IS61QDB42M18A Datasheet, PDF (1/30 Pages) Integrated Silicon Solution, Inc – Synchronous pipeline read with late write operation

IS61QDB42M18A
IS61QDB41M36A
2Mx18, 1Mx36
36Mb QUAD (Burst 4) SYNCHRONOUS SRAM
FEATURES
DESCRIPTION
JANUARY 2015
 1Mx36 and 2Mx18 configuration available.
 On-chip Delay-Locked Loop (DLL) for wide data
valid window.
 Separate independent read and write ports with
concurrent read and write operations.
 Synchronous pipeline read with late write operation.
 Double Data Rate (DDR) interface for read and
write input ports.
 1.5 cycle read latency.
 Fixed 4-bit burst for read and write operations.
 Clock stop support.
 Two input clocks (K and K#) for address and control
registering at rising edges only.
 Two output clocks (C and C#) for data output control.
 Two echo clocks (CQ and CQ#) that are delivered
simultaneously with data.
 +1.8V core power supply and 1.5, 1.8V VDDQ, used
with 0.75, 0.9V VREF.
 HSTL input and output levels.
 Registered addresses, write and read controls, byte
writes, data in, and data outputs.
 Full data coherency.
 Boundary scan using limited set of JTAG 1149.1
functions.
 Byte write capability.
 Fine ball grid array (FBGA) package:
13mmx15mm and 15mmx17mm body size
165-ball (11 x 15) array
 Programmable impedance output drivers via 5x
user-supplied precision resistor.
The 36Mb IS61QDB41M36A and IS61QDB42M18A are
synchronous, high-performance CMOS static random access
memory (SRAM) devices. These SRAMs have separate I/Os,
eliminating the need for high-speed bus turnaround. The
rising edge of K clock initiates the read/write operation, and
all internal operations are self-timed. Refer to the Timing
Reference Diagram for Truth Table for a description of the
basic operations of these QUAD (Burst of 4) SRAMs.
Read and write addresses are registered on alternating rising
edges of the K clock. Reads and writes are performed in
double data rate. The following are registered internally on
the rising edge of the K clock:
 Read/write address
 Read enable
 Write enable
 Byte writes for burst addresses 1 and 3
 Data-in for burst addresses 1 and 3
The following are registered on the rising edge of the K#
clock:
 Byte writes for burst addresses 2 and 4
 Data-in for burst addresses 2 and 4
Byte writes can change with the corresponding data-in to
enable or disable writes on a per-byte basis. An internal write
buffer enables the data-ins to be registered one cycle after
the write address. The first data-in burst is clocked one cycle
later than the write command signal, and the second burst is
timed to the following rising edge of the K# clock. Two full
clock cycles are required to complete a write operation.
During the burst read operation, the data-outs from the first
and third bursts are updated from output registers of the
second and third rising edges of the C# clock (starting 1.5
cycles later after read command). The data-outs from the
second and fourth bursts are updated with the third and
fourth rising edges of the C clock. The K and K# clocks are
used to time the data-outs whenever the C and C# clocks are
tied high. Two full clock cycles are required to complete a
read operation.
The device is operated with a single +1.8V power supply and
is compatible with HSTL I/O interfaces.
Copyright © 2014 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time
without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to
obtain the latest version of this device specification before relying on any published information and before placing orders for products.
Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can
reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such
applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that:
a.) the risk of injury or damage has been minimized;
b.) the user assume all such risks; and
c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances
Integrated Silicon Solution, Inc.- www.issi.com
1
Rev. B
10/02/2014