NXP Semiconductors MPC755BRX350LE

Overview

MPC755BRX350LE from Freescale Semiconductor is a 350 MHz PowerPC™ RISC microprocessor with integrated L2 cache controller, 32 KB instruction and 32 KB data L1 caches, 2.0 V core supply, and 60x bus interface - deployed in embedded networking and industrial control systems requiring deterministic real-time execution and thermal-aware power management.

For engineers reviewing the MPC755BRX350LE datasheet, MPC755BRX350LE pinout, MPC755BRX350LE application, or MPC755BRX350LE equivalent, this page delivers verified package mapping (360-ball PBGA), confirmed L2 cache interface support, validated 350 MHz core frequency at 2.0 V ±100 mV, and exact thermal sensor resolution (±4°C) per Freescale MPC755EC Rev. 8.

Technical Context

The MPC755BRX350LE implements the PowerPC architecture with dual fixed-point units (FXU1/FXU2), a pipelined floating-point unit supporting IEEE 754 single/double precision, and a 64-entry branch target instruction cache (BTIC) enabling four-instruction fetch per cycle. It features hardware-managed out-of-order execution with six-entry reorder buffer and completion unit.

Its memory subsystem includes 128-entry two-way set-associative TLBs, eight BATs per domain, and an L2 cache interface supporting 256 KB–1 MB external synchronous BurstRAMs with configurable core-to-L2 divisors (÷1 to ÷3). Thermal management is enabled via on-die sensor with 4°C resolution and software-accessible SPRs (THRM3).

Key Specifications

Pinout & Package

Package: 360-ball plastic ball grid array (PBGA), 27 mm × 27 mm, 1.27 mm pitch, JEDEC MO-205AC compliant. Pinout conforms to Freescale MPC755EC Rev. 8 Section 5 ("Pin Assignments") and Section 6 ("Pinout Listings").

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RISC microprocessor applications.

Compared with MPC755BRX350LE, MPC745BRX350LE removes L2 interface logic to reduce die size and cost but retains identical real-time execution capability; MPC750FXZU350B trades thermal intelligence and debug for smaller package and lower core voltage - neither offers pin-compatible replacement due to differing ball counts and missing thermal/signal pins.

Availability

MPC755BRX350LE is available at Aetrix Electronics and suitable for industrial PLC controllers, telecom line cards, medical imaging subsystems, and avionics data concentrators requiring stable component supply across extended product lifecycles.

Supply support for MPC755BRX350LE 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

Freescale Semiconductor (now part of NXP Semiconductors) was a leading designer of embedded processors, analog, and connectivity solutions for automotive, industrial, and networking markets.

The MPC755BRX350LE belongs to the PowerPC 7xx family - engineered for high-performance, thermally constrained embedded systems demanding deterministic real-time behavior, hardware-assisted power management, and seamless migration from MPC740/750 platforms.

FAQ

What is the maximum guaranteed operating frequency of the MPC755BRX350LE?

The MPC755BRX350LE is binned and tested to operate reliably at 350 MHz under Freescale's recommended conditions: core voltage 1.90–2.10 V, junction temperature ≤105°C, and SYSCLK 25–100 MHz. This rating is documented in Table 8 of MPC755EC Rev. 8 and applies specifically to the BRX350LE speed grade - not to lower-binned variants like BRX300LE.

Does the MPC755BRX350LE support L2 cache, and how is it implemented?

Yes, the MPC755BRX350LE includes a dedicated L2 cache interface with internal tags and 64-bit data bus - unlike the MPC745 which omits this block. It supports external synchronous BurstRAMs (256 KB–1 MB), configurable core-to-L2 divisors (÷1 to ÷3), and sectored line sizes (64 or 128 bytes). This interface is explicitly confirmed in Section 2 ("Features") and Figure 1 of the MPC755EC Rev. 8 specification.

What package type is used for the MPC755BRX350LE, and why does it matter?

The MPC755BRX350LE uses a 360-ball plastic BGA (PBGA) package per Table 4 and Section 7 of MPC755EC Rev. 8. Freescale recommends PBGA over ceramic BGA (CBGA) for superior long-term board interconnect reliability. The 360-ball count and 27 mm × 27 mm footprint are critical for PCB layout - mismatched packages (e.g., 255-ball MPC745 PBGA) prevent mechanical or electrical compatibility.

How does the thermal management assist unit (TAU) function in the MPC755BRX350LE?

The MPC755BRX350LE integrates an on-die thermal sensor with 4°C resolution and ±12°C accuracy, feeding dedicated SPRs (THRM3) for software-controlled temperature regulation. When junction temperature exceeds a programmable threshold, THRM_INT asserts to trigger OS-level throttling. This capability is detailed in Table 5 and Section 4.1 of MPC755EC Rev. 8 - and is absent in MPC745 and earlier MPC750 derivatives.

Can the MPC755BRX350LE operate with both 2.5 V and 3.3 V I/O interfaces?

Yes, the MPC755BRX350LE supports selectable 2.5 V or 3.3 V I/O thresholds via BVSEL and L2VSEL pins, sampled at HRESET deassertion. Table 2 confirms this for revision E parts (including MPC755BRX350LE), and Table 3 lists corresponding OVDD/L2OVDD ranges (2.375–2.625 V or 3.135–3.465 V). These pins must remain static during operation - dynamic switching is unsupported and violates specification.

What distinguishes the MPC755BRX350LE from the MPC745BRX350LE beyond L2 support?

Beyond the absence of L2 interface logic, the MPC745BRX350LE lacks the L2 address/data buses (17-bit L2A[16:0], 64-bit L2D[63:0]), L2 control signals (L2CLK, L2OE, L2WE), and associated power pins (L2AVDD, L2OVDD). Its thermal characteristics differ slightly (RθJA = 31°C/W vs. 31°C/W for PBGA), but its core, L1 cache, 60x bus, and power management modes are functionally identical - making it a viable alternative only when L2 expansion is excluded.