Texas Instruments PCI1251BGFNR

Overview

PCI1251BGFNR from Texas Instruments is a dual-slot PC Card controller IC bridging 32-bit PCI bus to 16-bit PC Card and 32-bit CardBus interfaces. It supports hot insertion/removal, 3.3-V core logic with universal 3.3-V/5-V PCI signaling compatibility, pipelined architecture enabling >130 MB/s throughput, and integrated zoomed video (ZV) path with 23 dedicated pins. It is used in notebook/desktop host systems requiring legacy PCMCIA expansion and CardBus peripheral support.

For engineers reviewing the PCI1251BGFNR datasheet, PCI1251BGFNR pinout, PCI1251BGFNR application, or PCI1251BGFNR equivalent, key selection considerations include dual-socket ExCA register compatibility, serialized IRQ multiplexing (8-way), TPS2206 serial power switch interface, PCI 2.2 and PC Card 1997 standard compliance, and ZV signal routing capability for VGA subsystem integration.

Technical Context

The PCI1251BGFNR implements a dual-function PCI device with separate configuration spaces for each socket (Function 0 = Socket A, Function 1 = Socket B), supporting both PCI master and slave roles. Its internal data path handles 8-/16-/32-bit card accesses via full 32-bit PCI cycles and enables fast posted writes to optimize bus utilization.

It integrates ExCA-compatible registers mappable in memory/I/O space, supports distributed DMA (DDMA) and PC/PCI DMA, and provides four general-purpose I/Os (GPIO0–GPIO3) with multifunction assignment (e.g., LEDA1/LEDA2, LOCK, INTA/INTB). Interrupt routing includes parallel PCI, parallel ISA, and serialized IRQSER modes with programmable style selection.

Key Specifications

Pinout & Package

PCI1251BGFNR is packaged in 256-pin MicroStar BGA (GFN package), 1.27-mm pitch, 17 mm × 17 mm body size. Pin assignments are defined for GFN and GJG variants per TI SCPS043A datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PC Card controller applications.

Compared with PCI1251BGFNR, PCI1250BGFNR offers reduced cost and footprint at the expense of dual-socket functionality and ZV support, while CL-PCIC98 lacks CardBus and ZV entirely-making PCI1251BGFNR the sole option for new designs requiring full 1997 PC Card Standard compliance and VGA-integrated video capture.

Availability

PCI1251BGFNR is available at Aetrix Electronics and suitable for notebook expansion, desktop docking stations, industrial embedded controllers, and VGA-zoomed video systems requiring stable component supply and long-term lifecycle support.

Supply support for PCI1251BGFNR 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 computing markets with high-reliability silicon solutions.

The PCI1251BGFNR belongs to TI's PC Card controller product line, designed specifically to enable seamless integration of legacy and next-generation PCMCIA peripherals into PCI-based host platforms with minimal board-level complexity.

FAQ

What is the primary function of the PCI1251BGFNR in a host system?

The PCI1251BGFNR serves as a dual-socket PCI-to-PC Card/CardBus bridge IC. It translates between the 32-bit PCI bus and two independent PC Card interfaces-supporting both 16-bit PC Card and 32-bit CardBus standards. The PCI1251BGFNR manages socket arbitration, power sequencing via TPS2206, hot insertion/removal, and interrupt routing, making it essential for adding modular I/O to notebooks and desktops.

Does the PCI1251BGFNR support CardBus operation at 33 MHz?

Yes, the PCI1251BGFNR fully supports CardBus operation at 33 MHz, as mandated by the 1997 PC Card Standard. Its internal pipeline architecture and optimized data path deliver sustained burst throughput exceeding 130 MB/s between CardBus and PCI domains-enabling high-bandwidth peripherals like Gigabit Ethernet or UDMA CompactFlash cards to operate at full specification speed.

How does the PCI1251BGFNR handle zoomed video (ZV) signal routing?

The PCI1251BGFNR provides an internally buffered ZV path that reassigns 23 pins (19 video + 4 audio) in 16-bit PC Card mode. When ZV is enabled, these signals route directly to the VGA controller without external components. This integrated approach guarantees CardBus loading compliance and eliminates layout uncertainty-critical for meeting timing and signal integrity requirements in mobile VGA subsystems.

Is the PCI1251BGFNR pin-compatible with the Intel 82365SL-DF controller?

The PCI1251BGFNR is ExCA register-compatible with the Intel 82365SL-DF, meaning software drivers and configuration logic can be reused. However, it is not pin-compatible: the PCI1251BGFNR uses a 256-pin BGA (GFN/GJG), while the 82365SL-DF uses a 128-pin PQFP. Board-level redesign is required-but firmware migration is simplified due to identical register maps and functional behavior.

What power supply voltages does the PCI1251BGFNR require?

The PCI1251BGFNR requires five distinct supply rails: VCC (3.3 V core logic), VCCA/VCCB (3.3 V clamping for PC Card A/B interfaces), VCCI (3.3 V for interrupt subsystem and GPIOs), VCCP (3.3 V or 5 V for PCI signaling), and VCCZ (3.3 V or 5 V for ZV interface). Each rail has defined sequencing requirements per the datasheet's Power Supply Sequencing section to ensure reliable initialization and hot-swap operation.