NXP Semiconductors MPC855TZQ50D4R2

Overview

MPC855TZQ50D4R2 from Freescale Semiconductor is a 32-bit Power Architecture™ communications processor with integrated CPM, 4 KB instruction/4 KB data cache, 10/100 Mbps Ethernet support via SCC, and UTOPIA-level ATM interface. It operates at 50 MHz, supports up to 32-bit data bus width, and targets embedded networking control in DSLAMs, enterprise routers, and industrial gateways.

For engineers reviewing the MPC855TZQ50D4R2 datasheet, MPC855TZQ50D4R2 pinout, MPC855TZQ50D4R2 application, or MPC855TZQ50D4R2 equivalent, key selection criteria include its 50 MHz CPU frequency, PBGA-357 package, IEEE 802.3u-compliant Ethernet capability, UTOPIA 1.0 ATM interface, and dual-voltage 3.3 V core / 5 V-tolerant I/O operation.

Technical Context

The MPC855TZQ50D4R2 implements a single-issue 32-bit Power Architecture core with MMU, 32 GPRs, and branch prediction. Its Communications Processor Module (CPM) includes four SCCs, two SMCs, one SPI, one I²C port, and a time-slot assigner supporting T1/E1 and ISDN framing.

It integrates a memory controller with eight banks, programmable wait states, DRAM/SRAM/Flash support, and PCMCIA socket controller for two sockets. The system integration unit provides PIT, RTC, watchdog, JTAG debug, and clock synthesizer - all operating under 3.3 V supply with 5 V-tolerant I/O pins except EXTAL/EXTCLK.

Key Specifications

Pinout & Package

MP855TZQ50D4R2 is housed in a 357-ball plastic ball grid array (PBGA) package with 25 mm × 25 mm footprint, 1.27 mm ball pitch, and ZQ package code per Freescale's mechanical specification (Case No. 1103D-02). Thermal resistance: RθJB = 13 °C/W, RθJC = 8 °C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar communications processor applications.

Compared with MPC855TZQ50D4R2, MPC860TZP50D4 offers reduced height but sacrifices PCMCIA capability, while MPC855TVR50D4 delivers identical performance in an equivalently specified package - making it the preferred alternative for footprint-consistent redesigns.

Availability

MPC855TZQ50D4R2 is available at Aetrix Electronics and suitable for DSLAM line cards, industrial protocol gateways, enterprise branch routers, and secure remote access appliances requiring stable component supply across extended product lifecycles.

Supply support for MPC855TZQ50D4R2 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 was a fabless semiconductor company specializing in embedded processors, analog, and connectivity solutions before its acquisition by NXP Semiconductors in 2015.

The MPC855T belongs to the PowerQUICC family of integrated communications controllers designed specifically for cost-sensitive, high-throughput embedded networking applications requiring both general-purpose processing and hardware-accelerated protocol handling.

FAQ

What is the maximum operating frequency of the MPC855TZQ50D4R2?

The MPC855TZQ50D4R2 is rated for a maximum CPU frequency of 50 MHz in 1:1 mode (CPU clock equals bus clock). It does not support higher frequencies like the 66 MHz or 80 MHz variants in the MPC860 family. Operation above 50 MHz is not permitted and may cause timing violations or functional failure. The part number suffix "50" explicitly denotes this 50 MHz rating, confirmed in Freescale's MPC860 Hardware Specifications Rev. 10.

Does the MPC855TZQ50D4R2 support IEEE 802.3u 100BASE-TX Ethernet?

Yes, the MPC855TZQ50D4R2 supports IEEE 802.3u 100BASE-TX Ethernet through its SCC peripherals, but only when configured with an external PHY device connected via MII or RMII interface. The chip itself contains the MAC layer and associated DMA engines; physical layer signaling requires external components. This capability is documented in Section 2 ("Features") and Table 1 of the MPC860 Hardware Specifications, where MPC855T is listed with "10/100" Ethernet support.

What package type and dimensions does the MPC855TZQ50D4R2 use?

The MPC855TZQ50D4R2 uses a 357-ball plastic BGA (PBGA) package with ZQ designation (Case No. 1103D-02), measuring 25 mm × 25 mm with 1.27 mm ball pitch and 1.2 mm body height. This matches Freescale's mechanical specification for "ZQ/VR" packages in Table 3 of the MPC860 Hardware Specifications Rev. 10. The ZQ code distinguishes it from the thinner ZP variant (0.9 mm height).

Can the MPC855TZQ50D4R2 operate with 5 V I/O signals?

The MPC855TZQ50D4R2 supports 5 V-tolerant I/O on most pins (except EXTAL and EXTCLK), with VIH up to 5.5 V and absolute maximum input voltage of VDDH + 0.3 V. However, VDDH must be 3.3 V nominal; applying 5 V to VDDH will damage the device. I/O buffers tolerate 5 V inputs safely only when VDDH is within 3.135–3.465 V, as specified in Table 6 of the hardware spec.

Is the MPC855TZQ50D4R2 pin-compatible with other MPC860 family members?

The MPC855TZQ50D4R2 shares the same 357-ball PBGA footprint and signal mapping as MPC860T, MPC860DP, and MPC860P in ZQ/VR packages, but differs in feature set: it lacks the second Ethernet controller and ATM UTOPIA interface present in higher-tier MPC860 variants. Pin compatibility is confirmed in Freescale's mechanical data (Table 3) and functional tables (Table 1), though register-level initialization and peripheral enablement differ per part number.