MC68882RC33A - 33MHz 68040 FPU Co-Processor 68-PGA | NXP
MPN: MC68882RC33A ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $89.5 | $89.50 |
| 10 | $78.2 | $782.00 |
| 100 | $69.95 | $6,995.00 |
| 500 | $62.4 | $31,200.00 |
| 1,000 | $55.8 | $55,800.00 |
MC68882RC33A Overview
A floating-point co-processor is a specialized arithmetic processor that operates in parallel with the main CPU. The MC68882 belongs to the hierarchy: FPU co-processor -> numeric co-processor -> specialized IC -> microprocessor peripheral. It offloads transcendental functions (sine, cosine, tangent, exponential, logarithm) and IEEE-conformant arithmetic from the host, freeing integer cycles for control and I/O.
Key features include full IEEE 754-1985 compliance with rounding modes and gradual underflow, eight 80-bit floating-point data registers accessible as a register stack, and a 33 MHz operating frequency for the host-side M-Bus interface. The device supports four rounding modes (round to nearest, toward zero, toward plus infinity, toward minus infinity) and seven floating-point data formats. On-chip exception handling and an extended-precision pipeline minimize software intervention.
From an architectural perspective, the MC68882 implements a multi-stage execution pipeline and a fully-conforming IEEE exception model. The 80-bit internal data path and 67-bit mantissa deliver extended precision beyond the 53-bit mantissa required by IEEE double precision, supporting scientific and engineering workloads that demand extra headroom.
Typical applications include legacy M68K workstation upgrades, industrial motion-control systems with floating-point servo loops, scientific instrumentation, aerospace simulation hardware, and repair/maintenance of vintage Sun/HP/Apollo workstation motherboards. It is also used in educational platforms where 68020/68030 systems are still maintained.
When designing, ensure the host CPU is a 68020 or 68030 (the 68040 has an integrated FPU and does not accept an external MC68882). Decoupling and PGA socket quality are critical for reliable operation at 33 MHz.
This page consolidates distributor pricing, drop-in variants of the same die/package, lifecycle status, and design notes not always present in the original datasheet, giving engineers a single source for sourcing and substitution decisions.
Drop-in alternatives for MC68882RC33A — 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 MC68882RC33A (same form factor and footprint) — differing in Mounting Type, Operating Frequency, RoHS Status, Floating-Point Registers, Supply Voltage.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68882RC40A
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$89 / Unit
View Datasheet →MC68882RC50A
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$84.2 / Unit
View Datasheet →MC68882RC25A
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$59.5 / Unit
View Datasheet →MC68882EI33A
✅ Drop-In📋 Reference alternative (not in catalog)
MC68882RC33B
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MC68882RC33A Maximum Ratings & Electrical Characteristics
| Device Type | Floating-Point Unit (FPU) Co-Processor |
| Compatible Host CPU | MC68020, MC68030 |
| Operating Frequency | 33 MHz |
| Package | 68-PGA (Pin Grid Array), 26.92 x 26.92 mm |
| Mounting Type | Through-Hole (PGA) |
| Data Formats | IEEE 754: Single, Double, Extended Precision |
| Internal Data Path | 80-bit (67-bit mantissa) |
| Floating-Point Registers | 8 x 80-bit (register stack) |
| Rounding Modes | 4 (nearest, zero, +inf, -inf) |
| Supply Voltage | 5.0 V (typical) |
| Operating Temperature | 0C to +70C |
| Bus Interface | M-Bus (Motorola co-processor bus) |
| On-Chip Exception Handling | Yes (IEEE 754 exceptions) |
| Transcendental Support | Hardware sin, cos, tan, exp, log |
MC68882RC33A 68-pga (pin grid array), 26.92 x 26.92 mm Pin Configuration Guide
Pin configuration for MC68882RC33A (68-pga (pin grid array), 26.92 x 26.92 mm 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 MC68882RC33A.
Refer to the datasheet for full pin configuration.
Typical Applications
MC68882RC33A is suitable for 6 applications: M68K Workstation FPU Upgrade, Industrial Motion Control Platform, Scientific Instrumentation Front-End, Aerospace Simulation Hardware, Vintage Sun/HP/Apollo Motherboard Repair, M68K Educational Platform.
M68K Workstation FPU Upgrade
The MC68882RC33A attaches to a 68020 or 68030 host CPU to deliver IEEE 754 hardware floating-point performance on legacy M68K workstations. Its 33 MHz operating speed matches the host bus cycle, and the on-chip 8-register 80-bit FPU stack accelerates single/double/extended-precision arithmetic by 10-50x over software emulation. Engineers typically place the FPU in the dedicated co-processor socket adjacent to the CPU, sharing the M-Bus interface. The 68-pin PGA's 26.92 x 26.92 mm footprint requires a high-quality socket to maintain signal integrity at 33 MHz. Compared with a software-emulated FPU, hardware acceleration enables real-time CAD, 3D graphics transforms, and DSP workloads on platforms like the Sun-3 and HP 9000/300 series.
Recommended
Industrial Motion Control Platform
The MC68882RC33A enables floating-point servo loops on industrial motion-control platforms that still run on 68030-class CPUs. Its IEEE 754 conformance with full rounding and exception handling delivers the deterministic numeric behavior required for PID control and forward/inverse kinematic transforms in robotics. The on-chip transcendental hardware (sin, cos, tan, exp, log) accelerates trajectory-planning math without taxing the host. At 33 MHz, control loops running at 1 kHz update rate have ample margin for I/O and communication. The wide operating temperature range of the commercial-grade part (0C to +70C) suits most factory-floor enclosures, and the PGA package provides the mechanical robustness needed for industrial vibration environments.
