1
Features
• Single 4.5V - 5.5V Supply
• Serial Interface Architecture
• Page Program Operation
– Single Cycle Reprogram (Erase and Program)
– 1024 Pages (264 Bytes/Page) Main Memory
• Two 264-Byte SRAM Data Buffers – Allows Receiving of Data
while Reprogramming of Nonvolatile Memory
• Internal Program and Control Timer
• Fast Page Program Time – 7 ms Typical
• 80 µs Typical Page to Buffer Transfer Time
• Low Power Dissipation
– 15 mA Active Read Current Typical
–15 µA CMOS Standby Current Typical
• 10 MHz Max Clock Frequency
• Hardware Data Protection Feature
• Serial Peripheral Interface (SPI) Compatible – Modes 0 and 3
• CMOS and TTL Compatible Inputs and Outputs
• Commercial and Industrial Temperature Ranges
Description
The AT45D021 is a 5-volt only, serial interface Flash memory suitable for in-system
reprogramming. Its 2,162,688 bits of memory are organized as 1024 pages of 264-
bytes each. In addition to the main memory, the AT45D021 also contains two data
SRAM buffers of 264-bytes each. The buffers allow receiving of data while a page in
the main memory is being reprogrammed. Unlike conventional Flash memories that
are accessed randomly with multiple address lines and a parallel interface, the
DataFlash uses a serial interface to sequentially access its data. The simple serial
interface facilitates hardware layout, increases system reliability, minimizes switching
2-Megabit
5-volt Only
Serial
DataFlash
®
AT45D021
Rev. 0869B–07/98
Pin Configurations
Pin Name Function
CS Chip Select
SCK Serial Clock
SI Serial Input
SO Serial Output
WP Harware Page Write
Protect Pin
RESET Chip Reset
RDY/BUSY Ready/Busy
PLCC
Note: PLCC package pins 16 and 17
are DON’T CONNECT.
5
6
7
8
9
10
11
12
13
29
28
27
26
25
24
23
22
21
SCK
SI
SO
NC
NC
NC
NC
NC
NC
WP
RESET
RDY/BUSY
NC
NC
NC
NC
NC
NC
4 3 2 1
32 31 30
14 15 16 17 18 19 20
NC NC DC DC NC NC NC
CS NC NC GND VCC NC NC
TSOP Top View
Ty pe 1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
RDY/BUSY
RESET
WP
NC
NC
VCC
GND
NC
NC
NC
CS
SCK
SI
SO
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
PLCC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
GND
NC
NC
CS
SCK
SI
SO
NC
NC
NC
NC
NC
NC
NC
VCC
NC
NC
WP
RESET
RDY/BUSY
NC
NC
NC
NC
NC
NC
NC
NC
(continued)