MPC745BPX350LE Guide: Specs, Pinout, and Replacements for Legacy PowerPC

In the late 90s and early 2000s, the PowerPC architecture was the king of embedded networking and industrial control. While the world has moved on to ARM and RISC-V, thousands of industrial machines, telecom switches, and avionics systems still rely on these robust processors.

The MPC745BPX350LE (originally from Motorola/Freescale, now NXP) is a classic example. It’s a 350 MHz workhorse that is now officially Obsolete (EOL).

If you are a maintenance engineer trying to repair a $50,000 industrial controller, finding accurate info on this chip is harder than finding the chip itself. This guide covers the technical specs, the tricky "LE" suffix, and why you cannot simply swap it for an MPC755.

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Table of Contents

1. Decoding the Part Number: What "BPX350LE" Means
2. Technical Specifications: The PowerPC 603e Legacy
3. Compatibility Trap: MPC745 vs. MPC755
4. Hardware Considerations: The BGA-255 Package
5. Sourcing & Replacement Strategy
6. Conclusion

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1. Decoding the Part Number: What "BPX350LE" Means

Freescale/NXP part numbers tell a specific story. Here is the breakdown for MPC745BPX350LE:

Segment	Code	Meaning
MPC745	Base Model	PowerPC 745 (G3 generation, no L2 cache pins).
B	Revision	Rev B (Silicon Revision). Indicates a mature manufacturing stepping.
PX	Package	Plastic BGA (PBGA). Specifically the 255-pin version.
350	Speed	350 MHz Clock Speed.
LE	Suffix	Standard (Leaded). See warning below.

⚠️ Critical Warning: The "LE" Suffix

In modern components, "LE" often hints at "Low Energy" or "Lead-Free." Not here. For the MPC745 series, the LE suffix typically designates the standard RoHS Non-Compliant (Leaded solder ball) version.

• Impact: If you are repairing a board for a strictly RoHS market (EU), ensure your exemption allows for leaded legacy parts, or look for a specifically marked "Lead-Free" variant (often rare for chips of this era).

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2. Technical Specifications: The PowerPC 603e Legacy

The MPC745 is essentially a streamlined version of the famous PowerPC 750 (G3). It was designed to be a lower-cost, lower-power solution for systems that didn't need massive external cache.

• Architecture: 32-bit PowerPC RISC (Superscalar).
• Clock Speed: 350 MHz.
• L1 Cache: 32KB Instruction + 32KB Data (On-die).
• L2 Cache: None. Unlike the MPC750/755, the MPC745 removed the external L2 cache interface to save pins.
• Voltage:
  • Core: 2.0V (Nominal).
  • I/O: 3.3V (Compatible with 2.5V).
• Power Dissipation: Very low (typically < 4W), making it ideal for fanless industrial enclosures.

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3. Compatibility Trap: MPC745 vs. MPC755

This is the most common mistake engineers make. You might see the MPC755 listed as a "drop-in replacement" in some broad comparisons. It is NOT.

Feature	MPC745 (This Chip)	MPC755
Package	255-Pin BGA (21x21mm)	360-Pin BGA (25x25mm)
L2 Cache	No Interface	Dedicated Interface
Compatibility	Drop-in for MPC740	Drop-in for MPC750

The Takeaway: You cannot solder an MPC755 onto an MPC745 footprint. The chips are physically different sizes.

• Correct Replacement Path: If you need a replacement, you must look for another MPC745 or potentially a PowerPC 603e / MPC740 (check pinout and voltage carefully, as the 745 was the "upgrade" to the 740).

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4. Hardware Considerations: The BGA-255 Package

The 255-pin FCPBGA (Flip-Chip Plastic Ball Grid Array) is a robust package, but dealing with "New Old Stock" (NOS) requires care.

1. Moisture Sensitivity (MSL): These chips have likely been sitting in a warehouse for 10-15 years.
2. Baking is Mandatory: Before reflowing this chip onto a board, you MUST bake it (typically 125°C for 24 hours).
   • Why? The plastic package absorbs moisture over time. Rapid heating during soldering turns that moisture into steam, cracking the chip from the inside (Popcorning).
3. Leaded Profile: Since this is likely a leaded (SnPb) component, use a standard leaded reflow profile (Peak ~220°C), not a high-temp lead-free profile.

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5. Sourcing & Replacement Strategy

Since NXP has discontinued this part, you won't find it at standard authorized distributors like DigiKey or Mouser.

Where to find it?

• Broker Market: You will need to rely on component brokers or legacy stock specialists.
• Aichiplink: We specialize in locating hard-to-find and obsolete silicon.

Verification Checklist:

• Date Codes: Look for codes from the mid-2000s (e.g., 04xx, 05xx).
• Ball Condition: Ensure the BGA balls are shiny and uniform. Dull or oxidized balls indicate poor storage.

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6. Conclusion

The MPC745BPX350LE is a piece of computing history that keeps critical infrastructure running. While it lacks the glitz of modern AI chips, its reliability in industrial environments is legendary. When replacing this CPU, remember to verify the package (BGA-255), respect the "Leaded" soldering requirements, and bake the chip before use.

Sourcing Obsolete NXP/Freescale Parts? Struggling to find legacy PowerPC processors? Visit Aichiplink.com to search for verified stock of MPC745BPX350LE and other discontinued components.

Search MPC745BPX350LE Stock Now

 

 

 

 

 

Written by Jack Elliott from AIChipLink.

 

AIChipLink, one of the fastest-growing global independent electronic   components distributors in the world, offers millions of products from thousands of manufacturers, and many of our in-stock parts is available to ship same day.

 

We mainly source and distribute integrated circuit (IC) products of brands such as Broadcom, Microchip, Texas Instruments, Infineon, NXP, Analog Devices, Qualcomm, Intel, etc., which are widely used in communication & network, telecom, industrial control, new energy and automotive electronics. 

 

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