Recommended
Scientific Instrumentation Front-End
Scientific instruments such as spectrum analyzers, electron microscopes, and chromatography data systems historically used 68030+MC68882 platforms for real-time signal processing. The MC68882's 80-bit extended-precision internal path (67-bit mantissa) exceeds IEEE 754 double precision, providing extra numerical headroom for FFT accumulation and curve-fitting algorithms. Hardware transcendental functions speed up waveform synthesis and statistics. Engineers design the FPU into the co-processor socket alongside the host CPU and use the 33 MHz M-Bus bandwidth for tight CPU-FPU coupling. The part's IEEE 754 compliance simplifies regulatory traceability for measurement applications.
Recommended
Aerospace Simulation Hardware
The MC68882 family served aerospace simulation and training platforms where M68K CPUs provided long-term lifecycle stability. The 33 MHz version delivers IEEE 754 floating-point performance for flight-dynamics models, radar-return simulation, and six-degree-of-freedom motion algorithms. Aerospace programs valued the part's deterministic exception handling and the ability to run unmodified Fortran scientific code. The PGA package's through-hole mounting is well-suited to conduction-cooled chassis used in airborne simulators. For new aerospace programs, the part is typically sourced through Rochester Electronics' authorized continuing-stock program.
Recommended
Vintage Sun/HP/Apollo Motherboard Repair
Sun-3, HP 9000/300, Apollo DN3500, and Next-station systems all used 68030+MC68882 as the standard processor pair, and the MC68882RC33A is the canonical replacement for failed FPU chips on these motherboards. The 68-pin PGA socket accepts the part directly; repair engineers should clean the socket and verify pin alignment before insertion. System diagnostics that report FPU presence/type will identify the MC68882RC33A correctly because the IEEE 754 instruction set is unchanged across speed grades. Sourcing through Rochester Electronics or verified independent distributors is critical to avoid counterfeit parts.
Recommended
M68K Educational Platform
University courses on computer architecture and assembly programming still use 68020+MC68882 platforms because the M68K instruction set is widely taught and the FPU's IEEE 754 model is exemplary for learning floating-point representation. The MC68882RC33A at 33 MHz provides a hands-on platform for studying pipelined FPU design, rounding modes, exception handling, and stack-register architectures. Educational labs typically obtain parts from Rochester Electronics' legacy inventory because new production has ceased. The 68-pin PGA package is large enough for students to probe signals with oscilloscopes during lab exercises.
Recommended
Recommended Products Summary
Engineering reference data for MC68882RC33A — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68882RC40A | MC68882RC50A | MC68882RC25A | MC68882EI33A | MC68882RC33B |
|---|---|---|---|---|---|---|
| Package | 68-PGA (26.92x26.92 mm) | 68-PGA (same) | 68-PGA (same) | 68-PGA (same) | 68-PGA (same) | 68-PGA (same) |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Operating Frequency | 33 MHz | 40 MHz | 50 MHz | 25 MHz | 33 MHz | 33 MHz |
| Temperature Grade | Commercial (0C to +70C) | Commercial | Commercial | Commercial | Industrial (extended) | Commercial |
| IEEE 754 Conformance | Full (1985) | Full (1985) | Full (1985) | Full (1985) | Full (1985) | Full (1985) |
| FP Registers | 8 x 80-bit | 8 x 80-bit | 8 x 80-bit | 8 x 80-bit | 8 x 80-bit | 8 x 80-bit |
| Compatible Host CPU | MC68020, MC68030 | MC68020, MC68030 | MC68020, MC68030 | MC68020, MC68030 | MC68020, MC68030 | MC68020, MC68030 |
| Lifecycle Status | Last-time-buy | Last-time-buy | Obsolete | Obsolete | Last-time-buy | Last-time-buy |
Key Differentiators
- Standard commercial-grade speed grade (vs MC68882EI33A)
- 33 MHz matches the most common 68030 host clock (vs MC68882RC40A (40 MHz))
- IEEE 754 hardware conformance eliminates software emulation (vs Software FPU emulation on a 68030)
Design Notes
Do not pair the MC68882RC33A with a 68040 host: the 68040 contains an integrated FPU and disables the external co-processor interface. Verify your host CPU is a 68020 or 68030 before designing in the FPU. The 33 MHz speed grade must match the host bus clock; using a 25 MHz FPU with a 33 MHz host causes M-Bus timing violations, while a 40/50 MHz FPU at 33 MHz host may also fail if the host expects a 33 MHz FPU at reset.
Use a high-quality PGA socket with machined or dual-beam contacts rated for 33 MHz+ signaling. Surface contamination and bent pins are the most common causes of FPU detection failures. Place decoupling capacitors (0.1 uF ceramic + 10 uF tantalum) on every VCC pin within 5 mm of the package. Maintain a solid ground plane beneath the PGA cavity to control return-path impedance on the M-Bus signals.
Estimated: At 33 MHz M-Bus toggle rates, the 68-pin PGA's lead inductance (~10 nH per pin) produces non-trivial switching noise on VCC/GND. A four-layer PCB with dedicated power and ground planes is strongly recommended over a two-layer design. Keep M-Bus traces short and matched, and provide series damping resistors (22-33 ohm) on the longest M-Bus lines if reflections appear on the scope.
Estimated: Power dissipation of the MC68882RC33A at 33 MHz is approximately 1.0-1.5 W from a 5 V supply. The 68-PGA's exposed die cavity provides good thermal coupling to a socket-mounted heatsink if required. In enclosed chassis without airflow, consider a small clip-on heatsink; in most workstation and industrial applications, natural convection is sufficient.
Compliance Information
Compliance values not present in verified distributor data; the MC68882 is a legacy product from the original Motorola/NXP line, and detailed compliance records for the original PGA parts are not consistently published. Rochester Electronics typically provides compliance documentation on request for authorized continuing-stock parts.
