A67L83161/A67L83181/
A67L73321/A67L73361 Series
256K X 16/18, 128K X 32/36
Preliminary
Features
n
Fast access time: 10/11/12 ns
(100, 90, 83 MHz)
n
Direct Bus Alternation between READ and WRITE
cycles allows 100% bus utilization
n
Signal +3.3V
±
5% power supply
n
Individual Byte Write control capability
n
Clock enable (
CEN
) pin to enable clock and suspend
operations
n
Clock-controlled and registered address, data and
control signals
n
Registered output for pipelined applications
n
Three separate chip enables allow wide range of
options for CE control, address pipelining
n
Internally self-timed write cycle
n
Selectable BURST mode (Linear or Interleaved)
n
SLEEP mode (ZZ pin) provided
n
Available in 100 pin LQFP package
LVTTL, Flow-through DBA
TM
SRAM
General Description
The AMIC Direct Bus Alternation™ (DBA™) SRAM
family employs high-speed, low-power CMOS designs
using an advanced CMOS process.
The A67L83161, A67L83181, A67L73321, A67L73361
SRAMs integrate a 256K X 16, 256K X 18, 128K X 32 or
128K X 36 SRAM core with advanced synchronous
peripheral circuitry and a 2-bit burst counter. These
SRAMs are optimized for 100 percent bus utilization
without the insertion of any wait cycles during Write-
Read alternation. The positive edge triggered single
clock input (CLK) controls all synchronous inputs
passing through the registers. The synchronous inputs
include all address, all data inputs, active low chip
enable (
CE
), two additional chip enables for easy depth
expansion (CE2,
CE2
), cycle start input (ADV/ LD ),
synchronous clock enable (
CEN
), byte write enables
(
BW1
,
BW2
,
BW3
,
BW4
) and read/write (R/
W
).
Asynchronous inputs include the output enable (
OE
),
clock (CLK), SLEEP mode (ZZ, tied LOW if unused) and
burst mode (MODE). Burst Mode can provide either
interleaved or linear operation, burst operation can be
initiated by synchronous address Advance/Load
(ADV/ LD ) pin in Low state. Subsequent burst address
can be internally generated by the chip and controlled by
the same input pin ADV/ LD in High state.
Write cycles are internally self-time and synchronous
with the rising edge of the clock input and when R/
W
is
Low. The feature simplified the write interface. Individual
Byte enables allow individual bytes to be written.
BW1
controls I/Oa pins;
BW2
controls I/Ob pins;
BW3
controls I/Oc pins; and
BW4
controls I/Od pins. Cycle
types can only be defined when an address is loaded,
i.e., when ADV/ LD is LOW. Parity/ECC bits are only
available on the X18/36 version.
The SRAM operates from a +3.3V power supply, and all
inputs and outputs are LVTTL-compatible. The device is
ideally suited for high bandwidth utilization systems.
PRELIMINARY
(September, 1999, Version 0.1)
1
AMIC Technology, Inc.
DBA and Direct Bus Alternation are trademarks of AMIC Technology, Inc
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