Renesas CS82C59A-12Z

Overview

CS82C59A-12Z from Intersil is a CMOS Priority Interrupt Controller designed to offload interrupt management from 8080/85, 8086/88, and 80C286-based microcomputer systems. It handles up to eight vectored priority interrupt sources, supports cascading to 64 levels, operates at 12.5 MHz, features fully static CMOS design, and uses a single +5 V supply.

For engineers reviewing the CS82C59A-12Z datasheet, CS82C59A-12Z pinout, CS82C59A-12Z application, or CS82C59A-12Z equivalent, key selection criteria include its 28-pin PLCC Pb-free package, edge- or level-triggered IR inputs, programmable priority modes (fully nested, rotating, special mask), compatibility with both 8080/85 and 80C86/88/286 interrupt response protocols, and low-power operation (ICCOP ≤ 1 mA/MHz).

Technical Context

The CS82C59A-12Z implements a three-register architecture - Interrupt Request Register (IRR), In-Service Register (ISR), and Interrupt Mask Register (IMR) - coordinated by dedicated priority resolver logic. Its read/write control logic accepts Initialization Command Words (ICW1–ICW4) and Operation Command Words (OCW1–OCW3) to configure system mode (μPM), cascade topology, vector addressing, and masking behavior.

It supports dual interrupt response formats: three-pulse 8080/85 mode (with CALL opcode and 16-bit vector bytes) and two-pulse 80C86/88/286 mode (direct 8-bit interrupt code). The SP/EN pin serves dual roles - slave program input or buffer enable - and CAS0–CAS2 lines enable master/slave identification in cascaded configurations without external logic.

Key Specifications

Pinout & Package

CS82C59A-12Z is housed in a 28-lead plastic-leaded chip carrier (PLCC) package with J-lead configuration, RoHS-compliant matte tin plating, and JEDEC-standard outline N28.45. It is rated for commercial temperature range (0°C to +70°C) and supports wave-solder and reflow assembly per IPC/JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CS82C59AZ, the CS82C59A-12Z guarantees 12.5 MHz operation and is optimized for commercial-temperature embedded systems; compared with IS82C59A-12Z, it trades extended temperature range for lower cost and tighter qualification scope - making it ideal for cost-sensitive, thermally stable industrial control panels.

Availability

CS82C59A-12Z is available at Aetrix Electronics and suitable for industrial PLC backplanes, legacy x86 embedded controllers, and medical diagnostic instruments requiring stable component supply, long-term obsolescence mitigation, and RoHS-compliant manufacturing.

Supply support for CS82C59A-12Z 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-performance analog and mixed-signal ICs for industrial, communications, and computing markets.

The 82C59A family was developed to provide CMOS-based, low-power, pin-compatible replacements for the industry-standard NMOS 8259A interrupt controller in 1980s–1990s microcomputer systems.

FAQ

What is the operating temperature range for CS82C59A-12Z?

The CS82C59A-12Z is specified for commercial temperature operation from 0°C to +70°C. This range aligns with standard industrial control and embedded computing environments where ambient thermal management is controlled. It is not rated for extended industrial (−40°C to +85°C) or military-grade operation - for those requirements, the IS82C59A-12Z variant should be selected instead. All electrical parameters in the FN2784 datasheet are guaranteed within this 0°C to +70°C window.

Is CS82C59A-12Z pin-compatible with the original NMOS 8259A?

Yes, CS82C59A-12Z is fully pin-compatible with the NMOS 8259A. Its 28-pin PLCC footprint, signal assignments (including IR0–IR7, INT, INTA, CS, RD, WR, A0, D7–D0, CAS0–CAS2, SP/EN), and DC electrical characteristics (VIL/VIH, VOL/VOH) match the legacy device. This enables direct replacement in existing designs without PCB modification - a key feature emphasized in the datasheet's "Pin Compatible with NMOS 8259A" bullet.

How does CS82C59A-12Z handle interrupt vectoring in 8086/88 systems?

In 80C86/88/286 mode (μPM = 1), CS82C59A-12Z delivers an 8-bit interrupt vector code on D7–D0 during the second INTA pulse - no CALL opcode is issued. The vector byte encodes the interrupt level (IR0–IR7) in bits D2–D0 and system-specific tag bits (T7–T3) in D7–D3. This matches the 8086's interrupt response protocol exactly and eliminates the need for software decoding of separate address bytes, streamlining ISR dispatch.

Can CS82C59A-12Z be used in cascaded configurations?

Yes, CS82C59A-12Z supports seamless cascading to up to 64 interrupt levels using only the CAS0–CAS2 and SP/EN pins - no external logic required. In master configuration, CAS0–CAS2 output the slave ID; in slave configuration, they input the master-assigned ID. ICW3 configures the mapping, and ICW4 sets SFNM for special fully nested mode, ensuring correct priority inheritance across tiers.

What power supply requirements does CS82C59A-12Z have?

CS82C59A-12Z operates from a single +5 V ±10% supply (VCC = Pin 28, GND = Pin 14). It draws ≤10 μA in standby (ICCSB) and ≤1 mA per MHz during active operation (ICCOP), making it significantly more efficient than NMOS predecessors. A 0.1 μF ceramic decoupling capacitor between VCC and GND is mandatory per the datasheet to suppress switching noise and ensure stable register operation.