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

Texas Instruments CDC319DBR

Name: CDC319DBR
Brand: Texas Instruments
SKU: CDC319DBR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: CDC319DBR

Manufacturer:: Texas Instruments

Category:: Clock Buffers, Drivers

Package:: 28-SSOP (0.209", 5.30mm Width)

Datasheet:: CDC319DBR.pdf

Description:: IC CLK BUFFER 1:10 100MHZ 28SSOP

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Product details

Overview

CDC319DBR from Texas Instruments is a high-speed, low-skew 1-to-10 clock buffer IC designed for SDRAM clock distribution in memory subsystems. It operates at 3.3 V, delivers <250 ps output skew and <500 ps pulse skew, supports up to two unbuffered SDRAM DIMMs, and integrates an I²C interface for per-output enable control.

For engineers reviewing the CDC319DBR datasheet, CDC319DBR pinout, CDC319DBR application, or CDC319DBR equivalent, key selection criteria include I²C-configurable output enables, 28-pin SSOP (DB) package compatibility, SDRAM timing compliance, and 0°C to 70°C industrial temperature operation.

Technical Context

The CDC319DBR implements a synchronous clock fanout architecture with distributed V_CC/GND pins to minimize switching noise. Its I²C slave interface operates at 100 kHz, uses internally pulled-up SDATA/SCLOCK lines (140 kΩ), and accesses three write-only 8-bit registers for granular output control.

All 10 outputs are grouped as four 1Y/2Y outputs (pins 2–3, 6–7, 22–23, 26–27) and two 3Y feedback outputs (pins 11, 18), each individually controllable via I²C register bits. The OE input provides global 3-state control with internal pullup.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	3.3 V ±3.5% - matches JEDEC-compliant SDRAM core voltage rails
Output Skew (t_sk(o))	<250 ps - ensures tight phase alignment across all 10 outputs for multi-DIMM synchronization
Pulse Skew (t_sk(p))	<500 ps - maintains clean clock edges critical for DDR timing margins
I²C Interface Speed	100 kHz standard mode - compatible with legacy microcontroller I²C peripherals without rate negotiation
Operating Temperature	0°C to 70°C - validated for commercial-grade embedded memory controllers and baseboard management
Max Clock Frequency	140 MHz at 15 pF load - supports high-speed SDRAM applications including PC133 and early DDR
ESD Protection	>2000 V HBM - meets MIL-STD-883 Method 3015 for board-level handling robustness

Pinout & Package

Packaged in a 28-pin Shrink Small Outline Package (SSOP-DB), the CDC319DBR features distributed power/ground pins (7×V_CC, 7×GND) to suppress simultaneous switching noise in high-frequency clock distribution networks.

Pin/Terminal	Circuit Role	Design Meaning
A (Pin 9)	Clock Input	Single 3.3-V CMOS clock source driving all 10 buffered outputs
1Y0–1Y3 (Pins 2,3,6,7)	SDRAM Byte 0 Outputs	Four dedicated clock outputs for first SDRAM byte lane (e.g., DQ0–DQ7)
2Y0–2Y3 (Pins 22,23,26,27)	SDRAM Byte 1 Outputs	Four dedicated clock outputs for second SDRAM byte lane (e.g., DQ8–DQ15)
3Y0–3Y1 (Pins 11,18)	PLL Feedback Outputs	Two low-jitter outputs for external PLL reference or feedback loop closure
OE (Pin 20)	Global Output Enable	Active-high signal placing all outputs in high-impedance state for system test/debug
SDATA (Pin 14)	I²C Bidirectional Data	5-V-tolerant, internally pulled-up I²C data line supporting standard-mode protocol
SCLOCK (Pin 15)	I²C Serial Clock	5-V-tolerant, internally pulled-up I²C clock input synchronized to master controller

Key Features

Feature	Design Value
I²C-per-output enable control	Three 8-bit write-only registers allow independent disable of any Y output to low state-enabling dynamic power gating per memory bank
Distributed V_CC/GND layout	Seven V_CC and seven GND pins minimize ground bounce and supply droop during simultaneous edge transitions
5-V-tolerant I²C interface	SDATA/SCLOCK accept up to 6.5 V inputs-enables direct interfacing with 5-V microcontrollers without level shifters
Integrated pullup resistors	140 kΩ internal pullups on SDATA/SCLOCK/OE eliminate external components and reduce BOM count
3-state global OE	Hardware-controlled tri-state capability simplifies in-system testing and allows shared bus topology during debug

