The MCM4464 series is a fast static RAM module for the R4000 processor, consisting of four MCM4464 modules that provide a total of 1MB of secondary cache. Each module contains nine MCM6709J fast static RAMs with a cache data size of 64K x 36. The tag portion, depending on the word line size, contains either two MCM6709J or one MCM6706J fast static RAMs. All input signals, except A0 and WE, are buffered using 74FBT2827 drivers with series 25 Ω resistors. The MCM6709J and MCM6706J are fabricated using high-performance silicon-gate BiCMOS technology. The static design eliminates the need for internal clocks or timing strobes. All 1MB R4000 supported secondary cache options are available. Single 5V ±10% power supply. All inputs and outputs are TTL compatible. Three-state outputs. Fast module access time: 12/15/17 ns. Zero wait-state operation. Unified or split secondary cache modules are available (see ordering information for details). Word line sizes of 4, 8, 16, and 32 are available (see ordering information for details). The pin compatible MCM44256 series is also available to support a full 4MB R4000 secondary cache. Decoupling capacitors are used for each fast static RAM and buffer, along with bulk capacitance for maximum noise immunity. High-quality multi-layer FR4 PWB with separate power and ground planes.
This handbook describes the Motorola MCM4464 fast SRAM series used as secondary cache for R4000 processors. It details the module architecture, pin assignments, and available configurations such as unified or split cache and various word‑line sizes.
The document includes absolute maximum ratings, DC and AC operating characteristics, read/write cycle timing tables, and ordering part numbers. It serves designers who need electrical parameters and timing data for integrating the MCM4464 modules into their systems.
| Supply Voltage (Operating Voltage Range) | 4.5 V – 5.5 V |
|---|---|
| Power Dissipation | 10 W |
| Operating Temperature | 0 °C – +70 °C |
| Input Low Voltage (VIL) | 0.8 V (typ) |
| Output High Voltage (VOH) | 2.4 V (typ) |
The recommended operating supply voltage is 4.5 V to 5.5 V.
The device can dissipate up to 10 W per I/O pin.
Word‑line sizes of 4, 8, 16, and 32 are available.
Four MCM4464 modules comprise a full 1 MB of secondary cache.