M
25AA640/25LC640
64K SPI™ Bus Serial EEPROM
PACKAGE TYPES
DEVICE SELECTION TABLE
Part
Number
VCC
Range
Max Clock
Frequency
Temp
Ranges
25AA640
1.8-5.5V
1 MHz
C
25LC640
2.5-5.5V
2 MHz
25LC640
4.5-5.5V
3/2.5 MHz
PDIP/SOIC
1
C,I
SO
2
C,I/E
WP
3
VSS
4
FEATURES
VCC
7
HOLD
6
SCK
5
SI
TSSOP
HOLD
VCC
CS
SO
1
2
3
4
25xx640
• Low power CMOS technology
- Write current: 3 mA typical
- Read current: 500 µA typical
- Standby current: 500 nA typical
• 8192 x 8 bit organization
• 32 byte page
• Write cycle time: 5ms max.
• Self-timed ERASE and WRITE cycles
• Block write protection
- Protect none, 1/4, 1/2, or all of array
• Built-in write protection
- Power on/off data protection circuitry
- Write enable latch
- Write protect pin
• Sequential read
• High reliability
- Data retention: > 200 years
- ESD protection: > 4000 V
• 8-pin PDIP, SOIC, and TSSOP packages
• Temperature ranges supported:
- Commercial (C):
0°C to +70°C
- Industrial (I):
-40°C to +85°C
- Automotive (E):
-40°C to +125°C
8
25xx640
CS
8
7
6
5
SCK
SI
VSS
WP
BLOCK DIAGRAM
Status
Register
HV Generator
EEPROM
I/O Control
Logic
Memory
Control
Logic
X
Array
Dec
Page Latches
DESCRIPTION
The Microchip Technology Inc. 25AA640/25LC640
(25xx640*) is a 64K bit Serial Electrically Erasable
PROM [EEPROM]. The memory is accessed via a simple Serial Peripheral Interface (SPI) compatible serial
bus. The bus signals required are a clock input (SCK)
plus separate data in (SI) and data out (SO) lines.
Access to the device is controlled through a chip select
(CS) input.
SI
Y Decoder
SO
CS
SCK
Sense Amp.
R/W Control
HOLD
WP
VCC
VSS
Communication to the device can be paused via the
hold pin (HOLD). While the device is paused, transitions on its inputs will be ignored, with the exception of
chip select, allowing the host to service higher priority
interrupts.
*25xx640 is used in this document as a generic part number for the 25AA640/25LC640 devices.
SPI is a trademark of Motorola.
© 1999 Microchip Technology Inc.
Preliminary
DS21223D-page 1