Applications

SDRAM Memory Subsystem	Industrial PLC Backplane
Use Scenario: Distributing a single system clock to multiple SDRAM chips across dual DIMM slots in a desktop or embedded mainboard. IC Role / Device Role / Timing Role: Low-skew clock fanout buffer with I²C-configurable outputs managing byte-lane-specific enable states. Use Value: Enables precise inter-DIMM skew control (<250 ps) and selective clock gating to meet PC133 t_AC and t_SKEW specifications.	Use Scenario: Providing synchronized clock signals to multiple I/O modules on a ruggedized programmable logic controller backplane. IC Role / Device Role / Timing Role: Industrial-grade clock repeater with 0°C to 70°C operation and ESD-hardened I²C interface for remote configuration. Use Value: Delivers stable 140-MHz clock distribution under electrically noisy factory environments while allowing runtime reconfiguration via fieldbus-connected MCU.
DDR SDRAM Reference Design	Test Equipment Clock Tree
Use Scenario: Generating matched clock pairs for DDR SDRAM data strobes and address/control signals in early DDR reference platforms. IC Role / Device Role / Timing Role: Dual-bank clock driver supplying 1Y/2Y outputs to separate memory banks and 3Y outputs for PLL feedback. Use Value: Supports 140-MHz operation at 15-pF load-meeting DDR-266 timing budgets while enabling closed-loop jitter reduction via 3Y feedback path.	Use Scenario: Building a modular, reconfigurable clock distribution network in automated test equipment requiring per-channel enable/disable. IC Role / Device Role / Timing Role: Programmable clock buffer with I²C register access enabling software-defined channel activation during test sequence execution. Use Value: Eliminates manual jumpering or FPGA-based clock gating-reducing test setup time and improving channel-to-channel skew repeatability across production units.

SDRAM Memory Subsystem

Industrial PLC Backplane

Use Scenario: Distributing a single system clock to multiple SDRAM chips across dual DIMM slots in a desktop or embedded mainboard.

IC Role / Device Role / Timing Role: Low-skew clock fanout buffer with I²C-configurable outputs managing byte-lane-specific enable states.

Use Value: Enables precise inter-DIMM skew control (<250 ps) and selective clock gating to meet PC133 t_AC and t_SKEW specifications.

Use Scenario: Providing synchronized clock signals to multiple I/O modules on a ruggedized programmable logic controller backplane.

IC Role / Device Role / Timing Role: Industrial-grade clock repeater with 0°C to 70°C operation and ESD-hardened I²C interface for remote configuration.

Use Value: Delivers stable 140-MHz clock distribution under electrically noisy factory environments while allowing runtime reconfiguration via fieldbus-connected MCU.

DDR SDRAM Reference Design

Test Equipment Clock Tree

Use Scenario: Generating matched clock pairs for DDR SDRAM data strobes and address/control signals in early DDR reference platforms.

IC Role / Device Role / Timing Role: Dual-bank clock driver supplying 1Y/2Y outputs to separate memory banks and 3Y outputs for PLL feedback.

Use Value: Supports 140-MHz operation at 15-pF load-meeting DDR-266 timing budgets while enabling closed-loop jitter reduction via 3Y feedback path.

Use Scenario: Building a modular, reconfigurable clock distribution network in automated test equipment requiring per-channel enable/disable.

IC Role / Device Role / Timing Role: Programmable clock buffer with I²C register access enabling software-defined channel activation during test sequence execution.

Use Value: Eliminates manual jumpering or FPGA-based clock gating-reducing test setup time and improving channel-to-channel skew repeatability across production units.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
CDCLVC1107PW	LVCMOS 1-to-10 buffer with no I²C interface; fixed-enable outputs; 3.3-V only; 16-pin TSSOP	Lacks per-output enable control; requires external logic for dynamic gating; smaller footprint but no serial configurability	Select when I²C control is unnecessary and board space is constrained
PI6C20400LEX	PCI Express Gen1 clock buffer with 1-to-4 fanout; integrated spread-spectrum; 3.3-V; 32-pin QFN	Designed for PCIe clock trees-not SDRAM; lacks I²C register space; higher integration but incompatible output grouping	Select for PCI Express timing systems where SDRAM buffering is not required

Compared with CDCLVC1107PW and PI6C20400LEX, the CDC319DBR uniquely combines I²C-configurable per-output enables, SDRAM-optimized low skew, and 28-pin SSOP packaging-making it the only option supporting dynamic, software-controlled clock gating in legacy SDRAM memory subsystems.

