Renesas IDT79RV4700-175GH

Overview

IDT79RV4700-175GH from Integrated Device Technology is a 3.3V, 175 MHz, 64-bit RISC microprocessor implementing the MIPS-III ISA with 16KB instruction and 16KB data caches, a two-way set-associative TLB, and integrated floating-point unit - deployed in high-throughput embedded networking systems such as LAN switches and routers.

For engineers reviewing the IDT79RV4700-175GH datasheet, IDT79RV4700-175GH pinout, IDT79RV4700-175GH application, or IDT79RV4700-175GH equivalent, key selection criteria include its 64-bit virtual address space (256 GB user mode), 200 MHz max clock capability (mode-bit configurable), 3.3V supply requirement, JTAG debug interface, and PGA-179 package compatibility with legacy R4XXX designs.

Technical Context

The IDT79RV4700-175GH uses a simple 5-stage pipeline with fully bypassed integer register file (32 × 64-bit GPRs + HI/LO), autonomous integer multiply/divide unit, and IEEE 754-compliant floating-point co-processor supporting single/double-precision arithmetic with precise exception handling. It executes MIPS-III instructions with full upward software compatibility to R3000/R4000 families.

Its memory subsystem includes a flexible MMU with 96-entry fully associative Joint TLB, two-entry ITLB, and four-entry DTLB - all supporting per-page cache coherency attributes (uncached, write-back, write-through) and configurable page sizes from 4KB to 16MB. The system interface operates at up to 67 MHz with non-overlapping read/write protocols and pipelined write support.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT79R4700-175GH, the 5V IDT79R4700-175GH offers identical compute capability but requires higher supply voltage and delivers lower thermal efficiency, while the RC64474-175GH provides identical functionality under alternate branding with equivalent lifecycle support.

Availability

IDT79RV4700-175GH is available at Aetrix Electronics and suitable for LAN switches, routers, and color printer controllers requiring stable component supply across extended industrial lifecycles.

Supply support for IDT79RV4700-175GH 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) was a U.S.-based semiconductor company specializing in high-performance timing, memory interface, and embedded processor solutions before its acquisition by Renesas Electronics in 2019.

The IDT79RV4700-175GH belongs to IDT's RC4700 family - designed specifically for cost-sensitive, thermally constrained embedded networking and imaging applications requiring MIPS-III compatibility and integrated memory management.

FAQ

What is the operating voltage range for the IDT79RV4700-175GH?

The IDT79RV4700-175GH operates exclusively at 3.3 V ± 0.3 V, distinguishing it from the 5V IDT79R4700-175GH variant. This reduced voltage enables lower dynamic power consumption and improved thermal performance in dense PCB layouts. The "RV" prefix explicitly denotes the 3.3V version, and operation outside this range may cause functional failure or accelerated wear. All I/O pins are 3.3V-tolerant and do not require level-shifting when interfacing with other 3.3V logic.

Does the IDT79RV4700-175GH support big-endian or little-endian operation?

The IDT79RV4700-175GH supports both endianness modes, selected at boot time via bit 8 of the 256-bit serial mode stream: '0' configures little-endian, '1' configures big-endian. This setting is latched during power-on initialization and remains fixed until reset. The choice impacts memory-mapped peripheral register interpretation and data structure layout in software - firmware must be compiled accordingly. No runtime switching is supported.

How does the TLB architecture of the IDT79RV4700-175GH improve real-time determinism?

The IDT79RV4700-175GH implements a 96-entry fully associative Joint TLB with lockable entries, enabling critical code and data pages to remain resident without eviction. Combined with random replacement and wired-entry support, this allows hard real-time tasks to guarantee worst-case memory access latency. Unlike software-managed TLBs, the hardware JTLB eliminates TLB miss interrupts for locked regions - a key enabler for deterministic interrupt response in router forwarding and industrial gateway applications.

Can the IDT79RV4700-175GH execute instructions from external memory without caching?

Yes - the IDT79RV4700-175GH supports uncached execution via kseg1 (uncached kernel physical address space), which maps addresses 0xA0000000–0xBFFFFFFF directly to the SysAD bus without instruction or data cache involvement. This mode is used for boot ROM, memory-mapped peripherals, or debugging where cache coherency cannot be guaranteed. Uncached access incurs full bus latency but ensures strict ordering and visibility of all memory-mapped I/O operations.

What debug capabilities does the IDT79RV4700-175GH provide?

The IDT79RV4700-175GH includes IEEE 1149.1 JTAG Test Access Port (TAP) controller with TDI/TDO/TCK/TMS pins, supporting boundary-scan disabled but enabling processor initialization, halt/resume control, and register inspection via standard JTAG debug tools. It does not implement full IEEE 1149.1 boundary-scan, but the TAP is fully functional for CPU-level debugging. No SWD or proprietary debug interfaces are present - JTAG is the sole standardized debug path for the IDT79RV4700-175GH.