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SEMICONDUCTOR TECHNICAL DATA
MCM67C618B
Product Preview
64K x 18 Bit BurstRAM
Synchronous Fast Static RAM
With Burst Counter and Registered Outputs
The MCM67C618B is a 1,179,648 bit synchronous 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 registered output drivers onto a single monolithic circuit
for reduced parts count implementation of cache data RAM applications. Syn-
chronousdesignallowsprecisecyclecontrolwiththeuseofanexternalclock(K).
BiCMOS circuitry reduces the overall power consumption of the integrated
functions for greater reliability.
FN PACKAGE
PLASTIC
CASE 778–02
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
Addresses (A0 – A15), data inputs (D0 – D17), and all control signals except
output enable (G) are clock (K) controlled through positive–edge–triggered non-
inverting registers.
This device contains output registers for pipeline operations. At the rising edge
of K, the RAM provides the output data from the previous cycle.
Output enable (G) is asynchronous for maximum system design flexibility.
Burst 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 MCM67C618B (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.
V
CC
V
SS
. . . . . . . . . . . . . . . . + 5 V Power Supply
. . . . . . . . . . . . . . . . . . . . . . . . . . Ground
NC . . . . . . . . . . . . . . . . . . . . . No Connection
All power supply and ground pins must be
connected for proper operation of the device.
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).
PIN ASSIGNMENT
This device is ideally suited for systems that require wide data bus widths and
cache memory. See Figure 2 for applications information.
7
6
5
4
3
2
1 52 51 50 49 48 47
46
•
•
•
•
•
•
•
•
•
•
•
Single 5 V ± 5% Power Supply
Fast Access Time/Fast Cycle Time = 5 ns/100 MHz, 7 ns/80 MHz
Byte Writeable via Dual Write Enables
Internal Input Registers (Address, Data, Control)
Output Registers for Pipelined Applications
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
8
9
DQ9
DQ10
DQ8
DQ7
DQ6
45
44
43
V
V
10
CC
SS
11
V
CC
DQ11
DQ12
DQ13
12
13
14
42
41
40
V
DQ5
DQ4
SS
DQ14
15
16
17
18
19
20
39
38
37
36
35
34
DQ3
DQ2
V
SS
V
V
CC
SS
DQ15
DQ16
DQ17
V
CC
DQ1
DQ0
High Board Density 52–Lead PLCC Package
21 22 23 24 25 26 27 28 29 30 31 32 33
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.
7/96
Motorola, Inc. 1996
MOTOROLA FAST SRAM
MCM67C618B
1
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