Availability

CDC319DBR is available at Aetrix Electronics and suitable for SDRAM memory subsystems, industrial PLC backplanes, DDR reference designs, and test equipment clock trees requiring stable component supply and long-term obsolescence management.

Supply support for CDC319DBR 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies with over 90 years of innovation in precision timing and power management.

The CDC319DBR belongs to TI's clock distribution product line, engineered specifically for high-fidelity SDRAM clock buffering in commercial computing and industrial control systems where deterministic skew and I²C configurability are mandatory.

FAQ

What is the maximum operating frequency supported by the CDC319DBR?

The CDC319DBR supports up to 140 MHz at a 15-pF capacitive load per output, as specified in Figure 4 of the SCAS590A datasheet. At higher loads (e.g., 30 pF), the maximum usable frequency drops to 100 MHz. This performance enables compliance with PC133 SDRAM and early DDR-266 timing requirements when used with properly terminated transmission lines.

Does the CDC319DBR require external pullup resistors on its I²C lines?

No, the CDC319DBR integrates 140-kΩ pullup resistors on both SDATA (Pin 14) and SCLOCK (Pin 15), eliminating the need for external components. These internal pullups are sufficient for standard-mode I²C operation at 100 kHz and support direct connection to 3.3-V or 5-V microcontrollers without level-shifting circuitry.

How many SDRAM DIMMs can the CDC319DBR drive simultaneously?

The CDC319DBR is explicitly characterized to support up to two unbuffered SDRAM DIMMs, as stated in the device description and functional overview. Its 10-output architecture-grouped as eight byte-lane clocks (1Y0–1Y3, 2Y0–2Y3) plus two feedback outputs (3Y0–3Y1)-is optimized for dual-DIMM configurations with independent enable control per lane.

What is the function of the 3Y0 and 3Y1 outputs on the CDC319DBR?

The 3Y0 (Pin 11) and 3Y1 (Pin 18) outputs on the CDC319DBR are designated as 3.3-V clock outputs for feedback control of external phase-locked loops (PLLs). Unlike the 1Y/2Y outputs, they are not assigned to specific SDRAM byte lanes but provide low-jitter references to stabilize system clock synthesis in architectures requiring closed-loop timing control.

Is the CDC319DBR pin-compatible with other devices in the CDC319 family?

Yes, the CDC319DBR shares identical pinout and electrical characteristics with CDC319DB, CDC319DB.B, and CDC319DBR.B-all packaged in the 28-pin SSOP (DB) format. Differences are limited to packaging (tube vs. tape-and-reel) and marking; no functional or pinout variation exists across these orderable variants of the CDC319DBR.

CDC319DBR Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 28-SSOP (0.209", 5.30mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Type:: Fanout Buffer (Distribution), Data

Number of Circuits:: 1

Ratio - Input:Output:: 1:10

Differential - Input:Output:: No/No

Input:: LVTTL

Output:: LVTTL, TTL

Frequency - Max:: 100 MHz

Voltage - Supply:: 3.135V ~ 3.465V

Operating Temperature:: 0°C ~ 70°C

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

Supplier Device Package:: 28-SSOP

CDC319DBR FAQ

1.How can I place an order for CDC319DBR through Aetrix?

Please submit a Request for Quotation (RFQ) for CDC319DBR 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 CDC319DBR reliable?

The price and inventory of CDC319DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CDC319DBR is usually 5 days.

3.What payment methods are accepted for CDC319DBR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CDC319DBR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for CDC319DBR?

CDC319DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your CDC319DBR 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 CDC319DBR?

For technical support, including CDC319DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CDC319DBR requirements.

6.How does Aetrix verify that CDC319DBR is sourced from the original manufacturer or authorized distributors?

All CDC319DBR 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 CDC319DBR meets industry standards.

7.What is the process for return or replacement of CDC319DBR?

All CDC319DBR units undergo pre-shipment inspection (PSI). If there is an issue with CDC319DBR, 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 CDC319DBR part is unused and in its original packaging.

Return procedure for CDC319DBR:

1.Submit a request within 90 days.

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

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