Order this document
by MCM67H618A/D
SEMICONDUCTOR TECHNICAL DATA
MCM67H618A
Product Preview
64K x 18 Bit BurstRAM
Synchronous Fast Static RAM
With Burst Counter and Self–Timed Write
The MCM67H618A is a 1,179,648 bit synchronous fast static random access
memory designed to provide a burstable, high–performance, secondary cache
for the i486 and Pentium microprocessors. It is organized as 65,536 words
of 18 bits, fabricated with Motorola’s high–performance silicon–gate BiCMOS
technology. The device integrates input registers, a 2–bit counter, high speed
SRAM, and high drive capability outputs onto a single monolithic circuit for
reduced parts count implementation of cache data RAM applications. Syn-
chronous design allows precise cycle control with the use of an external clock
(K). BiCMOS circuitry reduces the overall power consumption of the integrated
functions for greater reliability.
FN PACKAGE
PLASTIC
CASE 778–02
PIN ASSIGNMENT
7
6
5
4
3
2
1 52 51 50 49 48 47
46
Addresses (A0 – A15), data inputs (D0 – D17), and all control signals except
output enable (G) are clock (K) controlled through positive–edge–triggered
noninverting registers.
8
9
DQ9
DQ10
DQ8
DQ7
DQ6
45
44
43
42
41
V
V
10
CC
SS
Bursts canbeinitiatedwitheitheraddressstatusprocessor(ADSP) or address
status cache controller (ADSC) input pins. Subsequent burst addresses can be
generated internally by the MCM67H618A (burst sequence imitates that of the
i486 and Pentium) and controlled by the burst address advance (ADV) input pin.
The following pages provide more detailed information on burst controls.
Write cycles are internally self–timed and are initiated by the rising edge of the
clock (K) input. This feature eliminates complex off–chip write pulse generation
and provides increased flexibility for incoming signals.
11
12
13
14
15
V
CC
DQ11
DQ12
DQ13
DQ14
V
SS
DQ5
40 DQ4
39 DQ3
38 DQ2
V
16
17
SS
V
37
V
V
CC
SS
CC
DQ15
18
36
Dual write enables (LW and UW) are provided to allow individually writeable DQ16 19
35 DQ1
34 DQ0
DQ17
20
bytes. LW controls DQ0 – DQ8 (the lower bits), while UW controls DQ9 – DQ17
(the upper bits).
21 22 23 24 25 26 27 28 29 30 31 32 33
This device is ideally suited for systems that require wide data bus widths and
cache memory. See Figure 2 for applications information.
•
•
•
•
•
•
•
•
•
•
•
Single 5 V ± 5% Power Supply
Fast Access Times: 9/10/12 ns Max
Byte Writeable via Dual Write Enables
Internal Input Registers (Address, Data, Control)
Internally Self–Timed Write Cycle
ADSP, ADSC, and ADV Burst Control Pins
Asynchronous Output Enable Controlled Three–State Outputs
Common Data Inputs and Data Outputs
3.3 V I/O Compatible
High Board Density 52–Lead PLCC Package
ADSP Disabled with Chip Enable (E) – Supports Address Pipelining
PIN NAMES
A0 – A15 . . . . . . . . . . . . . . . . Address Inputs
K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clock
ADV . . . . . . . . . . . . Burst Address Advance
LW . . . . . . . . . . . . Lower Byte Write Enable
UW . . . . . . . . . . . . Upper Byte Write Enable
ADSC . . . . . . . . . Controller Address Status
ADSP . . . . . . . . . Processor Address Status
E . . . . . . . . . . . . . . . . . . . . . . . . . Chip Enable
G . . . . . . . . . . . . . . . . . . . . . . Output Enable
DQ0 – DQ17 . . . . . . . . . . Data Input/Output
V
CC
V
SS
. . . . . . . . . . . . . . . . + 5 V Power Supply
. . . . . . . . . . . . . . . . . . . . . . . . . . Ground
All power supply and ground pins must be
connectedforproperoperationofthedevice.
BurstRAM is a trademark of Motorola, Inc.
i486 and Pentium are trademarks of Intel Corp.
This document contains information on a product under development. Motorola reserves the right to change or discontinue this product without notice.
REV 1
5/95
Motorola, Inc. 1994
MOTOROLA FAST SRAM
MCM67H618A
1