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

Texas Instruments CDC328ADR

Name: CDC328ADR
Brand: Texas Instruments
SKU: CDC328ADR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: CDC328ADR

Manufacturer:: Texas Instruments

Category:: Clock Buffers, Drivers

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: CDC328ADR.pdf

Description:: IC CLK BUFFER 1:6 100MHZ 16SOIC

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Product details

Overview

CDC328ADR from Texas Instruments is a 1:6 TTL-compatible clock distribution IC with polarity-selectable true/complementary outputs, low output skew (≤1 ns), ±48-mA drive strength, and operation across −40°C to 85°C - deployed in high-speed digital backplanes and FPGA clock trees.

For engineers reviewing the CDC328ADR datasheet, CDC328ADR pinout, CDC328ADR application, or CDC328ADR equivalent, key selection criteria include input clock frequency support up to 100 MHz, SOIC-16 package compatibility, TTL-level I/O voltage thresholds, and skew-critical timing distribution requirements.

Technical Context

The CDC328ADR implements a single-input, six-output clock buffer using EPIC-II^B BiCMOS technology to achieve low propagation delay (1.5–5 ns) and minimal pulse skew (≤1 ns). It supports independent polarity control per output pair via four T/C inputs.

Each output stage delivers ±48 mA drive capability into TTL loads, while distributed V_CC/GND pins reduce switching noise. The device requires no external biasing and operates strictly within 4.75 V–5.25 V supply range.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Clock Frequency	Up to 100 MHz - supports high-speed synchronous logic domains including PCI and early DSP systems.
Output Skew (tsk(o))	≤1 ns - ensures deterministic phase alignment across all six outputs for multi-sink clock fanout.
Drive Strength	−48 mA IOH / 48 mA IOL - directly drives multiple TTL inputs without external buffers.
Propagation Delay	1.5–5 ns (tPLH/tPHL) - enables sub-5-ns timing budget allocation in critical clock paths.
Supply Voltage Range	4.75 V–5.25 V - compatible with standard 5-V TTL/CMOS logic rails and regulated 5-V supplies.
Operating Temperature	−40°C to 85°C - qualified for industrial-grade embedded and communications equipment environments.

Pinout & Package

Package: SOIC-16 (D package), 7.5 mm × 10.3 mm body, 1.27 mm pitch, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Pin/Terminal	Circuit Role	Design Meaning
1	GND	Ground reference for output stages and internal logic; one of three dedicated GND pins for noise reduction.
2	1Y2	Complementary output of first pair (inverted relative to 1Y1 when 1T/C = H).
3	2Y1	True output of second pair; polarity determined by 2T/C state.
4	GND	Second ground pin - decouples switching transients between output banks.
5	2Y2	Complementary output of second pair; synchronized with 2Y1 under shared 2T/C control.
6	3Y	True output of third pair; polarity fixed unless modified by 3T/C (active-low control).
7	GND	Third ground pin - isolates power delivery to final output group.
8	4Y	True output of fourth pair; driven from same internal node as A but with configurable polarity.
9	1Y1	True output of first pair; primary buffered replica of input A with minimal delay.
10	1T/C	Polarity control for outputs 1Y1/1Y2 - L = true/complementary, H = complementary/true.
11	V_CC	Main 5-V supply; one of two V_CC pins placed adjacent to output clusters for low-impedance routing.
12	2T/C	Polarity control for outputs 2Y1/2Y2 - independent of other T/C inputs.
13	A	Primary clock input - accepts TTL-compatible signals; internally buffered and distributed to all outputs.
14	V_CC	Secondary V_CC pin - reduces IR drop and improves PSRR for upper output bank.
15	3T/C	Polarity control for output 3Y - active-low; determines inversion state of third output.
16	4T/C	Polarity control for output 4Y - active-low; enables independent phase selection for final output.

