MPC855TCZQ50D4557 - MPC8xx PowerQUICC MPU, 50 MHz, 357-BGA | NXP
MPN: MPC855TCZQ50D4557 ⚠ Last Time BuyMPC855TCZQ50D4557 Overview
An MPU (Microprocessor Unit) in the MPC8xx family integrates a PowerPC integer unit with dedicated on-chip peripherals that historically target telecommunications, networking, and embedded control applications. Unlike a generic microcontroller, the MPC8xx is built around the PowerPC architecture with a memory management unit and dual-bus Harvard architecture, while the on-chip CPM offloads serial communication from the core. This taxonomy places MPC8xx above single-core MCUs and below multi-core application processors in the embedded-computing hierarchy.
Key features include 4 KB instruction cache, 4 KB data cache, integrated floating-point unit, dual 10/100 Ethernet MACs via the CPM, and memory controller for SDRAM, SRAM, EPROM, and Flash. The device is qualified for commercial temperature range (0°C to +70°C) and supports JTAG boundary-scan test. Power management features include low-power doze and sleep modes with wake-up on external interrupt.
The 357-BGA package measures 25 mm × 25 mm with 1.27 mm pitch and is supplied in tray packaging. The -50 speed grade yields approximately 89 MIPS (Dhrystone 2.1) at 50 MHz. The integrated CPM and dual Ethernet MACs make this part especially efficient for legacy routing and telecom equipment where power dissipation and BOM count matter more than raw clock speed. The MPC8xx CPM runs independently of the core, allowing sustained serial throughput with minimal CPU load.
Typical applications include legacy enterprise routers, ISDN terminal adapters, WAN access multiplexers, industrial serial-control gateways, and legacy printer controllers. The dual Ethernet and multi-protocol serial support reduce external glue logic, while the BGA package supports high-density multilayer PCB designs used in networking line cards. The MPC8xx architecture remains in service across installed-base equipment that has been certified to specific firmware revisions, where re-validation cost makes platform migration uneconomical.
When designing with this device, verify thermal management for the BGA package - although the MPC855T at 50 MHz consumes roughly 1 W typical, a multi-layer PCB with thermal vias under the die-attached balls is recommended. The 357-BGA footprint has been used by multiple MPC8xx variants, enabling straightforward migration across speed grades within the same board layout.
Drop-in alternatives for MPC855TCZQ50D4557 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MPC855TCZQ50D4557 (same form factor and footprint) — differing in Core Architecture, Operating Temperature, Package.
MPC855TCZQ66D4
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MPC855TCZQ80D4
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MPC860TCZQ50D4
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →MPC852TCZQ50D4
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MPC855TCZQ50D4557 Maximum Ratings & Electrical Characteristics
| Core Architecture | PowerPC MPC8xx (MPC860-style) with CPM |
| Core Frequency | 50 MHz |
| Instruction Cache | 4 KB |
| Data Cache | 4 KB |
| Floating-Point Unit | Yes (integrated) |
| Communication Processor Module (CPM) | Yes (dual-port RAM with RISC serial controller) |
| Ethernet MAC | 2 × 10/100 Mbps (MII/RMII via CPM) |
| Serial Channels (SCC) | Up to 4 (HDLC/SDLC/UART/Transparent) |
| Serial Management Channels (SMC) | 2 |
| Package | 357-ball Plastic BGA (ZQ suffix), 25 × 25 mm, 1.27 mm pitch |
| Mounting Type | Surface Mount |
| Supply Voltage (I/O) | 3.3 V |
| Operating Temperature | 0 °C to +70 °C (commercial grade) |
| Speed Grade Suffix | ZQ = 50 MHz commercial |
| Order Code Suffix | D4557 (customer-specific tape/reel identifier) |
MPC855TCZQ50D4557 357-ball plastic bga (zq suffix), 25 × 25 mm, 1.27 mm pitch Pin Configuration Guide
Pin configuration for MPC855TCZQ50D4557 (357-ball plastic bga (zq suffix), 25 × 25 mm, 1.27 mm pitch package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for MPC855TCZQ50D4557.
