ICS551MT Clock Fanout Buffer Equivalent & Substitute Parts

Part Overview

The ICS551MT is a Clock Fanout Buffer (Distribution) IC manufactured by Renesas Electronics Corporation, designed for 1:4 clock distribution at frequencies up to 160 MHz in 8-SOIC surface mount packaging. This part is classified as obsolete, making substitute components necessary for new designs and ongoing production requirements. The ICS551MT operates across a 3V to 5.5V supply range with CMOS input and output logic levels, suitable for general-purpose clock distribution applications in digital systems.

Key Parameters

Parameter	Value
Type	Fanout Buffer (Distribution)
Ratio - Input:Output	1:4
Frequency - Max	160 MHz
Input Logic	CMOS
Output Logic	CMOS
Voltage - Supply	3V ~ 5.5V
Operating Temperature	0°C ~ 70°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution for the ICS551MT is determined by the following critical parameters: 1:4 input-to-output ratio, 8-SOIC package footprint, surface mount compatibility, and CMOS logic family. The maximum frequency specification of 160 MHz establishes the minimum performance threshold; substitute parts with equal or higher frequency ratings are electrically compatible. Supply voltage range overlap (3V to 5.5V) is required for direct substitution. All identified substitutes maintain identical package geometry and pinout compatibility, enabling direct board-level replacement without layout modifications.

Parameter Comparison

Parameter	ICS551MT	551MLFT	NB3N551DG	NB3N551DR2G	PI6C10804WE
Manufacturer	Renesas	Renesas	onsemi	onsemi	Diodes Incorporated
Product Status	Obsolete	Active	Active	Active	Discontinued at DiGi Electronics
Type	Fanout Buffer	Fanout Buffer	Fanout Buffer	Fanout Buffer	Fanout Buffer
Ratio - Input:Output	1:4	1:4	1:4	1:4	1:4
Frequency - Max	160 MHz	160 MHz	180 MHz	180 MHz	180 MHz
Input Logic	CMOS	CMOS	LVCMOS, LVTTL	LVCMOS, LVTTL	LVCMOS, LVTTL
Output Logic	CMOS	CMOS	LVCMOS, LVTTL	LVCMOS, LVTTL	LVCMOS, LVTTL
Voltage - Supply	3V ~ 5.5V	3V ~ 5.5V	3V ~ 5.5V	3V ~ 5.5V	1.4V ~ 2.7V
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

551MLFT (Renesas Electronics) is the primary direct substitute for ICS551MT. This part maintains identical electrical specifications (160 MHz maximum frequency, 3V to 5.5V supply, CMOS logic) and package geometry. The 551MLFT is currently in active production status with higher inventory availability (8361 units) compared to the obsolete ICS551MT. The part achieves ROHS3 compliance, addressing environmental regulatory requirements where applicable.

NB3N551DG and NB3N551DR2G (onsemi) are functionally compatible alternatives with enhanced specifications. Both parts support 180 MHz maximum frequency (20 MHz above ICS551MT specification), extended operating temperature range (-40°C to 85°C versus 0°C to 70°C), and LVCMOS/LVTTL input-output compatibility. These parts are actively produced and ROHS3 compliant. The NB3N551DR2G is supplied in Tape & Reel packaging (2269 units available), while NB3N551DG is supplied in Tube packaging (1105 units available).

PI6C10804WE (Diodes Incorporated) is a functional equivalent with a critical supply voltage limitation. This part operates at 1.4V to 2.7V, which does not overlap with the ICS551MT supply range of 3V to 5.5V. The PI6C10804WE is discontinued at DiGi Electronics and is not recommended for new designs requiring 3V to 5.5V operation. This part is listed for reference only and is not a practical substitute for standard ICS551MT applications.

Frequently Asked Questions (FAQ)

Q: Can 551MLFT directly replace ICS551MT without circuit modifications?

A: Yes. The 551MLFT maintains identical electrical specifications, package footprint, and pinout. No circuit modifications are required for direct substitution on existing PCB designs.

Q: What is the primary advantage of using NB3N551DG or NB3N551DR2G over 551MLFT?

A: The onsemi parts (NB3N551DG and NB3N551DR2G) provide 180 MHz maximum frequency capability and extended operating temperature range (-40°C to 85°C). These specifications exceed ICS551MT requirements and provide design margin for applications requiring higher frequency performance or wider temperature operation.

Q: Is PI6C10804WE suitable as a substitute for ICS551MT?

A: No. The PI6C10804WE operates at 1.4V to 2.7V supply voltage, which is incompatible with ICS551MT's 3V to 5.5V requirement. This part cannot be used as a direct substitute in systems designed for standard 3.3V or 5V logic levels.

Q: What packaging options are available for substitute parts?

A: 551MLFT is available in Cut Tape (CT) and Digi-Reel packaging. NB3N551DG is supplied in Tube packaging. NB3N551DR2G is supplied in Tape & Reel (TR) packaging. All substitute parts use identical 8-SOIC (0.154", 3.90mm Width) surface mount package geometry.

Q: Are all substitute parts RoHS compliant?

A: The 551MLFT, NB3N551DG, NB3N551DR2G, and PI6C10804WE are all ROHS3 compliant. The original ICS551MT is RoHS non-compliant. Substitution with any of these parts addresses RoHS compliance requirements for new production.

Q: What is the moisture sensitivity level (MSL) for substitute parts?

A: All substitute parts carry MSL rating of 1 (Unlimited), matching the ICS551MT specification. This indicates minimal moisture sensitivity and standard handling requirements.

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