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

Renesas 49FCT20805QGI8

Name: 49FCT20805QGI8
Brand: Renesas
SKU: 49FCT20805QGI8
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 49FCT20805QGI8

Manufacturer:: Renesas

Category:: Clock Buffers, Drivers

Package:: 20-SSOP (0.154", 3.90mm Width)

Datasheet:: 49FCT20805QGI8.pdf

Description:: IC CLK BUFFER 1:5 166MHZ 20QSOP

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Product details

Overview

49FCT20805QGI8 from Renesas Electronics is a 2.5V CMOS dual 1-to-5 clock driver with two independent output banks (OA1–OA5 and OB1–OB5), each featuring individual 3-state enable control (OEA/OEB), a dedicated monitor output (MON), and guaranteed low skew (<200 ps max), propagation delay (<2.5 ns max), and duty cycle distortion (<270 ps max). It operates up to 166 MHz in industrial temperature range (–40°C to +85°C) and supports high-fidelity clock distribution in synchronous memory systems.

For engineers reviewing the 49FCT20805QGI8 datasheet, 49FCT20805QGI8 pinout, 49FCT20805QGI8 application, or 49FCT20805QGI8 equivalent, key selection criteria include output bank independence, MON output functional equivalence to OA/OB outputs, SSOP/QSOP package compatibility, TTL-compatible I/O, and verified performance at 133–166 MHz under CL = 15 pF load.

Technical Context

The 49FCT20805QGI8 implements two fully isolated clock distribution paths, each accepting one input (INA/INB) and driving five CMOS outputs plus a shared MON output identical in timing and drive strength to OA/OB pins. All outputs are buffered with matched rise/fall times (≤1.25 ns) and support simultaneous switching under 15 pF load.

Its architecture enables precise skew control via matched internal routing and process-compensated drivers; part-to-part skew is specified at ≤550 ps, and pulse skew remains ≤270 ps across temperature and voltage. The device uses advanced CMOS with VCC = 2.5 V ±0.2 V and features low-input capacitance (CIN ≤ 4 pF) for minimal loading on upstream clock sources.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Supply	2.5 V ±0.2 V - defines strict rail tolerance for stable low-voltage clock integrity and noise margin
Max Frequency	166 MHz - supports DDR2/DDR3 address/control clocking and high-speed bus synchronization
Output Skew (tSK(O))	<200 ps max - ensures sub-nanosecond alignment across all 10 outputs within same device
Propagation Delay	<2.5 ns max (tPLH/tPHL) - enables tight timing budgets in <6 ns clock cycles
Duty Cycle Distortion	<270 ps max - preserves 50% duty cycle critical for double-data-rate interfaces
Input Capacitance	≤4 pF - minimizes loading on PLL/VCO or crystal oscillator outputs
Output Drive	±90 mA (IOH/IOL) - drives 50 Ω transmission lines or multiple CMOS inputs without external buffers

Pinout & Package

49FCT20805QGI8 is packaged in a 20-pin QSOP (Quarter-size Small Outline IC) with 0.65 mm pitch, JEDEC MO-137 compliant, and rated for industrial temperature operation (–40°C to +85°C).

Pin/Terminal	Circuit Role	Design Meaning
INA, INB	CMOS/TTL-compatible clock inputs	Accept single-ended clocks; VIH ≥ 1.7 V, VIL ≤ 0.7 V; CIN ≤ 4 pF
OEA, OEB	Active-low 3-state output enables	Independent bank control; asserts high-impedance on respective OA or OB outputs
OA1–OA5, OB1–OB5	Buffered clock outputs	Each delivers identical timing (skew ≤200 ps), drive (±90 mA), and voltage swing (VOH ≥1.7 V)
MON	Monitor output	Functionally identical to OA/OB outputs; used for diagnostics or PLL feedback without affecting main banks
VCCA, VCCB, GNDQ, GNDA, GNDB	Power and ground terminals	Separate VCC/GND per bank (VCCA/GNDA, VCCB/GNDB) + quad ground (GNDQ) for noise isolation

Key Features

Feature	Design Value
Dual independent 1:5 fanout banks	Enables separate clock domains (e.g., CPU + memory interface) with no cross-bank timing coupling
"Heartbeat" MON output	Provides real-time diagnostic copy of either bank's output without adding load or altering timing
Guaranteed low skew & distortion	Ensures setup/hold compliance in multi-sink synchronous systems (e.g., SDRAM controllers)
TTL-compatible I/O	Interoperates directly with legacy logic families without level-shifting circuitry
Low dynamic power (ICCD = 65 μA/MHz per output)	Reduces total supply current in high-frequency applications (e.g., 166 MHz × 10 outputs ≈ 115 mA)

