Renesas IS82C59A-12Z96

Overview

IS82C59A-12Z96 from Intersil is a CMOS Priority Interrupt Controller designed to manage up to eight vectored, prioritized interrupt requests in 8080/85 and 80C86/88/286-based systems. It operates at 12.5MHz, supports edge- or level-triggered inputs, features fully static TTL-compatible logic, and delivers low-power operation with ICCOP ≤ 1mA/MHz and ICCSB ≤ 10μA.

For engineers reviewing the IS82C59A-12Z96 datasheet, IS82C59A-12Z96 pinout, IS82C59A-12Z96 application, or IS82C59A-12Z96 equivalent, this device serves as a drop-in replacement for legacy NMOS 8259A in industrial control, embedded instrumentation, and retro-computing platforms requiring programmable priority resolution, cascading to 64 levels, and dual-mode (8080/85 vs. 80C86) vectoring support.

Technical Context

The IS82C59A-12Z96 implements a fully static CMOS architecture with dedicated priority resolver, interrupt mask register (IMR), in-service register (ISR), and interrupt request register (IRR). Its read/write logic accepts Initialization Command Words (ICW1–ICW4) and Operation Command Words (OCW1–OCW3) to configure cascading, masking, AEOI, and microprocessor mode (8080/85 or 80C86/88/286).

It uses three cascade lines (CAS0–CAS2) for master/slave coordination, supports buffered and non-buffered modes via SP/EN, and provides interrupt vectoring through D7–D0 with distinct timing sequences: three INTA pulses for 8080/85 (including CALL opcode 0xCD), two INTA pulses for 80C86/88/286 (vector byte only). Internal pull-ups on IR0–IR7 ensure robust level-triggered operation.

Key Specifications

Pinout & Package

IS82C59A-12Z96 is housed in a 28-lead PLCC (Plastic Leaded Chip Carrier) package with Pb-free matte tin termination, RoHS compliant, and rated for −40°C to +85°C operation. The package uses JEDEC standard outline N28.45 and supports tape-and-reel delivery (96-unit reel).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar priority interrupt controller applications.

Compared with IS82C59A-12Z96, IS82C59AZ-12Z96 offers identical performance with enhanced RoHS compliance documentation, while CS82C59A-12Z96 sacrifices industrial temperature range for lower unit cost-making the IS82C59A-12Z96 the optimal balance of ruggedness, compatibility, and supply-chain continuity.

Availability

IS82C59A-12Z96 is available at Aetrix Electronics and suitable for industrial PLC backplanes, retro-computing expansion cards, and embedded test equipment requiring stable component supply, long-lifecycle support, and guaranteed Pb-free compliance.

Supply support for IS82C59A-12Z96 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

Intersil (now part of Renesas Electronics) is a semiconductor manufacturer specializing in high-reliability analog and mixed-signal ICs for industrial, aerospace, and computing applications.

The IS82C59A product line was engineered to deliver CMOS power efficiency and timing precision in legacy microprocessor interrupt management-targeting system designers modernizing 8080/8086/80286 architectures while maintaining full software and hardware compatibility.

FAQ

What is the maximum operating frequency of the IS82C59A-12Z96?

The IS82C59A-12Z96 is rated for a maximum clock frequency of 12.5MHz. This allows "no wait-state" operation with 12.5MHz 80C286 processors and ensures full timing compliance across its entire specified temperature range (−40°C to +85°C). The "-12" suffix explicitly denotes the 12.5MHz speed grade.

Is the IS82C59A-12Z96 pin-compatible with the original NMOS 8259A?

Yes, the IS82C59A-12Z96 is fully pin-compatible with the NMOS 8259A. It maintains identical pinout, signal definitions, timing relationships, and command-set behavior-enabling direct replacement in existing PCB layouts without redesign or firmware changes.

Does the IS82C59A-12Z96 support both 8080/85 and 80C86/88/286 microprocessor modes?

Yes, the IS82C59A-12Z96 supports both modes via the μPM bit in ICW4. When μPM = 0, it operates in 8080/85 mode (three INTA cycles, including CALL opcode 0xCD); when μPM = 1, it operates in 80C86/88/286 mode (two INTA cycles, vector byte only).

What is the purpose of the CAS0–CAS2 pins on the IS82C59A-12Z96?

The CAS0–CAS2 pins form a private cascade bus enabling master/slave configurations. In master mode, they output slave identification codes; in slave mode, they input those codes to determine vector routing. This allows up to eight IS82C59A-12Z96 devices to be cascaded for 64 total interrupt levels without external logic.

How does the IS82C59A-12Z96 handle power consumption in standby mode?

The IS82C59A-12Z96 features a fully static CMOS design with ICCSB ≤ 10μA maximum in standby. This ultra-low quiescent current enables energy-efficient operation in battery-backed or always-on embedded systems where interrupt latency must be preserved without continuous active power draw.