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SEMICONDUCTOR TECHNICAL DATA
MCM67H618B
Advance Information
64K x 18 Bit BurstRAM
Synchronous Fast Static RAM
With Burst Counter and Self–Timed Write
The MCM67H618B 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 DQ8
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.
DQ9
DQ10
8
9
10
11
45 DQ7
44 DQ6
V
V
CC
SS
Bursts can be initiated with either address status processor (ADSP)
or address status cache controller (ADSC) input pins. Subsequent
burst addresses can be generated internally by the MCM67H618B
(burst sequence imitates that of the i486 and Pentium) and controlled
by the burst address advance (ADV) input pin. The following pages pro-
vide more detailed information on burst controls.
43
42
V
V
CC
SS
DQ11 12
DQ12 13
DQ13 14
DQ14 15
41 DQ5
40 DQ4
39 DQ3
38 DQ2
V
16
17
SS
CC
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.
V
37
36
V
V
SS
CC
DQ15 18
DQ16 19
DQ17 20
35 DQ1
34 DQ0
21 22 23 24 25 26 27 28 29 30 31 32 33
Dual write enables (LW and UW) are provided to allow individually
writeable bytes. LW controls DQ0 – DQ8 (the lower bits), while UW
controls DQ9 – DQ17 (the upper bits).
This device is ideally suited for systems that require wide data bus
widths and cache memory. See Figure 2 for applications information.
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
•
•
•
•
•
•
•
•
•
•
•
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
V
V
. . . . . . . . . . . . . . . . + 5 V Power Supply
. . . . . . . . . . . . . . . . . . . . . . . . . . Ground
CC
SS
All power supply and ground pins must be con-
nected for proper operation of the device.
i486 and Pentium are trademarks of Intel Corp.
This document contains information on a new product. Specifications and information herein are subject to change without notice.
REV 1
7/15/97
Motorola, Inc. 1997
MOTOROLA FAST SRAM
MCM67H618B
1