Refer to the datasheet for full pin configuration.
Typical Applications
MPC855TCZQ50D4557 is suitable for 6 applications: Legacy Enterprise Router Line Card, ISDN Terminal Adapter / NT1+, WAN Access Multiplexer / DSLAM Line Card, Industrial Serial-Control Gateway, Legacy Printer/Imaging Controller Board, VoIP Access Gateway / Media Gateway.
Legacy Enterprise Router Line Card
The MPC855TCZQ50D4557 is well-suited to legacy enterprise router line cards that require dual 10/100 Ethernet MACs and multi-protocol serial support in a single PowerPC device. The integrated Communication Processor Module (CPM) handles HDLC framing and UART traffic without CPU intervention, leaving the 50 MHz PowerPC core available for routing-table lookups and control-plane tasks. The dual-MII Ethernet interfaces allow direct connection to two PHY devices, supporting separate LAN and WAN ports on the same card. Power dissipation of approximately 1 W typical at 50 MHz allows the part to operate without a heatsink on standard multilayer PCB designs. The 357-BGA package supports high-density trace routing required for high-speed address and data buses to external SDRAM.
Recommended
ISDN Terminal Adapter / NT1+
The MPC855TCZQ50D4557 fits ISDN NT1+ terminal adapters where multiple SCC channels are configured as HDLC controllers to terminate ISDN BRI links. The CPM's independent RISC serial controller sustains ISDN D-channel and B-channel throughput while the PowerPC core handles upper-layer signaling. The on-chip 4 KB instruction and 4 KB data caches are sufficient for the small footprint PPP/PPPoE stacks used in legacy CPE designs. The 357-BGA footprint allows the entire NT1+ design to fit on a single small-form-factor PCB. Commercial temperature grade (0 °C to +70 °C) meets indoor CPE environmental requirements.
Recommended
WAN Access Multiplexer / DSLAM Line Card
Legacy WAN access multiplexers and DSLAM line cards use the MPC855TCZQ50D4557 to aggregate multiple T1/E1 trunks or DSL links through the SCC channels. Each SCC can be configured as HDLC, UART, or transparent serial, allowing direct termination of T1/E1 framers without external glue logic. The 50 MHz PowerPC core handles PPP, frame-relay, and ATM AAL2 segmentation tasks. Two independent 10/100 Ethernet MACs connect the line card to the aggregation switch fabric. The 357-BGA package's thermal characteristics are well matched to the airflow available in central-office equipment racks.
Recommended
Industrial Serial-Control Gateway
Industrial serial-control gateways leverage the MPC855TCZQ50D4557 to bridge RS-232/RS-485 serial devices onto Ethernet. Each SCC channel can be mapped to an external transceiver, while the SMC channels handle slower auxiliary interfaces. The PowerPC core runs Modbus/TCP, DNP3, or IEC 60870-5-104 protocol stacks. The commercial temperature grade fits factory-floor cabinet environments. The 357-BGA footprint supports rugged PCB constructions with thermal vias and conformal coating.
Recommended
Legacy Printer/Imaging Controller Board
The MPC855TCZQ50D4557 served in legacy printer and imaging controller boards where dual Ethernet and multi-protocol serial interfaces were needed to connect print engines, scanners, and operator panels. The CPM offloads page-description-language interpretation and image-data streaming from the core. The on-chip MMU supports virtual-memory operating systems such as VxWorks and pSOS, which were standard for production-class printers of that era. The 357-BGA footprint accommodates the dense address/data bus routing to external SDRAM and Flash arrays required for print-image buffering.
Recommended
VoIP Access Gateway / Media Gateway
VoIP media gateways used the MPC855TCZQ50D4557 to terminate T1/E1 PCM trunks and bridge them onto Ethernet. The SCC channels in HDLC mode terminate the PCM span, while the integrated Ethernet MACs connect to the packet network. The PowerPC core runs the RTP/RTCP and signaling stacks. The dual Ethernet MACs allow separate signalling and bearer paths on different PHYs. The 50 MHz core is sufficient for low-channel-count media gateways (typically 4-8 simultaneous calls) where voice codecs are handled by a companion DSP.
