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DP8422V Datasheet microCMOS Programmable 256k/1M/4M Dynamic RAM Controller/Drivers

Manufacturer: National Semiconductor (now Texas Instruments)

Download the DP8422V datasheet PDF. This datasheet also includes the DP84T22 variant, as both parts are published together in a single manufacturer document.

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Note: The manufacturer provides a single datasheet file (DP84T22_NationalSemiconductor.pdf) that lists specifications for multiple related part numbers.

General Description

The DP8420V 21V 22V-33 DP84T22-25 dynamic RAM controllers provide a low cost single chip interface between dynamic RAM and all 8- 16- and 32-bit systems The DP8420V 21V 22V-33 DP84T22-25 generate all the required access control signal timing for DRAMs An on-chip refresh request clock is used to automatically refresh the DRAM array Refreshes and accesses are arbitrated on chip If necessary a WAIT or DTACK output inserts wait states into system access cycles including burst mode accesses RAS low time during refreshes and RAS precharge time after refreshes and back to back accesses are guaranteed through the insertion of wait states Separate on-chip precharge counters for each RAS output can be used for memory interleaving to avoid delayed back to back accesses because of precharge An additional

Overview

DP8420V 21V 22V-33 DP84T22-25 microCMOS Programmable 256k 1M 4M Dynamic RAM Controller Drivers May 1992 DP8420V 21V 22V-33 DP84T22-25 microCMOS Programmable 256k 1M 4M Dynamic RAM Controller.

Key Features

  • Y Y Y Y Y Y Y Y Y Y On chip high precision delay line to guarantee critical DRAM access timing parameters microCMOS process for low power High capacitance drivers for RAS CAS WE and DRAM address on chip On chip support for nibble page and static column DRAMs TRI-STATE outputs (DP84T22 only) Byte enable signals on chip allow byte writing in a word size up to 32 bits with no external logic Selection of controller speeds 25 MHz and 33 MHz On board Port A Port B (DP8422V DP84T22 only) refresh.

More Datasheets from National Semiconductor (now Texas Instruments)

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