Infineon Technologies PEF 20451 E V1.3

Overview

PEF 20451 E V1.3 from Infineon Technologies is a programmable digital switching IC for wired communications systems, implementing a 256×256 time-slot interconnection matrix with H-Bus and PCM local bus interfaces. It supports subchannel (1-/2-/4-/8-bit), broadcast, multipoint, and stream-to-stream switching modes, operates at up to 8.192 MHz PCM clock rate, and integrates dual PLLs (APLL + digital PLL) for jitter-tolerant clock recovery and phase alignment in PBX, VoIP gateway, and router applications.

For engineers reviewing the PEF 20451 E V1.3 datasheet, PEF 20451 E V1.3 pinout, PEF 20451 E V1.3 application, or PEF 20451 E V1.3 equivalent, key selection criteria include H-Bus/PCM timing compliance, subchannel granularity support, interrupt-driven configuration register access, hardware reset timing (t_RST = 100 µs min), and dual-PLL synchronization capability in M- or H-mode.

Technical Context

The PEF 20451 E V1.3 implements a fully configurable time-division switching fabric with 256 input × 256 output time-slot crosspoint matrix, managed via indirect register addressing through an 8-/16-bit microprocessor interface. Its architecture includes separate H-Bus (up to 2.048 Mbps) and PCM (up to 8.192 Mbps) data paths, each with independent framing and bit-shifting logic.

It integrates two PLL subsystems: an Analog PLL (APLL) for low-jitter clock recovery from H-Bus reference (e.g., 2.048 MHz), and a digital PLL for PCM frame synchronization; both support fallback, phase alignment, and error-handling via dedicated status registers (ISTA1, IESTA1/2). Configuration is performed via CMD1/CMD2 command registers and SA/DA address registers.

Key Specifications

Pinout & Package

PEF 20451 E V1.3 is housed in a 144-pin LQFP package (20 mm × 20 mm, 0.5 mm pitch) with thermal pad. Power supply pins are distributed across VDD (3.3 V core), VDDIO (3.3 V I/O), and VSS planes; dedicated PLL analog supply (VDDA) and ground (VSSA) are isolated for noise immunity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar TDM switching applications.

Compared with PEF 20451 E V1.3, the PEF 20471 offers scalable capacity without software changes, while the PEF 24471 adds signal-processing features and ruggedization - making the PEF 20451 optimal for cost-sensitive, thermally benign PBX and CTI applications where 256×256 switching suffices.

Availability

PEF 20451 E V1.3 is available at Aetrix Electronics and suitable for PBX infrastructure, computer telephony adapters, and VoIP gateway designs requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for PEF 20451 E V1.3 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, and wired/wireless communications ICs, with global R&D and manufacturing facilities.

The PEF series belongs to Infineon's Wired Communications product line, designed specifically for TDM switching, protocol bridging, and clock management in legacy and hybrid telephony infrastructure - emphasizing configurability, jitter resilience, and multi-standard interoperability.

FAQ

What is the maximum supported PCM clock frequency for PEF 20451 E V1.3?

The PEF 20451 E V1.3 supports PCM clock frequencies up to 8.192 MHz, enabling full-rate E1 (32 time-slots × 256 kbps) and extended parallel PCM modes. This frequency is validated in the preliminary datasheet DS1 (Nov. 2001), Table 28, and corresponds to a 125 µs frame period with 8-bit parallel data width.

Does PEF 20451 E V1.3 support JTAG boundary scan for production testing?

Yes - the device implements full IEEE 1149.1-compliant JTAG (TCK/TMS/TDI/TDO) for boundary-scan testing, register access, and in-system programming. Pin definitions and TAP controller behavior are detailed in Section 4.7 of the preliminary datasheet, including support for EXTEST and SAMPLE/PRELOAD instructions.

How does the dual PLL architecture handle reference clock loss?

Upon loss of the primary reference (H-Bus or PCM), the device initiates clock fallback: the active PLL holds last valid frequency via internal loop filter charge retention, while the inactive PLL remains ready for switchover. Fallback timing and error detection are managed by the PLL Error Handling logic (Section 3.4.6), with status reported in IESTA1 register bits.

Can PEF 20451 E V1.3 perform simultaneous bidirectional switching between H-Bus and PCM ports?

Yes - the switching factory supports full-duplex, non-blocking time-slot mapping: one connection can route PCM time-slot N to H-Bus time-slot M, while another routes H-Bus time-slot X to PCM time-slot Y, all within the same frame. This is confirmed in Section 3.3.1.5 (Bidirectional Switching) and Figure 10 (Functional Block Diagram).