Key Features

Feature	Design Value
Low Output Skew	≤1 ns between any Y output - maintains tight timing margins in multi-FPGA or ASIC clock trees.
TTL-Compatible I/O	VIH = 2 V, VIL = 0.8 V, VOH ≥ 2 V @ −48 mA - interoperates directly with legacy 5-V logic families without level shifters.
Per-Pair Polarity Control	Four independent T/C inputs (1T/C–4T/C) - enables mixed-phase clock distribution (e.g., differential pairs, latch enable edges).
High-Drive Outputs	±48 mA per output - fans out to ≥10 standard TTL loads or drives transmission lines with minimal termination.
Distributed Power Pins	Three GND + two V_CC pins - suppresses simultaneous switching noise and improves signal integrity in dense PCB layouts.

Applications

Telecom Line Card Timing	FPGA Configuration Clock Distribution
Use Scenario: Distributing a master 50-MHz reference clock to multiple SERDES PHYs and framer ICs on a line card. IC Role / Device Role / Timing Role: Low-skew clock fanout buffer ensuring phase-coherent sampling across parallel data lanes. Use Value: ≤1 ns output skew prevents setup/hold violations at 100-MHz effective data rates across 6 receiver channels.	Use Scenario: Driving configuration clocks to multiple Xilinx Spartan FPGAs during JTAG programming and bitstream loading. IC Role / Device Role / Timing Role: Synchronized clock source enabling concurrent configuration of four FPGA devices. Use Value: Independent T/C controls allow generation of both rising- and falling-edge-triggered clocks for mixed-vendor FPGA chains.
Industrial PLC Backplane Sync	DSP-Based Motor Control Module
Use Scenario: Delivering time-aligned clocks to ADCs, DACs, and microcontrollers across a modular I/O backplane. IC Role / Device Role / Timing Role: Centralized timing hub synchronizing analog and digital subsystems within a single control cycle. Use Value: −40°C to 85°C rating and 4.75–5.25 V supply tolerance ensure reliable operation in unconditioned cabinet environments.	Use Scenario: Providing matched clock phases to dual-TMS320C67x DSPs executing parallel motor control algorithms. IC Role / Device Role / Timing Role: Phase-flexible clock generator supporting interleaved execution and real-time interrupt synchronization. Use Value: Per-output polarity control allows one DSP to use rising-edge sampling while the other uses falling-edge - reducing inter-DSP jitter.

Telecom Line Card Timing

FPGA Configuration Clock Distribution

Use Scenario: Distributing a master 50-MHz reference clock to multiple SERDES PHYs and framer ICs on a line card.

IC Role / Device Role / Timing Role: Low-skew clock fanout buffer ensuring phase-coherent sampling across parallel data lanes.

Use Value: ≤1 ns output skew prevents setup/hold violations at 100-MHz effective data rates across 6 receiver channels.

Use Scenario: Driving configuration clocks to multiple Xilinx Spartan FPGAs during JTAG programming and bitstream loading.

IC Role / Device Role / Timing Role: Synchronized clock source enabling concurrent configuration of four FPGA devices.

Use Value: Independent T/C controls allow generation of both rising- and falling-edge-triggered clocks for mixed-vendor FPGA chains.

Industrial PLC Backplane Sync

DSP-Based Motor Control Module

Use Scenario: Delivering time-aligned clocks to ADCs, DACs, and microcontrollers across a modular I/O backplane.

IC Role / Device Role / Timing Role: Centralized timing hub synchronizing analog and digital subsystems within a single control cycle.

Use Value: −40°C to 85°C rating and 4.75–5.25 V supply tolerance ensure reliable operation in unconditioned cabinet environments.

Use Scenario: Providing matched clock phases to dual-TMS320C67x DSPs executing parallel motor control algorithms.

IC Role / Device Role / Timing Role: Phase-flexible clock generator supporting interleaved execution and real-time interrupt synchronization.

Use Value: Per-output polarity control allows one DSP to use rising-edge sampling while the other uses falling-edge - reducing inter-DSP jitter.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74ACT1094N	8-output, no polarity control, 3.3-V only, CMOS input thresholds.	Lacks T/C flexibility; requires level translation for 5-V systems.	Select when higher fanout count is needed and phase control is unnecessary.
CDC2509DW	9-output, LVCMOS I/O, 3.3-V supply, integrated PLL, no T/C pins.	Supports frequency synthesis but incompatible with TTL signaling and 5-V rails.	Choose for modern low-voltage designs requiring jitter cleanup and multiplication.