Applications

Memory Interface Clock Distribution	Synchronous Bus Timing
Use Scenario: Distributing a single system clock to multiple DDR2 SDRAM chips with matched trace lengths. IC Role / Device Role / Timing Role: Dual-bank clock driver providing phase-aligned OA and OB outputs to separate memory ranks while MON feeds PLL feedback. Use Value: Sub-200 ps intra-device skew maintains tAC/tOH margins across 10+ outputs at 166 MHz.	Use Scenario: Driving address/control signals across a 32-bit parallel bus in an industrial PLC backplane. IC Role / Device Role / Timing Role: Fanout buffer isolating microcontroller clock outputs from capacitive bus loading and crosstalk. Use Value: Low CIN (≤4 pF) prevents clock jitter; TTL-compatible outputs interface directly with bus transceivers.
PLL Reference Distribution	Test Equipment Clock Tree
Use Scenario: Delivering a clean 100 MHz reference from a PLL to ADCs, DACs, and FPGA fabric clocks. IC Role / Device Role / Timing Role: Low-distortion clock repeater with MON output verifying signal integrity before distribution. Use Value: ≤270 ps duty cycle distortion preserves sampling window symmetry in high-resolution converters.	Use Scenario: Generating synchronized trigger and sample clocks across multiple channels in automated test equipment. IC Role / Device Role / Timing Role: Precision clock splitter ensuring deterministic inter-channel timing alignment. Use Value: Part-to-part skew ≤550 ps enables channel calibration without per-unit compensation.

Memory Interface Clock Distribution

Synchronous Bus Timing

Use Scenario: Distributing a single system clock to multiple DDR2 SDRAM chips with matched trace lengths.

IC Role / Device Role / Timing Role: Dual-bank clock driver providing phase-aligned OA and OB outputs to separate memory ranks while MON feeds PLL feedback.

Use Value: Sub-200 ps intra-device skew maintains tAC/tOH margins across 10+ outputs at 166 MHz.

Use Scenario: Driving address/control signals across a 32-bit parallel bus in an industrial PLC backplane.

IC Role / Device Role / Timing Role: Fanout buffer isolating microcontroller clock outputs from capacitive bus loading and crosstalk.

Use Value: Low CIN (≤4 pF) prevents clock jitter; TTL-compatible outputs interface directly with bus transceivers.

PLL Reference Distribution

Test Equipment Clock Tree

Use Scenario: Delivering a clean 100 MHz reference from a PLL to ADCs, DACs, and FPGA fabric clocks.

IC Role / Device Role / Timing Role: Low-distortion clock repeater with MON output verifying signal integrity before distribution.

Use Value: ≤270 ps duty cycle distortion preserves sampling window symmetry in high-resolution converters.

Use Scenario: Generating synchronized trigger and sample clocks across multiple channels in automated test equipment.

IC Role / Device Role / Timing Role: Precision clock splitter ensuring deterministic inter-channel timing alignment.

Use Value: Part-to-part skew ≤550 ps enables channel calibration without per-unit compensation.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ICS8302AMLF	Single 1:10 bank, no MON output, 3.3 V only, tSK(O) = 350 ps	Lacks dual-bank isolation and monitor capability; suited for simpler unidirectional fanout	Select when only one clock domain exists and MON diagnostics are unnecessary
PI6C20400LEX	2.5 V/3.3 V dual-supply, LVDS outputs, no TTL compatibility, tSK(O) = 150 ps	Requires level translation for TTL systems; optimized for low-noise differential signaling	Select for EMI-sensitive environments where LVDS routing is already implemented

Compared with ICS8302AMLF and PI6C20400LEX, the 49FCT20805QGI8 uniquely combines dual independent banks, TTL compatibility, and a functional MON output-making it optimal for industrial systems requiring robust, debuggable, and mixed-voltage clock distribution without redesigning signal integrity paths.

Availability

49FCT20805QGI8 is available at Aetrix Electronics and suitable for memory interface clock distribution, synchronous bus timing, and PLL reference distribution requiring stable component supply, long-term industrial temperature support, and verified skew performance.

Supply support for 49FCT20805QGI8 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

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and timing solutions for automotive, industrial, and infrastructure markets.

