GVT71256DA18

The Galvantech Synchronous Burst SRAM familyemploys high-speed, low power CMOS designs using advanced triple-layer polysilicon, double-layer metal technology. Each memory cell consists of four transistors and two high valued resistors.

The GVT71128DA36 and GVT71256DA18 SRAMs integrate 131,072x36 and 262,144x18 SRAM cells with advanced synchronous peripheral circuitry and a 2-bit counter for internal burst operation. All synchronous inputs are gated by registers controlled by a positive-edge-triggered clock input (CLK). The synchronous inputs include all addresses, all data inputs, address-pipelining chip enable (CE#), depthexpansion chip enables (CE2# and CE2), burst control inputs (ADSC#, ADSP#, and ADV#), write enables (BWa#, BWb#, BWc#, BWd#, and BWE#), and global write (GW#).

Asynchronous inputs include the output enable (OE#) and burst mode control (MODE). The data outputs (Q), enabled by OE#, are also asynchronous.

Addresses and chip enables are registered with either address status processor (ADSP#) or address status controller (ADSC#) input pins. Subsequent burst addresses can be internally generated as controlled by the burst advance pin  (ADV#).

Address, data inputs, and write controls are registered onchip to initiate self-timed WRITE cycle. WRITE cycles can be one to four bytes wide as controlled by the write control inputs. Individual byte write allows individual byte to be written. BWa# controls DQa. BWb# controls DQb. BWc# controls DQc. BWd# controls DQd. BWa#, BWb# BWc#, and BWd# can be active only with BWE# being LOW. GW# being LOW causes all bytes to be written. The x18 version only has 18 data inputs/outputs (DQa and DQb) along with BWa# and BWb# (no BWc#, BWd#, DQc, and DQd). Four pins are used to implement JTAG test capabilities: test mode select (TMS), test data-in (TDI), test clock (TCK), and test data-out (TDO). The JTAG circuitry is used to serially shift data to and from the device. JTAG inputs use LVTTL/LVCMOS levels to shift data during this testing mode of operation.

The GVT71128DA36 and GVT71256DA18 operate from a +3.3V power supply. All inputs and outputs are LVTTL compatible