IS42S16400A.pdf

IS42S16400A.pdf

FEATURES
• Clock frequency:166, 133, 100 MHz
• Fully synchronous; all signals referenced to a
positive clock edge
• Internal bank for hiding row access/precharge
• Single 3.3V power supply
• LVTTL interface
• Programmable burst length
– (1, 2, 4, 8, full page)
• Programmable burst sequence:
Sequential/Interleave
• Self refresh modes
• 4096 refresh cycles every 64 ms
• Random column address every clock cycle
• Programmable CAS latency (2, 3 clocks)
• Burst read/write and burst read/single write
operations capability
• Burst termination by burst stop and precharge
command
• Byte controlled by LDQM and UDQM
• Industrial temperature availability
(133MHz, 100MHz)
• Package: 400-mil 54-pin TSOP II,
a lead-free package is available.

GENERAL DESCRIPTION
The 64Mb SDRAM is a high speed CMOS, dynamic
random-access memory designed to operate in 3.3V
memory systems containing 67,108,864 bits. Internally
configured as a quad-bank DRAM with a synchronous
interface. Each 16,777,216-bit bank is organized as 4,096
rows by 256 columns by 16 bits.
The 64Mb SDRAM includes an AUTO REFRESH MODE,
and a power-saving, power-down mode. All signals are
registered on the positive edge of the clock signal, CLK.
All inputs and outputs are LVTTL compatible.
The 64Mb SDRAM has the ability to synchronously burst
data at a high data rate with automatic column-address
generation, the ability to interleave between internal banks
to hide precharge time and the capability to randomly
change column addresses on each clock cycle during
burst access.
A self-timed row precharge initiated at the end of the burst
sequence is available with the AUTO PRECHARGE
function enabled. Precharge one bank while accessing one
of the other three banks will hide the precharge cycles and
provide seamless, high-speed, random-access operation.
SDRAM read and write accesses are burst oriented starting
at a selected location and continuing for a programmed
number of locations in a programmed sequence. The
registration of an ACTIVE command begins accesses,
followed by a READ or WRITE command. The ACTIVE
command in conjunction with address bits registered are
used to select the bank and row to be accessed (BA0, BA1
select the bank; A0-A11 select the row). The READ or
WRITE commands in conjunction with address bits registered
are used to select the starting column location for
the burst access.
Programmable READ or WRITE burst lengths consist of
1, 2, 4 and 8 locations or full page, with a burst terminate
option.