Renesas IDT79R4700-100G

Overview

IDT79R4700-100G from Integrated Device Technology is a 64-bit RISC microprocessor implementing the MIPS-III ISA, operating at 100 MHz with 5V supply, featuring 16KB instruction and 16KB data caches, a two-way set-associative cache architecture, and full software and pin compatibility with the R4XXX processor family - deployed in LAN switches, routers, and color printers.

For engineers reviewing the IDT79R4700-100G datasheet, IDT79R4700-100G pinout, IDT79R4700-100G application, or IDT79R4700-100G equivalent, key selection criteria include 64-bit virtual address space (256 GB user mode), 64GB physical address support, JTAG debug interface, 179-pin PGA package, and standby-mode power management via WAIT instruction.

Technical Context

The IDT79R4700-100G implements a simple 5-stage pipeline with integer and floating-point execution units decoupled for parallel operation. It integrates a system control co-processor (CP0) managing MMU functions via a 96-entry fully associative Joint TLB, plus separate 2-entry ITLB and 4-entry DTLB for low-latency virtual-to-physical translation.

Its memory subsystem supports non-overlapping 64-bit SysAD bus transfers at up to 500 MB/s peak bandwidth, with programmable boot-time modes controlling clock divisors, endian mode, write protocols (pipelined writes or write re-issue), and output driver strength - all configured via 256-bit serial boot stream.

Key Specifications

Pinout & Package

Package: 179-pin Pin Grid Array (PGA), cavity-down construction optimized for thermal dissipation in 0°C to +85°C case temperature operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 64-bit RISC microprocessor applications.

Compared with IDT79R4700-100G, the -133G and -200G variants offer scalable performance within the same software ecosystem and mechanical footprint - enabling platform reuse across cost- and performance-tiered products without redesigning board layout or firmware abstraction layers.

Availability

IDT79R4700-100G is available at Aetrix Electronics and suitable for LAN switches, enterprise routers, and color laser printer engines requiring stable component supply across extended product lifecycles.

Supply support for IDT79R4700-100G 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

Integrated Device Technology (IDT) is a fabless semiconductor company specializing in timing, memory interface, RF, and embedded processor solutions for communications and computing infrastructure.

IDT79R4700-100G belongs to IDT's RC4700 processor family - designed for high-performance, low-power embedded networking and imaging applications requiring 64-bit processing, integrated MMU, and deterministic real-time response.

FAQ

What is the operating voltage requirement for IDT79R4700-100G?

IDT79R4700-100G requires a nominal 5 V power supply, consistent with the "R" series designation in IDT's naming convention. This distinguishes it from the 3.3 V "RV" variants and mandates use of 5 V regulators and level-shifting circuitry when interfacing with 3.3 V peripherals. The device incorporates dynamic power management but does not support dual-voltage I/O operation.

Does IDT79R4700-100G support big-endian or little-endian operation?

IDT79R4700-100G supports both endianness modes, selected at boot time via bit 8 of the 256-bit serial mode stream. When bit 8 = 1, the processor operates in big-endian mode - essential for compatibility with legacy telecom and printing firmware. When bit 8 = 0, it defaults to little-endian. This configuration is latched at power-on reset and cannot be changed dynamically during runtime.

How does the TLB architecture of IDT79R4700-100G improve real-time determinism?

IDT79R4700-100G uses a 96-entry fully associative Joint TLB (JTLB) with programmable locking capability. Critical kernel mappings can be locked to prevent random replacement, ensuring zero-latency virtual-to-physical translation for time-sensitive ISR handlers or real-time buffers. Combined with per-page cache coherency attributes, this enables predictable worst-case execution time in industrial gateways and protocol stacks.

Can IDT79R4700-100G execute floating-point operations independently of the integer unit?

Yes, IDT79R4700-100G integrates a fully autonomous floating-point co-processor compliant with IEEE 754. It decodes and executes FP instructions in parallel with the integer pipeline, supporting overlapped multiply-add operations. Latencies (e.g., 4-cycle ADD, 61-cycle DIV for double precision) are documented in the hardware manual, and precise exceptions are maintained for debugging mission-critical applications.

What boot-time configuration options are available for IDT79R4700-100G?

IDT79R4700-100G accepts a 256-bit serial boot stream that configures clock divisors (bits 7:5), output driver strength (bits 14:13), write protocol mode (bits 10:9), and endian selection (bit 8). These settings define fundamental timing, signal integrity, and system interface behavior - allowing one hardware design to support multiple speed grades and application profiles via EEPROM programming.