Recommended
Recommended Products Summary
Engineering reference data for MPC855TCZQ50D4557 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MPC855TCZQ66D4 | MPC855TCZQ80D4 | MPC860TCZQ50D4 | MPC852TCZQ50D4 |
|---|---|---|---|---|---|
| Brand | NXP Semiconductors (formerly Freescale) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 357-BGA (ZQ) 25x25 mm | 357-BGA (ZQ) 25x25 mm - same | 357-BGA (ZQ) 25x25 mm - same | 357-BGA (ZQ) 25x25 mm - same | 357-BGA (ZQ) 25x25 mm - same |
| Core Frequency | 50 MHz | 66 MHz | 80 MHz | 50 MHz | 50 MHz |
| Core Architecture | MPC855T (PowerPC + CPM, dual Ethernet) | MPC855T (same die) | MPC855T (same die) | MPC860T (extended CPM) | MPC852T (reduced CPM) |
| Ethernet MACs | 2 × 10/100 | 2 × 10/100 | 2 × 10/100 | 2 × 10/100 | 2 × 10/100 |
| SCC Channels | Up to 4 | Up to 4 | Up to 4 | Up to 4 | Up to 2 |
| Instruction Cache | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB |
| Operating Temperature | 0 °C to +70 °C (commercial) | 0 °C to +70 °C | 0 °C to +70 °C | 0 °C to +70 °C | 0 °C to +70 °C |
| Lifecycle Status | Last-Time-Buy | Last-Time-Buy | Obsolete (limited stock) | Last-Time-Buy | Last-Time-Buy |
Key Differentiators
- CPM-offloaded serial communication (vs MPC852TCZQ50D4)
- 50 MHz commercial speed grade availability (vs MPC855TCZQ80D4)
- D4557 customer-specific order code (vs MPC855TCZQ50D4 (standard order code))
Design Notes
Estimated: at 50 MHz core, 3.3 V I/O, the MPC855T dissipates approximately 1.0 W typical. The 357-BGA package has a theta_JA of roughly 25-30 C/W on a standard 4-layer JEDEC test board, implying a 25-30 °C junction temperature rise. While a heatsink is not required at typical dissipation, recommended PCB practice is a thermal-via array under the die-attached BGA balls to spread heat into the internal ground pour. Verify with the manufacturer's thermal model for production builds.
The 357-BGA ZQ package uses 1.27 mm pitch, which is well within the capabilities of standard 0.2 mm via-pad processes. Route address and data buses in matched-length groups to satisfy SDRAM and external bus timing margins; the MPC855T external bus runs at the core clock divided by 2 at 50 MHz (25 MHz). Use controlled-impedance routing for Ethernet MII traces (typically 50 ohm single-ended) and keep MII lengths matched within 50 mil to satisfy IEEE 802.3 timing.
Do not confuse the D4557 order-code suffix with a die revision - the actual die is MPC855T, and the suffix is a customer-specific tape-and-reel identifier. The MPC8xx CPM requires careful initialization in software: SCC channel configuration, BRG (baud-rate generator) setup, and SI (serial interface) routing must all be programmed before serial traffic can flow. Power sequencing must bring Vdd core up before Vdd I/O to avoid latch-up; consult the MPC855T hardware-specification document for the recommended sequence.
The MPC855T external bus and Ethernet MII traces are the most signal-integrity-critical nets. Series-damping resistors (typically 22-33 ohm) on the address and data buses can reduce overshoot on long backplane-style traces. For Ethernet, source-termination close to the MAC balls is recommended for MII at 25 MHz. Keep CPM serial I/O traces away from the address/data bus to avoid coupling from periodic CPM activity into bus signals.
Compliance Information
The 357-BGA ZQ package is supplied in lead-free finishes per NXP standard product documentation, but explicit RoHS/REACH declarations for the specific D4557 order code should be confirmed via the NXP material declaration or distributor. The part is not qualified to AEC-Q100 - it targets commercial telecom/industrial segments.
