EPM7128ELC84-7 CPLD: A Technical Guide to Specs, Pinout, and Programming

In the world of embedded systems maintenance, few components are as iconic—or as critical—as the EPM7128ELC84-7. This chip isn't just a programmable logic device; it is the heartbeat of countless industrial controllers, telecom interface cards, and avionics systems built in the 1990s and early 2000s.

While modern FPGAs dominate new designs, the global MRO (Maintenance, Repair, and Operations) market relies heavily on legacy 5V components like this one. Sourcing and using the EPM7128ELC84-7 today presents a unique set of challenges, particularly regarding programming. Unlike its younger siblings, this chip doesn't always play by modern rules.

This guide is your definitive technical resource. We will decode the EPM7128ELC84-7 datasheet, clarify the vital difference between the "E" and "S" series, and explain exactly what you need to program this PLCC-84 veteran.

1.0 What is the EPM7128ELC84-7? (Datasheet Explained)

The EPM7128ELC84-7 is a high-performance, EEPROM-based Complex Programmable Logic Device (CPLD). It was manufactured by Altera (now Intel) as part of the legendary MAX 7000 family.

1.1 The Altera MAX 7000 Family: The King of 5V Logic

The MAX 7000 family was designed to provide high-speed logic integration for 5-volt systems. Unlike FPGAs, which lose their configuration when power is cut, CPLDs like the EPM7128 use non-volatile EEPROM technology. This means they are "instant-on"—the logic is ready the moment power is applied, making them perfect for critical boot logic, address decoding, and bus interfacing.

1.2 Decoding the Part Number: 128 Macrocells, PLCC-84

Every character in the part number tells a specific technical story: * **EPM7:** Device Family (MAX 7000). * **128:** Logic Density (**128 Macrocells**). * **E:** Enhanced features (but notably, usually *not* In-System Programmable via JTAG like the "S" series). * **LC:** Package Type (**PLCC**, Plastic Leaded Chip Carrier). * **84:** Pin Count (**84 pins**). * **-7:** Speed Grade (**7.5 ns** propagation delay—this is the fastest speed grade for this device).

1.3 EPM7128E vs. EPM7128S: The Critical Programming Difference

This is the most common pitfall for engineers attempting a repair. * **EPM7128S:** The "S" stands for In-System Programmable (ISP). You can program this chip while it is soldered to the board using a standard JTAG cable (USB-Blaster). * **EPM7128E:** The **EPM7128ELC84-7** belongs to the "E" series. These devices generally **DO NOT** support ISP via JTAG. They must be programmed in a socket using a dedicated hardware programmer *before* being installed on the board.

Warning: Do not assume you can plug a USB-Blaster into a board with an EPM7128E and program it. Unless the board has specific high-voltage programming logic, it won't work.

2.0 EPM7128ELC84-7 Key Technical Specifications

When validating this part for a replacement, these are the hard numbers you need.

2.1 Core Logic Specs (Macrocells, Gates, Speed)

Feature	Specification
Family	Altera MAX 7000 (E-Series)
Macrocells	128
Usable Gates	~2,500
Logic Array Blocks (LABs)	8
Max User I/O	68 (in PLCC-84 package)
Propagation Delay (tPD)	7.5 ns (Speed Grade -7)
Frequency (fCNT)	125 MHz

2.2 Operating Voltage: True 5.0V Operation

The EPM7128ELC84-7 is a **native 5V device**. * **Supply Voltage (VCC):** 5.0V ±5%. * **Input Levels:** TTL/CMOS compatible (5V tolerant). * **Output Levels:** 5V TTL/CMOS.

This 5V capability is why the chip is still so valuable. Modern CPLDs operate at 3.3V, 2.5V, or 1.8V and cannot directly drive the legacy 5V buses found in older equipment without complex level shifters.

3.0 Pinout and Package Details (PLCC-84)

The PLCC-84 package is a square, plastic chip carrier with "J" leads tucked underneath the edges. It was a standard for socketed chips in the 90s.

3.1 Understanding the PLCC-84 Package

* **Shape:** Square. * **Pin Counting:** Pin 1 is located at the center of the side with the beveled (chamfered) corner. Pins count counter-clockwise. * **Socket:** This chip is almost always installed in a through-hole or SMT socket, which is fortunate because it allows for easy removal for programming.

3.2 Key Pin Functions: Power and I/O

* **VCCINT / VCCIO:** Power pins (5V). All VCC pins must be connected to a clean 5V source. * **GND:** Ground pins. * **I/O Pins:** User-configurable Input/Output pins. * **GCLK1:** Global Clock input. Critical for synchronous logic designs. * **GCLR:** Global Clear. Used to reset all registers in the device.

4.0 Programming and Maintenance Guide

If you have a blank EPM7128ELC84-7 and a .POF file, here is how you get the logic into the chip.

4.1 How to Program the "E" Series (Hardware Programmer Required)

Since the "E" series is not ISP-capable via standard JTAG: 1. **Remove the Chip:** If the chip is not in a socket, you must desolder it. 2. **Use a Universal Programmer:** You need a hardware programmer from brands like **Data I/O**, **BP Microsystems**, **Xeltek**, or **Elnec**. 3. **Socket Adapter:** You will likely need a specific **PLCC-84 adapter** for your programmer to physically hold the chip. 4. **Load File:** Load your `.pof` (Programmer Object File) into the programmer software and burn the device.

4.2 Required Software: Legacy Quartus II or MAX+PLUS II

To edit the logic or generate a new programming file, you need legacy software. * **MAX+PLUS II:** The original software for this era. It works best on Windows 98/XP. * **Quartus II (Web Edition):** Certain older versions of Quartus II (e.g., version 9.0 or 9.1) still support the MAX 7000 family. Newer versions (Quartus Prime) **do not** support these legacy chips.

4.3 Obsolescence and Replacement Strategy

The **EPM7128ELC84-7** is obsolete (EOL). * **Direct Replacement:** Sourcing "New Old Stock" (NOS) from specialized distributors like **AichipLink** is the most reliable path for repair. * **Functional Equivalent:** If you can modify the board wiring, the **EPM7128SLC84-7** ("S" series) is functionally very similar but adds ISP capability. However, verify timing and pinout compatibility carefully.

In Conclusion

The EPM7128ELC84-7 remains a vital component for the longevity of mission-critical 5V systems. Its combination of 128 macrocells, high speed (7.5ns), and robust PLCC package makes it irreplaceable in many legacy applications. However, success with this chip requires understanding its programming limitations—specifically the need for a hardware programmer rather than a simple USB cable.

If you are tasked with repairing a system that relies on this CPLD, don't risk using unverified parts or incorrect programming methods. Browse our inventory of Altera CPLDs or contact AichipLink today to secure the authentic components you need to get your equipment back online.

 

 

 

 

 

Written by Jack Elliott from AIChipLink.

 

AIChipLink, one of the fastest-growing global independent electronic   components distributors in the world, offers millions of products from thousands of manufacturers, and many of our in-stock parts is available to ship same day.

 

We mainly source and distribute integrated circuit (IC) products of brands such as Broadcom, Microchip, Texas Instruments, Infineon, NXP, Analog Devices, Qualcomm, Intel, etc., which are widely used in communication & network, telecom, industrial control, new energy and automotive electronics. 

 

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