FM21L16 - 128Kx16 FRAM

Rev. 2.0

Apr. 2011

Page 2 of 15

CE

Control

Logic

WE

A(16:2)

A(1:0)

I/O Latch & Bus Driver

OE

DQ(15:0)

16K x 16 block

16K x 16 block

16K x 16 block

16K x 16 block

16K x 16 block

16K x 16 block

16K x 16 block

16K x 16 block

A(16:0)

Column Decoder

UB, LB

2

ZZ

Figure 1. Block Diagram

Pin Description

Pin Name

Type

Pin Description

A(16:0)

Input

Address inputs: The 17 address lines select one of 131,072 words in the F-RAM array. The

lowest two address lines A(1:0) may be used for page mode read and write operations.

/CE

Input

Chip Enable input: The device is selected and a new memory access begins when /CE is low

and /ZZ is high. The entire address is latched internally on the falling edge of /CE. Subsequent

changes to the A(1:0) address inputs allow page mode operation when /CE is low.

/WE

Input

Write Enable: A write cycle begins when /WE is asserted. The rising edge causes the

FM21L16 to write the data on the DQ bus to the F-RAM array. The falling edge of /WE

latches a new column address for page mode write cycles.

/OE

Input

Output Enable: When /OE is low, the FM21L16 drives the data bus when valid read data is

available. Deasserting /OE high tri-states the DQ pins.

/ZZ

Input

Sleep: When /ZZ is low, the device enters a low power sleep mode for the lowest supply

current condition. Since this input is logically AND’d with /CE, /ZZ must be high for normal

DQ(15:0)

I/O

Data: 16-bit bi-directional data bus for accessing the F-RAM array.

/UB

Input

Upper Byte Select: Enables DQ(15:8) pins during reads and writes. These pins are hi-Z if /UB

is high. If the user does not perform byte writes and the device is not configured as a 256Kx8,

the /UB and /LB pins may be tied to ground.

/LB

Input

Lower Byte Select: Enables DQ(7:0) pins during reads and writes. These pins are hi-Z if /LB

is high. If the user does not perform byte writes and the device is not configured as a 256Kx8,

the /UB and /LB pins may be tied to ground.

VDD

Supply

Supply Voltage

VSS

Supply

Ground