Infineon Technologies PXB 4221 E V3.4-G

Overview

PXB 4221 E V3.4-G from Infineon Technologies is an Interworking Element (IWE8) IC designed for ATM and AAL5 segmentation/reassembly in multi-E1/T1 line cards, supporting up to 8 E1 or 8 T1 lines with integrated clock recovery, UTOPIA Level 2 interface, and IMA support. It delivers 8× E1/T1 framing, ATM cell delineation with HEC generation/check, CAS-aware structured CES, and fractional PLL-based clock synchronization.

For engineers reviewing the PXB 4221 E V3.4-G datasheet, PXB 4221 E V3.4-G pinout, PXB 4221 E V3.4-G application, or PXB 4221 E V3.4-G equivalent, this device serves as a core framer-to-ATM interworking engine in carrier-grade access equipment requiring precise timing alignment, echo cancellation integration, and deterministic cell transport across legacy TDM and ATM domains.

Technical Context

The PXB 4221E implements dual-path processing: one path handles generic framer interface (FALC/GIM/SYM/EC modes) for E1/T1 line termination, while the other executes ATM layer functions including cell scrambling/descrambling, HEC generation/correction, and OAM processing. Its internal clock recovery circuit (ICRC) supports SRTS, ACM, and FILTER PLL modes with fractional divider for jitter-tolerant synchronization to network-derived clocks.

It features dedicated hardware blocks for AAL5 segmentation (with RTS extraction, padding, and CAS conditioning) and reassembly (with sequence number protection, dummy cell insertion, and SDT-port synchronization), all managed via microprocessor interface and supported by external RAM for buffer storage. The UTOPIA Level 2 interface operates at 25 MHz with backpressure signaling for flow control.

Key Specifications

Pinout & Package

Package: 256-pin LQFP (28 mm × 28 mm, 0.4 mm pitch), RoHS-compliant, thermally enhanced for telecom line card operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar interworking element applications.

Compared with PM5352 and CX82310, the PXB 4221E uniquely integrates full 8-line E1/T1 framing, hardware AAL5 SAR, IMA, and clock recovery in one package - eliminating external framer, clock IC, and SAR accelerator components required by alternatives.

Availability

PXB 4221 E V3.4-G is available at Aetrix Electronics and suitable for DSLAM line cards, VoIP gateways, IMA concentrators, and echo canceller platforms requiring stable component supply and long-term lifecycle support in telecom infrastructure.

Supply support for PXB 4221 E V3.4-G 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

Infineon Technologies AG is a German semiconductor manufacturer specializing in power management, automotive, security, and communications ICs, with deep heritage in telecom silicon dating to Siemens' semiconductor division.

The PXB 4221E belongs to Infineon's IWE (Interworking Element) product line, engineered specifically for TDM-to-ATM interworking in carrier-access equipment where timing precision, protocol transparency, and hardware offload are critical.

FAQ

What clock sources does the PXB 4221E support for E1 line synchronization?

The PXB 4221E supports direct E1 line clock recovery via its internal Clock Recovery Circuit (ICRC), accepting 2.048 MHz or 8.192 MHz reference inputs. It implements SRTS, ACM, and FILTER PLL modes with fractional divider to lock onto network-derived timing with ±50 ppm tolerance and sub-10 ns jitter accumulation - meeting ITU-T G.823 requirements for primary rate interfaces.

Does the PXB 4221E support both structured and unstructured CES for voice transport?

Yes - the PXB 4221E supports both unstructured CES (bit-transparent transport) and structured CES with CAS (channel-associated signaling) preservation. In structured mode, it freezes CAS bits upstream during segmentation and reinserts them downstream during reassembly, maintaining compatibility with SS7, ISDN PRI, and legacy PBX signaling protocols without requiring external CAS processors.

Can the PXB 4221E operate in standalone mode without external microprocessor control?

No - the PXB 4221E requires initialization and runtime configuration via its 8-/16-bit microprocessor interface. All functional blocks (framer mode selection, ATM port setup, SAR channel mapping, PLL configuration) are register-controlled. While it executes segmentation/reassembly autonomously once configured, boot-up, fault handling, and dynamic reconfiguration depend on host processor interaction.

How does the PXB 4221E handle cell loss during reassembly?

Upon detecting missing cells (via sequence number gaps), the PXB 4221E inserts dummy cells into the reassembly buffer to maintain payload alignment and prevent downstream frame slips. This behavior is configurable per channel and complies with RFC 2680 for cell loss concealment in AAL5 CES applications, ensuring continuous voice stream delivery even under moderate packet loss conditions.