull-up. It is used in networking clock distribution where low-cost, low-skew signal replication is required.

For engineers reviewing the 551MILF datasheet, 551MILF pinout, 551MILF application, or 551MILF equivalent, key selection criteria include industrial-temperature operation (-40°C to +85°C), SOIC-8 packaging, tri-state output enable functionality, and compatibility with both 3.3 V and 5.0 V logic domains.

Technical Context

The 551MILF implements a passive, non-PLL clock fan-out architecture with no internal frequency synthesis or phase alignment. All four outputs replicate the ICLK input with identical duty cycle and minimal propagation delay variation.

It uses advanced low-power CMOS process technology and integrates internal pull-up resistors on ICLK and OE pins. The device supports dual supply voltage operation (3.3 V or 5.0 V), and its outputs are CMOS-compatible with 20 Ω nominal output impedance and rail-to-rail swing capability under specified load conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
Input/Output Frequency	Up to 160 MHz - supports high-speed Ethernet, PCI Express reference clocks, and DDR memory interface timing.
Output-to-Output Skew	250 ps max - ensures tight timing alignment across four downstream clock domains without external deskew circuitry.
Supply Voltage Range	3.0–3.6 V or 4.5–5.5 V - enables direct integration into mixed-voltage systems without level-shifting.
Propagation Delay	1.5–6 ns (typ–max at 135 MHz) - predictable latency for synchronous system timing budgeting.
Operating Temperature	-40°C to +85°C - qualified for industrial-grade embedded and networking equipment deployment.
Output Enable Function	Active-low OE pin - allows dynamic clock gating and power management of downstream logic blocks.
Package	8-pin SOIC (150 mil) - standard footprint compatible with automated PCB assembly and legacy board designs.

Pinout & Package

551MILF is packaged in an 8-pin SOIC (150 mil narrow body) per JEDEC MS-012, with 1.27 mm pitch and 5.0 mm × 4.0 mm body dimensions.

Pin/Terminal	Circuit Role	Design Meaning
1 (ICLK)	Clock input	Single-ended CMOS clock input with internal pull-up; accepts 0–160 MHz signals and drives all four outputs.
2 (Q1)	Clock output	Non-inverting buffered copy of ICLK; CMOS output with 20 Ω impedance and rail-to-rail swing.
3 (Q2)	Clock output	Identical to Q1 - matched delay and skew relative to ICLK and other outputs.
4 (Q3)	Clock output	Third buffered output; electrically and temporally aligned with Q1–Q4 for parallel clock distribution.
5 (Q4)	Clock output	Fourth output; enables one-to-four fan-out without external buffers or discrete logic.
6 (GND)	Power ground	Reference node for all I/O and internal circuitry; requires local 0.01 µF decoupling capacitor.
7 (VDD)	Power supply	Single supply pin supporting either 3.3 V or 5.0 V; powers all internal logic and output drivers.
8 (OE)	Output enable	Active-low control: pulls all Q1–Q4 into high-impedance state when low; internal 220 kΩ pull-up ensures default active state.

Key Features

Feature	Design Value
Low output skew	250 ps max between any two outputs - eliminates need for external matching traces or delay compensation.
Tri-state output control	Hardware-enabled clock gating via OE pin - supports dynamic power-down of downstream clock trees.
Dual supply compatibility	Operates natively at 3.3 V or 5.0 V - avoids level shifters in mixed-voltage timing subsystems.
Pb-free SOIC packaging	RoHS-compliant 8-pin SOIC with "LF" suffix - meets environmental compliance requirements without derating.
Industrial temperature range	-40°C to +85°C operation - validated for use in base station radios, industrial controllers, and outdoor networking gear.

