GS8170LW36 Datasheet, PDF (8/27 Pages) GSI Technology – 18Mb sigma 1x1Lp CMOS I/O Late Write SigmaRAM

GS8170LW36/72C-333/300/250/200
Burst Order
The burst address counter wraps around to its initial state after four internal addresses (the loaded address and three more) have
been accessed. SigmaRAMs always count in linear burst order.
Linear Burst Order
A[1:0]
1st address
00
01
10
11
2nd address
01
10
11
00
3rd address
10
11
00
01
4th address
11
00
01
10
Note:
The burst counter wraps to initial state on the 5th rising edge of clock.
Echo Clock
ΣRAMs feature Echo Clocks, CQ1, CQ2, CQ1, and CQ2 that track the performance of the output drivers. The Echo Clocks are
delayed copies of the main RAM clock, CK. Echo Clocks are designed to track changes in output driver delays due to variance in
die temperature and supply voltage. The Echo Clocks are designed to fire with the rest of the data output drivers. SigmaRAMs
provide both in-phase, or true, Echo Clock outputs (CQ1 and CQ2) and inverted Echo Clock outputs (CQ1 and CQ2).
It should be noted that deselection of the RAM via E2 and E3 also deselects the Echo Clock output drivers. The deselection of
Echo Clock drivers is always pipelined to the same degree as output data. Deselection of the RAM via E1 does not deactivate the
Echo Clocks.
Programmable Enables
ΣRAMs feature two user-programmable chip enable inputs, E2 and E3. The sense of the inputs, whether they function as active
low or active high inputs, is determined by the state of the programming inputs, EP2 and EP3. For example, if EP2 is held at V_DD,
E2 functions as an active high enable. If EP2 is held to V_SS, E2 functions as an active low chip enable input.
Programmability of E2 and E3 allows four banks of depth expansion to be accomplished with no additional logic. By programming
the enable inputs of four SRAMs in binary sequence (00, 01, 10, 11) and driving the enable inputs with two address inputs, four
SRAMs can be made to look like one larger RAM to the system.
Rev: 2.03 1/2005
8/27
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
© 2002, GSI Technology, Inc.