Compared with SN74ACT1094N and CDC2509DW, the CDC328ADR uniquely combines 5-V TTL compatibility, per-pair polarity selection, and sub-1-ns skew in a cost-optimized SOIC-16 package - making it irreplaceable in legacy industrial and telecom clock trees requiring precise phase management.

Availability

CDC328ADR is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and FPGA-based prototyping platforms requiring stable component supply and long-term obsolescence management.

Supply support for CDC328ADR 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The CDC328ADR belongs to TI's legacy clock distribution family designed specifically for high-fanout, low-skew 5-V TTL clock buffering in mission-critical digital systems before the widespread adoption of LVDS and differential clocks.

FAQ

What is the maximum input clock frequency supported by the CDC328ADR?

The CDC328ADR supports an input clock frequency up to 100 MHz under recommended operating conditions (V_CC = 4.75 V–5.25 V, T_A = −40°C to 85°C). This specification is validated per the SCAS327B datasheet and applies to all six outputs with guaranteed timing margins and skew performance.

Does the CDC328ADR require external pull-up or pull-down resistors on unused T/C inputs?

Yes - per Note 3 in the SCAS327B datasheet, unused T/C inputs (1T/C–4T/C) must be held statically high or low to prevent floating states that could cause undefined output polarity or increased power consumption. The CDC328ADR does not include internal weak terminations on these control pins.

Can the CDC328ADR operate reliably at 4.5 V supply voltage?

No - the CDC328ADR is specified only for 4.75 V–5.25 V supply operation. At 4.5 V, parameters such as VOH (≥2 V @ −48 mA) and tPLH/tPHL (1.5–5 ns) are not guaranteed, and functionality may degrade or fail. Operation outside the recommended range voids parametric compliance per TI's absolute maximum ratings table.

How many ground pins does the CDC328ADR SOIC-16 package have, and why are they distributed?

The CDC328ADR in SOIC-16 (D package) has three dedicated GND pins (pins 1, 4, and 7), positioned to isolate switching noise between output groups. This distributed grounding reduces simultaneous switching output (SSO) noise and improves output edge fidelity - a design feature explicitly cited in the SCAS327B datasheet to minimize clock jitter in high-drive applications.

Is the CDC328ADR pin-compatible with the CDC328ADRG4 or CDC328AD?

Yes - CDC328ADR, CDC328ADRG4, and CDC328AD share identical SOIC-16 (D package) pinout, electrical specifications, and functional behavior. Differences are limited to packaging format (tape-and-reel vs. tube) and surface finish (NiPdAu vs. matte tin), with no impact on PCB layout or circuit design. All variants use the same CDC328A die and marking "CDC328A".

CDC328ADR Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 16-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Type:: Fanout Buffer (Distribution)

Number of Circuits:: 1

Ratio - Input:Output:: 1:6

Differential - Input:Output:: No/No

Input:: TTL

Output:: TTL

Frequency - Max:: 100 MHz

Voltage - Supply:: 4.75V ~ 5.25V

Operating Temperature:: -40°C ~ 85°C

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

Supplier Device Package:: 16-SOIC

CDC328ADR FAQ

1.How can I place an order for CDC328ADR through Aetrix?

Please submit a Request for Quotation (RFQ) for CDC328ADR 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 CDC328ADR reliable?

The price and inventory of CDC328ADR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CDC328ADR is usually 5 days.

3.What payment methods are accepted for CDC328ADR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CDC328ADR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for CDC328ADR?

CDC328ADR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your CDC328ADR 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 CDC328ADR?

For technical support, including CDC328ADR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CDC328ADR requirements.

6.How does Aetrix verify that CDC328ADR is sourced from the original manufacturer or authorized distributors?

All CDC328ADR 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 CDC328ADR meets industry standards.

7.What is the process for return or replacement of CDC328ADR?

All CDC328ADR units undergo pre-shipment inspection (PSI). If there is an issue with CDC328ADR, 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 CDC328ADR part is unused and in its original packaging.

Return procedure for CDC328ADR:

1.Submit a request within 90 days.

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

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