Applications

Networking Clock Distribution	PCI Express Reference Clock Fan-Out
Use Scenario: Distributing a single 100 MHz reference clock to multiple PHY layers in a multi-port Ethernet switch ASIC. IC Role / Device Role / Timing Role: Fan-out buffer replicating and isolating the master clock to four independent MAC/PHY interfaces. Use Value: Maintains 250 ps inter-output skew to meet IEEE 802.3 jitter budgets without requiring individual trace-length tuning.	Use Scenario: Providing synchronized 100 MHz REFCLK to four PCIe Gen2 endpoints on a server motherboard. IC Role / Device Role / Timing Role: Low-skew clock repeater ensuring simultaneous clock arrival across PCIe slots with shared reference source. Use Value: Eliminates need for four separate clock generators or complex PLL-based distribution, reducing BOM count and layout complexity.
Industrial PLC Timing Subsystem	DDR Memory Interface Clock Buffering
Use Scenario: Driving real-time I/O module clocks and FPGA configuration clocks in a programmable logic controller operating in harsh environments. IC Role / Device Role / Timing Role: Industrial-temperature clock distributor enabling deterministic timing across distributed control modules. Use Value: -40°C to +85°C qualification and 3.3 V/5.0 V flexibility allow direct integration into legacy 5 V backplanes and modern 3.3 V FPGAs.	Use Scenario: Replicating a 200 MHz system clock to DDR2 SDRAM controller, memory PHY, termination bias generator, and debug trace clock domains. IC Role / Device Role / Timing Role: Non-inverting fan-out buffer preserving duty cycle integrity and minimizing inter-clock domain skew. Use Value: Matches incoming duty cycle per spec and delivers sub-nanosecond rise/fall times (1.0 ns typ), meeting DDR2 setup/hold margin requirements.

Networking Clock Distribution

PCI Express Reference Clock Fan-Out

Use Scenario: Distributing a single 100 MHz reference clock to multiple PHY layers in a multi-port Ethernet switch ASIC.

IC Role / Device Role / Timing Role: Fan-out buffer replicating and isolating the master clock to four independent MAC/PHY interfaces.

Use Value: Maintains 250 ps inter-output skew to meet IEEE 802.3 jitter budgets without requiring individual trace-length tuning.

Use Scenario: Providing synchronized 100 MHz REFCLK to four PCIe Gen2 endpoints on a server motherboard.

IC Role / Device Role / Timing Role: Low-skew clock repeater ensuring simultaneous clock arrival across PCIe slots with shared reference source.

Use Value: Eliminates need for four separate clock generators or complex PLL-based distribution, reducing BOM count and layout complexity.

Industrial PLC Timing Subsystem

DDR Memory Interface Clock Buffering

Use Scenario: Driving real-time I/O module clocks and FPGA configuration clocks in a programmable logic controller operating in harsh environments.

IC Role / Device Role / Timing Role: Industrial-temperature clock distributor enabling deterministic timing across distributed control modules.

Use Value: -40°C to +85°C qualification and 3.3 V/5.0 V flexibility allow direct integration into legacy 5 V backplanes and modern 3.3 V FPGAs.

Use Scenario: Replicating a 200 MHz system clock to DDR2 SDRAM controller, memory PHY, termination bias generator, and debug trace clock domains.

IC Role / Device Role / Timing Role: Non-inverting fan-out buffer preserving duty cycle integrity and minimizing inter-clock domain skew.

Use Value: Matches incoming duty cycle per spec and delivers sub-nanosecond rise/fall times (1.0 ns typ), meeting DDR2 setup/hold margin requirements.

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock buffer applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ICS552MLF	Dual 1-to-2 buffer in 20-pin QSOP; higher pin count, separate enable per channel.	Used when independent control of two clock domains is needed instead of unified 1-to-4 fan-out.	Select 551MILF for cost-sensitive, space-constrained 1-to-4 distribution; choose ICS552MLF only if channel isolation or dual-buffer topology is required.
PI6C20400LEX	1-to-4 LVCMOS buffer with 1.8 V/2.5 V/3.3 V support; lower max frequency (125 MHz); different pinout.	Suitable for low-voltage, battery-powered systems where 160 MHz operation is unnecessary.	551MILF remains preferred for industrial-temperature, 160 MHz, and dual-supply applications; PI6C20400LEX fits ultra-low-power or 1.8 V–only designs.

Compared with ICS552MLF and PI6C20400LEX, the 551MILF uniquely balances industrial temperature rating, 160 MHz bandwidth, SOIC-8 compactness, and dual-supply operation - making it optimal for cost-driven, high-reliability clock fan-out where unified enable control and minimal PCB area are critical.

