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IDT70V7339S
High-Speed 512K x 18 Synchronous Bank-Switchable Dual-Port Static RAM Industrial and Commercial Temperature Ranges
Functional Description
The IDT70V7339 is a high-speed 512Kx18 (9 Mbit) synchronous
Bank-Switchable Dual-Ported SRAM organized into 64 independent
8Kx18 banks. Based on a standard SRAM core instead of a traditional true
dual-port memory core, this bank-switchable device offers the benefits of
increased density and lower cost-per-bit while retaining many of the
features of true dual-ports. These features include simultaneous, random
access to the shared array, separate clocks per port, 166 MHz operating
speed, full-boundary counters, and pinouts compatible with the IDT70V3319
(256Kx18) dual-port family.
The two ports are permitted independent, simultaneous access into
separate banks within the shared array. Access by the ports into specific
banks are controlled by the bank address pins under the user's direct
control: each port can access any bank of memory with the shared array
that is not currently being accessed by the opposite port (i.e., BA0L - BA5L
≠ BA0R - BA5R). In the event that both ports try to access the same bank
at the same time, neither access will be valid, and data at the two specific
addresses targeted by the ports within that bank may be corrupted (in the
case that either or both ports are writing) or may result in invalid output (in
the case that both ports are trying to read).
The IDT70V7339 provides a true synchronous Dual-Port Static RAM
interface. Registered inputs provide minimal setup and hold times on
address, data and all critical control inputs.
An asynchronous output enable is provided to ease asynchronous
bus interfacing. Counter enable inputs are also provided to stall the
operation of the address counters for fast interleaved memory applications.
A HIGH on CE0 or a LOW on CE1 for one clock cycle will power down
the internal circuitry on each port (individually controlled) to reduce static
power consumption. Dual chip enables allow easier banking of multiple
IDT70V7339s for depth expansion configurations. Two cycles are
required with CE0 LOW and CE1 HIGH to read valid data on the outputs.
Depth and Width Expansion
The IDT70V7339 features dual chip enables (refer to Truth
Table I) in order to facilitate rapid and simple depth expansion with no
requirements for external logic. Figure 4 illustrates how to control the
various chip enables in order to expand two devices in depth.
The IDT70V7339 can also be used in applications requiring expanded
width, as indicated in Figure 4. Through combining the control signals, the
devices can be grouped as necessary to accommodate applications
needing 36-bits or wider.
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IDT70V7339
CE0
CE1
CE1
CE0
CE0
CE1
BA6
(1)
CE1
CE0
VDD VDD
IDT70V7339
IDT70V7339
IDT70V7339
Control Inputs
Control Inputs
Control Inputs
Control Inputs BE,
R/W,
OE,
CLK,
ADS,
REPEAT,
CNTEN
Figure 4. Depth and Width Expansion with IDT70V7339
NOTE:
1. In the case of depth expansion, the additional address pin logically serves as an extension of the bank address. Accesses by the ports into specific banks are
controlled by the bank address pins under the user's direct control: each port can access any bank of memory within the shared array that is not currently
being accessed by the opposite port (i.e., BA0L - BA6L ≠ BA0R - BA6R). In the event that both ports try to access the same bank at the same time, neither
access will be valid, and data at the two specific addresses targeted by the parts within that bank may be corrupted (in the case that either or both parts are
writing) or may result in invalid output (in the case that both ports are trying to read).