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AS7C34098A
2/12/04,v. 1.2 Alliance Semiconductor P. 3 of 12
Functional description
The AS7C34098A is a high-performance CMOS 4,194,304-bit Static Random Access Memory (SRAM) device organized as
262,144 words × 16 bits. It is designed for memory applications where fast data access, low power, and simple interfacing are
desired.
Equal address access and cycle times (tAA, tRC, tWC) of 10/12/15/20 ns with output enable access times (tOE) of 4/5/6/7 ns are
ideal for high-performance applications. The chip enable input CE permits easy memory expansion with multiple-bank
memory systems.
When CE is high the device enters standby mode. The device is guaranteed not to exceed 18mW power consumption in CMOS
standby mode. A write cycle is accomplished by asserting write enable (WE) and chip enable (CE). Data on the input pins I/
O1–I/O16 is written on the rising edge of WE (write cycle 1) or CE (write cycle 2). To avoid bus contention, external devices
should drive I/O pins only after outputs have been disabled with output enable (OE) or write enable (WE).
A read cycle is accomplished by asserting output enable (OE) and chip enable (CE), with write enable (WE) high. The chip
drives I/O pins with the data word referenced by the input address. When either chip enable or output enable is inactive, or
write enable is active, output drivers stay in high-impedance mode.
The device provides multiple center power and ground pins, and separate byte enable controls, allowing individual bytes to be
written and read. LB controls the lower bits, I/O1–I/O8, and UB controls the higher bits, I/O9–I/O16.
All chip inputs and outputs are TTL- and CMOS-compatible, and operation is for 3.3V (AS7C34098A) supply. The device is
available in the JEDEC standard 400-mL, 44-pin SOJ, TSOP 2 and also with 48B uBGA package with 6 X 9mm external
dimension..
Note: Stresses greater than those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and
functional operation of the device at these or any other conditions outside those indicated in the operational sections of this specification is not implied.
Exposure to absolute maximum rating conditions for extended periods may affect reliability.
Absolute maximum ratings
Parameter Symbol Min Max Unit
Voltage on VCC relative to GND Vt1 –0.50 +5.0 V
Voltage on any pin relative to GND Vt2 –0.50 VCC +0.50 V
Power dissipation PD–1.5W
Storage temperature (plastic) Tstg –65 +150 °C
Ambient temperature with VCC applied Tbias –55 +125 °C
DC current into outputs (low) IOUT –±20mA
Truth table
CE WE OE LB UB I/O1–I/O8 I/O9–I/O16 Mode
HXXXX High Z High Z Standby (I
SB, ISB1)
LHHXX
High Z High Z Output disable (ICC)
LXXHH
LHL
LH D
OUT High Z
Read (ICC)H L High Z DOUT
LL D
OUT DOUT
LLX
LH D
IN High Z
Write (ICC)
H L High Z DIN
LL D
IN DIN
Key: X = Don’t care, L = Low, H = High.