Microchip Technology ATF1508AS-7JC84

Overview

ATF1508AS-7JC84 from Atmel (now Microchip) is a high-density, electrically-erasable Complex Programmable Logic Device (CPLD) with 128 macrocells, 5 product terms per macrocell (expandable to 40), 7.5 ns pin-to-pin delay, and support for 125 MHz registered operation. It features JTAG boundary-scan (IEEE 1149.1), in-system programmability, PCI compliance, and dual-voltage I/O (3.3 V or 5.0 V) - deployed in industrial control logic, legacy bus interface adaptation, and FPGA companion glue logic.

For engineers reviewing the ATF1508AS-7JC84 datasheet, ATF1508AS-7JC84 pinout, ATF1508AS-7JC84 application, or ATF1508AS-7JC84 equivalent, key selection considerations include its 84-lead PLCC package, 128-macrocell architecture with buried feedback routing, programmable slew rate and open-collector outputs, power-down mode via PD1/PD2 pins, and compatibility with 3.3 V/5.0 V mixed-signaling systems.

Technical Context

The ATF1508AS-7JC84 implements a hierarchical CPLD architecture with global and regional buses: all 128 macrocells feed a shared global bus, while each generates a foldback term routed to a 16-macrocell regional bus. Its switch matrix selects up to 40 signals from the global bus per logic block, enabling high-fan-in sum-of-products synthesis.

Each macrocell supports D/T/latch flip-flops with individually selectable clock (GCLK or product-term), asynchronous reset/preset (GCLEAR or product-term), and output enable sourced from dedicated OE pins or I/O subsets. Three global clock pins (GCLK1–GCLK3), ITD circuits on clocks/inputs/I/O, and transparent-latch mode further define its timing and control flexibility.

Key Specifications

Pinout & Package

ATF1508AS-7JC84 is packaged in an 84-lead Plastic Leaded Chip Carrier (PLCC), surface-mount, hermetically sealed with J-lead geometry. The package supports reflow soldering and offers mechanical robustness for industrial temperature operation (–40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar CPLD-based glue logic applications.

Compared with XCR3256XL-10TQ144I and LC4256ZE-7TN144C, ATF1508AS-7JC84 uniquely supports mixed 3.3 V/5 V I/O, JTAG boundary-scan, and PCI-compliant drivers - making it irreplaceable in industrial retrofits and mixed-voltage board designs where pin-compatible alternatives do not exist.

Availability

ATF1508AS-7JC84 is available at Aetrix Electronics and suitable for industrial PLC expansion, legacy bus interface adaptation, and FPGA companion logic requiring stable component supply across extended product lifecycles.

Supply support for ATF1508AS-7JC84 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

Microchip Technology (formerly Atmel) is a leading provider of microcontrollers, analog components, and programmable logic solutions, serving industrial, automotive, and communications markets with high-reliability silicon.

The ATF1508AS family was designed for high-density, in-system programmable glue logic in mixed-voltage, timing-critical embedded systems - emphasizing PCI compliance, JTAG testability, and long-term nonvolatile configuration retention.

FAQ

What is the operating temperature range for ATF1508AS-7JC84?

The ATF1508AS-7JC84 is rated for industrial temperature operation from –40°C to +85°C. This specification is validated per the device's DC and AC operating conditions table and applies to the 84-lead PLCC package variant. The "-7" speed grade and "JC" suffix confirm industrial-grade qualification. ATF1508AS-7JC84 maintains full functionality across this range, including JTAG boundary-scan and in-system programming capability.

Does ATF1508AS-7JC84 support both 3.3 V and 5.0 V I/O simultaneously?

Yes, ATF1508AS-7JC84 supports mixed-voltage I/O via separate VCCIO and VCCINT supplies: VCCINT must be 5.0 V for core logic, while VCCIO pins may be independently set to either 3.3 V or 5.0 V. This allows individual I/O banks to interface with 3.3 V or 5.0 V peripherals on the same device. ATF1508AS-7JC84 achieves this without level shifters, maintaining signal integrity and timing predictability.

How does the power-down mode function on ATF1508AS-7JC84?

ATF1508AS-7JC84 enters power-down mode when either PD1 or PD2 pin is driven high, reducing supply current to under 10 mA. During this state, all internal logic and output states are latched and held - registered outputs remain valid, and tri-state outputs retain high-Z status. Input sampling is suspended except for the PD pin itself. ATF1508AS-7JC84 resumes normal operation within 1 µs after PD returns low.

Is ATF1508AS-7JC84 compatible with IEEE 1149.1 boundary-scan testing?

Yes, ATF1508AS-7JC84 fully complies with IEEE Std. 1149.1-1990 and 1149.1a-1993 for boundary-scan testing. It includes dedicated TDI, TDO, TMS, and TCK pins with integrated boundary-scan cells on all I/O and input pins. BSDL models are available from Microchip for test vector generation. ATF1508AS-7JC84 supports SAMPLE/PRELOAD, EXTEST, BYPASS, and IDCODE instructions - no TRST pin is required due to automatic TAP reset at power-up.

Can ATF1508AS-7JC84 be programmed in-system without removing it from the PCB?

Yes, ATF1508AS-7JC84 supports full in-system programming (ISP) via its 4-pin JTAG interface using standard IEEE 1149.1 protocols. Programming is performed with 5 V TTL-level signals and requires no device removal or socketing. ATF1508AS-7JC84 ships erased and ready for ISP; SVF files generated by Microchip tools enable ATE integration. JTAG pins may be repurposed as general I/O if ISP/BST is disabled in the design.