Infineon Technologies CY29973AXIT

Overview

CY29973AXIT from Cypress Semiconductor is a 3.3V, 125-MHz multi-output zero-delay buffer IC with integrated PLL, delivering 12 configurable clock outputs and one dedicated feedback output (FB_OUT) for high-performance microprocessor clock trees. It supports dual reference inputs (PECL or single-ended TCLK), offers <350 ps max output-to-output skew, and operates across -40°C to +85°C in industrial applications requiring precise timing synchronization.

For engineers reviewing the CY29973AXIT datasheet, CY29973AXIT pinout, CY29973AXIT application, or CY29973AXIT equivalent, this device is selected for low-jitter, glitch-free frequency transitions, spread-spectrum compatibility, and dynamic bank-level output enable/disable control in nested clock distribution systems.

Technical Context

The CY29973AXIT integrates a voltage-controlled oscillator (VCO) locked between 200–480 MHz, with programmable feedback division (via FB_SEL[2:0]) and VCO_SEL to maintain stability at lower reference frequencies. Its phase detector compares FB_IN to the reference, enabling zero-delay operation when FB_OUT is looped back.

Three independent output banks (QA[3:0], QB[3:0], QC[3:0]) each support four selectable divide ratios (e.g., /4, /6, /8, /12), while SYNC provides a system-synchronization pulse aligned to coincident rising edges of QA and QC clocks - independent of their integer or non-integer frequency relationships.

Key Specifications

Pinout & Package

52-pin TQFP (10 × 10 × 1.0 mm), lead-free, industrial temperature grade (-40°C to +85°C). Pin 1 marked by dot; thermal pad exposed on underside per package drawing A52B.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-output zero-delay buffer applications.

Compared with IDT5V9875A and MPC973, the CY29973AXIT uniquely combines 12 configurable outputs, hardware-synced pulse generation, and glitch-free live reconfiguration - making it optimal for next-generation compute and industrial timing architectures demanding both precision and adaptability.

Availability

CY29973AXIT is available at Aetrix Electronics and suitable for high-performance CPU clock distribution, DDR memory interface timing, multi-FPGA synchronization, and industrial PLC real-time control requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CY29973AXIT 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

Cypress Semiconductor (now part of Infineon Technologies) designs high-performance timing, memory, and microcontroller solutions for computing, communications, and industrial markets.

The CY29973 belongs to Cypress's Zero-Delay Buffer product line, engineered specifically for low-skew, multi-output clock synthesis in systems requiring deterministic phase alignment and dynamic reconfiguration without clock glitches.

FAQ

What is the minimum reference input frequency supported by CY29973AXIT?

The minimum reference frequency depends on the selected VCO divider and FB_SEL settings to keep VCO within 200–480 MHz. For example, with FB_SEL=000 (×8) and VCO_SEL=1 (bypassed), minimum reference is 25 MHz (200 MHz ÷ 8). Lower references require VCO_SEL=0 (/2) or higher multiplication factors per Table 1.

Can QC0 and FB_OUT be disabled via the serial interface?

No - QC0 and FB_OUT are excluded from serial freeze control to prevent potential PLL lock loss or system deadlock if erroneous SDATA is loaded. They can only be disabled globally via MR#/OE or by disabling the PLL using PLL_EN.

How does the SYNC output behave when QA and QC frequencies have a non-integer ratio?

SYNC generates a one-cycle low pulse placed one period before the next coincident rising edge of QA and QC, regardless of ratio (e.g., 3:2, 4:3). Its timing is derived from internal edge detection logic, not fixed dividers, ensuring deterministic alignment even for irrational frequency relationships.

Is external termination required for PECL_CLK inputs?

Yes - PECL inputs require 50 Ω termination to VDD/2 (1.65 V) for proper common-mode bias and signal integrity. The datasheet specifies VCMR = VDD–2.0 V to VDD–0.6 V, and mismatched termination causes duty cycle distortion or failed lock.