The 49FCT20805QGI8 belongs to Renesas' legacy IDT timing portfolio, designed specifically for high-reliability, low-skew clock distribution in industrial computing and memory subsystems where signal fidelity and thermal stability are non-negotiable.

FAQ

What is the operating voltage range for the 49FCT20805QGI8?

The 49FCT20805QGI8 operates strictly at VCC = 2.5 V ±0.2 V (i.e., 2.3 V to 2.7 V). It is not rated for 3.3 V or 5 V operation. Exceeding this range risks violating absolute maximum ratings (VCC ≤ +4.6 V), and functionality outside 2.3–2.7 V is not guaranteed per datasheet specifications. Always regulate to 2.5 V with ≤±0.2 V tolerance for compliant operation of the 49FCT20805QGI8.

Does the MON output of the 49FCT20805QGI8 have the same electrical characteristics as the OA/OB outputs?

Yes-the MON output of the 49FCT20805QGI8 is electrically identical to OA and OB outputs: same propagation delay, skew, drive strength (±90 mA), VOH/VOL levels, and rise/fall times. The datasheet explicitly states "MON output is identical to all other outputs and complies with the output specifications," confirming its use as a true functional replica for diagnostics or PLL feedback without degrading timing integrity of the 49FCT20805QGI8.

Can the 49FCT20805QGI8 drive 50 Ω transmission lines directly?

Yes-the 49FCT20805QGI8 can drive 50 Ω loads directly. Its output drive capability (IODH = –90 mA, IODL = 100 mA at VO = 1.25 V) supports termination into 50 Ω with proper VTT referencing. Rise/fall times (≤1.25 ns) and low output capacitance (COUT ≤ 6 pF) ensure clean edge integrity on controlled-impedance traces, making the 49FCT20805QGI8 suitable for point-to-point clock distribution without external buffers.

What is the meaning of "dual 1-to-5" in the 49FCT20805QGI8 description?

"Dual 1-to-5" means the 49FCT20805QGI8 contains two completely independent clock distribution banks: Bank A accepts INA and drives OA1–OA5; Bank B accepts INB and drives OB1–OB5. Each bank has its own 3-state enable (OEA/OEB), allowing selective activation. This architecture supports two separate clock domains-e.g., core logic and peripheral interface-with no shared timing path, a defining feature of the 49FCT20805QGI8.

Is the 49FCT20805QGI8 pin-compatible with other members of the FCT20805 family?

Yes-the 49FCT20805QGI8 shares identical pinout and function mapping with all variants in the IDT49FCT20805 family (e.g., 49FCT20805PYI8, 49FCT20805QGI), differing only in package type (QSOP vs. SSOP) and marking. Pin assignments-including INA, INB, OEA, OEB, OA1–OA5, OB1–OB5, MON, and power/ground-are fully consistent across the family, enabling drop-in replacement between 49FCT20805QGI8 and other qualified variants.

49FCT20805QGI8 Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Series:: 49FCT

Package/Case:: 20-SSOP (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Type:: Fanout Buffer (Distribution)

Number of Circuits:: 2

Ratio - Input:Output:: 1:5

Differential - Input:Output:: No/No

Input:: CMOS, LVTTL

Output:: CMOS, LVTTL

Frequency - Max:: 166 MHz

Voltage - Supply:: 2.3V ~ 2.7V

Operating Temperature:: -40°C ~ 85°C

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

Supplier Device Package:: 20-QSOP

49FCT20805QGI8 FAQ

1.How can I place an order for 49FCT20805QGI8 through Aetrix?

Please submit a Request for Quotation (RFQ) for 49FCT20805QGI8 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 49FCT20805QGI8 reliable?

The price and inventory of 49FCT20805QGI8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 49FCT20805QGI8 is usually 5 days.

3.What payment methods are accepted for 49FCT20805QGI8?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 49FCT20805QGI8 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 49FCT20805QGI8?

49FCT20805QGI8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 49FCT20805QGI8 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 49FCT20805QGI8?

For technical support, including 49FCT20805QGI8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 49FCT20805QGI8 requirements.

6.How does Aetrix verify that 49FCT20805QGI8 is sourced from the original manufacturer or authorized distributors?

All 49FCT20805QGI8 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 49FCT20805QGI8 meets industry standards.

7.What is the process for return or replacement of 49FCT20805QGI8?

All 49FCT20805QGI8 units undergo pre-shipment inspection (PSI). If there is an issue with 49FCT20805QGI8, 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 49FCT20805QGI8 part is unused and in its original packaging.

Return procedure for 49FCT20805QGI8:

1.Submit a request within 90 days.

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

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