Texas Instruments PCI2250PGFG4

Overview

The PCI2250PGFG4 from Texas Instruments is a PCI-to-PCI bridge IC enabling hierarchical expansion of PCI bus systems. It supports two independent 32-bit, 33-MHz PCI buses, provides internal two-tier arbitration for up to four secondary bus masters, and implements programmable extension windows and port decode for custom I/O mapping - deployed in industrial backplane systems requiring electrical load isolation and hot-swap capability.

For engineers reviewing the PCI2250PGFG4 datasheet, PCI2250PGFG4 pinout, PCI2250PGFG4 application, or PCI2250PGFG4 equivalent, this page delivers verified technical context, real-world use cases, validated alternatives, and supply-chain support for legacy PCI infrastructure modernization and compact-PCI hot-swap designs.

Technical Context

The PCI2250PGFG4 implements full compliance with PCI Local Bus Specification Rev. 2.2 and PCI-to-PCI Bridge Architecture Specification Rev. 1.1. It supports both positive and subtractive decoding on the primary interface, with dual extension windows for memory-mapped I/O and serial/parallel port address decoding.

Its architecture includes independent read/write buffers per direction, five configurable secondary clock outputs (S_CLKOUT0–S_CLKOUT4), and integrated Compact-PCI Hot Swap support via HSLED/GOZ signaling. Power management conforms to PCI PMI Spec Rev. 1.0/1.1, including CLKRUN bridging for mobile docking scenarios.

Key Specifications

Pinout & Package

PCI2250PGFG4 is housed in a 176-pin Low-Profile Quad Flat Package (PGF-LQFP), 24 mm × 24 mm body, 0.5 mm lead pitch, thermally enhanced with exposed thermal pad (VCCP). Pinout follows TI's PGF terminal diagram (Figure 2–1, SCPS051).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PCI-to-PCI bridge applications.

Compared with PLX PCI9050-AB and Intel 21152AA, the PCI2250PGFG4 uniquely combines full PCI-to-PCI bridging, built-in CPCI hot-swap logic, and five secondary clock outputs - making it the only option for scalable, field-serviceable compact-PCI systems requiring electrical isolation and multi-peripheral clock distribution.

Availability

PCI2250PGFG4 is available at Aetrix Electronics and suitable for industrial backplane expansion, compact-PCI hot-swap systems, legacy PCI modernization, low-power docking stations, and ruggedized telecom chassis requiring stable component supply over extended product lifecycles.

Supply support for PCI2250PGFG4 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 focused on analog, embedded processing, and connectivity technologies, serving industrial, automotive, and communications markets.

The PCI2250PGFG4 belongs to TI's PCI Bus Solutions product line, engineered specifically for hierarchical PCI system expansion, electrical load mitigation, and Compact-PCI hot-swap compliance in mission-critical embedded platforms.

FAQ

What is the operating voltage range for the PCI2250PGFG4?

The PCI2250PGFG4 uses a 3.3-V core supply and features 5-V tolerant I/Os on both primary and secondary PCI interfaces. This allows seamless integration into mixed-voltage systems where legacy 5-V PCI slots coexist with modern 3.3-V logic, without level-shifting circuitry. The VCCP pin supplies the internal phase-locked loop and clock drivers, and must be decoupled per TI's layout guidelines in SCPS051 Section 7.

Does the PCI2250PGFG4 support PCI 2.3 or later specifications?

The PCI2250PGFG4 was designed and qualified to PCI Local Bus Specification Revision 2.2 and PCI-to-PCI Bridge Architecture Specification Revision 1.1, released in 1999. It does not support PCI 2.3 features such as 66-MHz operation, 64-bit addressing, or new power management states introduced post-2000. Its maximum clock rate remains 33 MHz, and all timing parameters align strictly with Rev. 2.2 requirements.

How many secondary clock outputs does the PCI2250PGFG4 provide, and are they configurable?

The PCI2250PGFG4 provides five dedicated secondary PCI clock outputs: S_CLKOUT0 through S_CLKOUT4. Each is individually enabled/disabled and can be configured for 33-MHz operation or tri-stated via the Secondary Clock Control Register (Section 5.19, SCPS051). These outputs drive secondary slots or peripherals, eliminating need for external clock buffers in multi-slot CPCI designs.

Can the PCI2250PGFG4 be used in a subtractive-only decoding configuration?

Yes - the PCI2250PGFG4 supports pure subtractive decoding on the primary interface, allowing it to act as a "default" bridge for undefined address ranges. This mode is selected via the Primary Decode Control Register (Section 5.9), and enables transparent pass-through of configuration cycles to downstream devices. Subtractive decoding is commonly used in legacy systems where precise memory window sizing is impractical.

Is the PCI2250PGFG4 pin-compatible with other members of the PCI2250 family?

The PCI2250PGFG4 is pin-compatible with the PCI2250PCM variant (160-pin QFP), sharing identical signal mapping and register layout. However, the PGF package has 176 pins versus PCM's 160, adding dedicated VCCP, additional GND, and expanded clock output routing. Migration between packages requires PCB redesign due to footprint and pin count differences - the PCI2250PGFG4 is not a drop-in replacement for PCM versions.