Availability

551MILF is available at Aetrix Electronics and suitable for networking infrastructure, industrial PLCs, and DDR memory interface designs requiring stable component supply, RoHS compliance, and guaranteed industrial-temperature performance.

Supply support for 551MILF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Integrated Device Technology (IDT), now part of Renesas Electronics, is a fabless semiconductor company specializing in timing, memory interface, RF, and sensor solutions for communications and computing markets.

The 551MILF belongs to IDT's ClockBlocks™ family of low-cost, low-skew clock buffers, engineered specifically for high-volume, cost-sensitive applications requiring reliable fan-out without PLL complexity.

FAQ

What is the maximum operating frequency supported by the 551MILF?

The 551MILF supports input and output clock frequencies up to 160 MHz under 3.3 V operation and up to 135 MHz under 5.0 V operation, as specified in its AC electrical characteristics table. This makes the 551MILF suitable for high-speed applications including Gigabit Ethernet PHY clocks and PCIe Gen2 reference timing. The 551MILF maintains full functionality and skew specifications across this range.

Does the 551MILF require external pull-up or pull-down resistors on its control pins?

No - the 551MILF integrates internal pull-up resistors on both the ICLK and OE pins (220 kΩ on OE, 500 kΩ on ICLK), eliminating the need for external biasing components. This simplifies design and reduces bill-of-materials count. The 551MILF defaults to enabled operation due to the OE pin's internal pull-up, allowing immediate clock distribution upon power-up unless actively disabled.

Can the 551MILF operate from both 3.3 V and 5.0 V supplies simultaneously?

No - the 551MILF has a single VDD pin and must be powered from either 3.3 V (3.0–3.6 V) or 5.0 V (4.5–5.5 V), not both. It does not support mixed-supply operation. The 551MILF's I/O structure is designed to be compatible with the selected supply voltage, and its outputs swing rail-to-rail relative to that VDD. Selecting the correct voltage grade during design ensures proper interfacing with downstream logic families.

What is the purpose of the OE pin on the 551MILF, and how does it behave electrically?

The OE (Output Enable) pin on the 551MILF is an active-low control that places all four Q1–Q4 outputs into high-impedance state when driven low. When OE is high (or left floating, due to its internal pull-up), outputs are active and replicate ICLK. The 551MILF's OE pin has 5 pF input capacitance and is compatible with standard CMOS logic thresholds, enabling direct connection to microcontroller GPIO or FPGA control signals without buffering.

Is the 551MILF pin-compatible with other members of the ICS551 family, such as the 551MLF?

Yes - the 551MILF shares identical pinout, package (8-pin SOIC), and electrical interface with the commercial-grade 551MLF and 551MLN variants. The only functional difference is the extended industrial temperature range (-40°C to +85°C) of the 551MILF, while maintaining identical AC/DC specifications, timing behavior, and enable functionality. This allows drop-in replacement in thermally demanding applications without layout changes.

551MILF Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Series:: ClockBlocks™

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Active

Type:: Fanout Buffer (Distribution)

Number of Circuits:: 1

Ratio - Input:Output:: 1:4

Differential - Input:Output:: No/No

Input:: CMOS

Output:: CMOS

Frequency - Max:: 160 MHz

Voltage - Supply:: 3V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

Supplier Device Package:: 8-SOIC

551MILF FAQ

1.How can I place an order for 551MILF through Aetrix?

Please submit a Request for Quotation (RFQ) for 551MILF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 551MILF reliable?

The price and inventory of 551MILF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 551MILF is usually 5 days.

3.What payment methods are accepted for 551MILF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 551MILF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 551MILF?

551MILF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 551MILF order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 551MILF?

For technical support, including 551MILF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 551MILF requirements.

6.How does Aetrix verify that 551MILF is sourced from the original manufacturer or authorized distributors?

All 551MILF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 551MILF meets industry standards.

7.What is the process for return or replacement of 551MILF?

All 551MILF units undergo pre-shipment inspection (PSI). If there is an issue with 551MILF, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 551MILF part is unused and in its original packaging.

Return procedure for 551MILF:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…