Features: · Dynamic random access memory 65536 x 4 bits manufactured using a CMOS technology·RAS access times 70 ns/80 ns· TTL-compatible· Three-state outputs bidirectional· 256 refresh cycles 4 ms refresh cycle time· FAST PAGE MODE· Operating modes: Read, Write, Read - Write, RAS only Refresh, Hi...
UD61464: Features: · Dynamic random access memory 65536 x 4 bits manufactured using a CMOS technology·RAS access times 70 ns/80 ns· TTL-compatible· Three-state outputs bidirectional· 256 refresh cycles 4 ms ...
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Absolute Maximum Ratings |
Symbol |
Min. |
Max. |
Unit |
Power Supply Voltage Input Voltage 1) Output Voltage 1) Output Current 1a) Power Dissipation Operating Temperature Storage Temperature |
VCC VI VO IO PD Ta Tstg |
-0.5 -1.0 -1.0 -50 0 -55 |
7.0 7.0 7.0 50 1 70 125 |
V V V mA W °C °C |
Addressing
The UD61464 is a dynamic random access memory organized 65536 words by 4 bits. FPM facilitates faster data operation with predefined row address. Via 8 address inputs the 16 address bits are transmitted into the internal address memories in a time-multiplex operation. The falling RASedge takes over the row address.
After the UD61464 row address hold time the column address can be applied. The bit pattern that is available at the address outputs during the set-up time and after the falling edge of CAS is interpreted as row address. During Write the column address is taken over with the falling edge of the control signal CAS, or W, whichever becomes active as the last. The selection of one or more memory circuits can be made via the RAS input.
Read-Write-Control
The choice between Read or Write cycle is made at the W input. UD61464 HIGH at the W input causes a Read cycle, meanwhile LOW leads to a Write cycle.
Both UD61464 CAS-controlled and W-controlled Write cycles are possible with activated RAS signal.