MCM67J618B Datasheet, PDF (1/12 Pages) Motorola, Inc – 64K x 18 Bit BurstRAM Synchronous Fast Static RAM

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SEMICONDUCTOR TECHNICAL DATA
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64K x 18 Bit BurstRAM™
Synchronous Fast Static RAM
With Burst Counter and Registered Outputs
MCM67J618B
The MCM67J618B 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-
chronous design allows precise cycle control with the use of an external clock (K).
BiCMOS circuitry reduces the overall power consumption of the integrated func-
tions for greater reliability.
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 MCM67J618B (burst sequence imitates that of the
i486) 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.
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.
• Single 5 V ± 5% Power Supply
DQ9
DQ10
• Fast Access Time/Fast Cycle Time = 5 ns/100 MHz, 7 ns/80 MHz
VCC
• Byte Writeable via Dual Write Enables
VSS
• Internal Input Registers (Address, Data, Control)
DQ11
• Output Registers for Pipelined Applications
DQ12
• Internally Self–Timed Write Cycle
DQ13
• ADSP, ADSC, and ADV Burst Control Pins
• Asynchronous Output Enable Controlled Three–State Outputs
DQ14
VSS
VCC
• Common Data Inputs and Data Outputs
DQ15
• 3.3 V I/O Compatible
DQ16
• High Board Density 52–Lead PLCC Package
DQ17
• ADSP Disabled with Chip Enable (E) — Supports Address Pipelining
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
VCC . . . . . . . . . . . . . . . . + 5 V Power Supply
VSS . . . . . . . . . . . . . . . . . . . . . . . . . . Ground
All power supply and ground pins must be
connected for proper operation of the device.
PIN ASSIGNMENT
7 6 5 4 3 2 1 52 51 50 49 48 47
8
46 DQ8
9
45 DQ7
10
44 DQ6
11
43 VCC
12
42 VSS
13
41 DQ5
14
40 DQ4
15
39 DQ3
16
38 DQ2
17
37 VSS
18
36 VCC
19
35 DQ1
20
34 DQ0
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 new product under development. Motorola reserves the right to change or discontinue this product without notice.
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MCM67J618B
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