Infineon Technologies CY26049ZXC-36T

Overview

CY26049ZXC-36 from Cypress Semiconductor is a FailSafe™ PacketClock™ global communications clock generator featuring a fully integrated PLL, DCXO-based failover architecture, and three programmable outputs (CLK, CLK/2, 8K). It delivers zero-ppm synthesis error for T1/DS1 (1.544 MHz), E1 (2.048 MHz), OC-3 (155.52 MHz), and other telecom standards, operating from a 18.432-MHz pullable crystal with 3.3V ±5% supply. Used in telecom line cards requiring continuous clocking during reference loss.

For engineers reviewing the CY26049ZXC-36 datasheet, CY26049ZXC-36 pinout, CY26049ZXC-36 application, or CY26049ZXC-36 equivalent, key selection criteria include FailSafe status reporting via SAFE pin, buffer-mode jitter attenuation (≤250 ps peak-to-peak jitter >5 MHz), industrial-grade temperature support (–40°C to +85°C), and compatibility with Ecliptek ECX-5761/5762 crystals.

Technical Context

The CY26049ZXC-36 implements a dual-source clock architecture where the DCXO serves as the primary timing source, synchronized to an external ICLK reference (8 kHz or 10–60 MHz) only when within ±250 ppm lock range. Its FailSafe control circuit asserts SAFE high during synchronization and maintains last-known frequency/phase upon reference failure.

In buffer mode (FS3:FS0 = 1110 or 1111), it functions as a jitter attenuator: input clock jitter is filtered by the PLL, producing low-jitter outputs (RMS period jitter ≤50 ps for >5 MHz outputs). Output frequencies are selected via four FS pins, supporting 16 configurations per Table 1, including T1, E1, T3, E3, and OC-3 rates.

Key Specifications

Pinout & Package

Package: 16-pin TSSOP (JEDEC MO-153), 6.5 mm × 4.4 mm body, 1.1 mm max height, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

CY26049ZXC-36 has two verified drop-in alternatives for design flexibility and supply continuity.

Compared with Si5338A-B-GM and ICS8430I-01T, CY26049ZXC-36 uniquely combines autonomous FailSafe status reporting, zero-ppm telecom synthesis, and integrated DCXO-making it irreplaceable in applications requiring guaranteed holdover without host processor intervention.

Availability

CY26049ZXC-36 is available at Aetrix Electronics and suitable for telecom line cards, SONET/SDH framer interfaces, and wireless baseband units requiring stable component supply, long-lifecycle availability, and lead-free compliance.

Supply support for CY26049ZXC-36 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) is a fabless semiconductor company specializing in high-performance timing, memory, and programmable solutions for communications and industrial markets.

The CY26049 product line was designed specifically for carrier-grade telecommunications infrastructure requiring uninterrupted clocking, with FailSafe™ architecture addressing NEBS Level 3 reliability requirements.

FAQ

What is the function of the SAFE pin on CY26049ZXC-36?

The SAFE pin is an open-drain output that signals PLL lock status: driven high when the ICLK reference is within ±250 ppm of nominal and phase-aligned with the DCXO; pulled low when reference is lost or out-of-range. It directly enables hardware-level failover decisions without microcontroller polling.

Can CY26049ZXC-36 operate without an external crystal?

No. The device requires an 18.432-MHz pullable AT-cut crystal connected between XIN and XOUT pins to establish its DCXO baseline frequency. No internal oscillator exists; crystal specifications (CL = 14 pF, ESR ≤ 25 Ω) are mandatory for stable operation and FailSafe functionality.

How does buffer mode differ from external mode in CY26049ZXC-36?

In buffer mode (FS3:FS0 = 1110 or 1111), the PLL uses ICLK directly as the output source after jitter filtering-CLK = ICLK or 2×ICLK, with CLK/2 = ICLK/2. External mode uses the DCXO as master source, generating synthesized frequencies (e.g., 1.544 MHz) independent of ICLK value.

Is CY26049ZXC-36 compatible with industrial temperature range designs?

Yes. While CY26049ZXC-36 is specified for 0°C to +70°C (commercial), its underlying silicon and DCXO architecture are qualified for –40°C to +85°C operation. For industrial use, select CY26049ZXI-36T, which shares identical functionality and pinout but is tested and warranted across the extended range.