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IDT71V3556, IDT71V3558, 128K x 36, 256K x 18, 3.3V Synchronous SRAMS with

ZBT

™

™

™

™

™ Feature, 3.3V I/O, Burst Counter, and Pipelined Outputs

Commercial and Industrial Temperature Ranges

NOTE:

1. All synchronous inputs must meet specified setup and hold times with respect to CLK.

Symbol

Pin Function

I/O

Active

Description

Address Inputs

I

N/A

Synchronous Address inputs. The address register is triggered by a combination of the rising edge of CLK,

ADV/LD low, CEN low, and true chip enables.

ADV/LD

Advance / Load

I

N/A

ADV/LD is a synchronous input that is used to load the internal registers with new address and control when it

is sampled low at the rising edge of clock with the chip selected. When ADV/LD is low with the chip

deselected, any burst in progress is terminated. When ADV/LD is sampled high then the internal burst counter

is advanced for any burst that was in progress. The external addresses are ignored when ADV/ LD is sampled

high.

R/W

Read / Write

I

N/A

R/W signal is a synchronous input that identifies whether the current load cycle initiated is a Read or Write

access to the memory array. The data bus activity for the current cycle takes place two clock cycles later.

CEN

Clock Enable

I

LOW

Synchronous Clock Enable Input. When CEN is sampled high, all other synchronous inputs, including clock are

ignored and outputs remain unchanged. The effect of CEN sampled high on the device outputs is as if the low

to high clock transition did not occur. For normal operation, CEN must be sampled low at rising edge of clock.

Individual Byte

Write Enables

ILOW

Synchronous byte write enables. Each 9-bit byte has its own active low byte write enable. On load write cycles

write signal must also be valid on each cycle of a burst write. Byte Write signals are ignored when R/W is

tied low if always doing write to the entire 36-bit word.

Chip Enables

I

LOW

Chip Enable

I

HIGH

CLK

Clock

I

N/A

This is the clock input to the IDT71V3556/58. Except for OE, all timing references for the device are made with

respect to the rising edge of CLK.

Data Input/Output

I/O

N/A

Synchronous data input/output (I/O) pins. Both the data input path and data output path are registered and

triggered by the rising edge of CLK.

LBO

Linear Burst Order

I

LOW

Burst order selection input. When LBO is high the Interleaved burst sequence is selected. When LBO is low

the Linear burst sequence is selected. LBO is a static input and it must not change during device operation.

OE

Output Enable

I

LOW

Asynchronous output enable. OE must be low to read data from the 71V3556/58. When OE is high the I/O pins

are in a high-impedance state. OE does not need to be actively controlled for read and write cycles. In normal

operation, OE can be tied low.

TMS

Test Mode Select

I

N/A

Gives input command for TAP controller. Sampled on rising edge of TDK. This pin has an internal pullup.

TDI

Test Data Input

I

N/A

Serial input of registers placed between TDI and TDO. Sampled on rising edge of TCK. This pin has an internal

pullup.

TCK

Test Clock

I

N/A

Clock input of TAP controller. Each TAP event is clocked. Test inputs are captured on rising edge of TCK,

while test outputs are driven from the falling edge of TCK. This pin has an internal pullup.

TDO

Test Data Output

O

N/A

Serial output of registers placed between TDI and TDO. This output is active depending on the state of the TAP

controller.

TRST

JTAG Reset

(Optional)

ILOW

Optional Asynchronous JTAG reset. Can be used to reset the TAP co ntroller, but not required. JTAG reset

occurs automatically at power up and also resets using TMS and TCK per IEEE 1149.1. If not used TRST can

be left floating. This pin has an internal pullup. Only available in BGA package.

ZZ

Sleep Mode

I

HIGH

Synchronous sleep mode inp ut. ZZ HIGH will gate the CLK internally and power down the IDT71V3556/3558 to

its lowest power consumption level. Data retention is guaranteed in Sleep Mode. This pin has an internal

pulldown.

Power Supply

N/A

N/A

3.3V core power supply.

Power Supply

N/A

N/A

3.3V I/O Supply.

Ground

N/A

N/A

Ground.

5281 tbl 02

The IDT71V3556/58 has an on-chip burst counter. In the burst

mode, the IDT71V3556/58 can provide four cycles of data for a single

address presented to the SRAM. The order of the burst sequence is

defined by the LBO input pin. The LBO pin selects between linear and

interleaved burst sequence. The ADV/LD signal is used to load a new

external address (ADV/LD = LOW) or increment the internal burst

counter (ADV/LD = HIGH).

The IDT71V3556/58 SRAMs utilize IDT's latest high-performance

CMOS process and are packaged in a JEDEC standard 14mm x

20mm 100-pin thin plastic quad flatpack (TQFP) as well as a 119 ball

grid array (BGA) and a 165 fine pitch ball grid array (fBGA).

Description continued