M
25AA640/25LC640/25C640
64K SPI
™
Bus Serial EEPROM
PACKAGE TYPES
Temp
Ranges
C,I
C,I
C,I,E
CS
SO
WP
V
SS
PDIP/SOIC
1
25xx640
2
3
4
8
7
6
5
V
CC
HOLD
SCK
SI
Max Clock
Frequency
1 MHz
2 MHz
3 MHz
DEVICE SELECTION TABLE
Part
Number
25AA640
25LC640
25C640
V
CC
Range
1.8-5.5V
2.5-5.5V
4.5-5.5V
FEATURES
• Low power CMOS technology
- Write current: 3 mA typical
- Read current: 500
µ
A 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
- Endurance: 1M cycles (guaranteed)
- 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) (25C640)
-40
°
C to +125
°
C
TSSOP
HOLD
V
CC
CS
SO
1
2
3
4
8
7
6
5
SCK
SI
V
SS
WP
25xx640
BLOCK DIAGRAM
Status
Register
HV Generator
EEPROM
I/O Control
Logic
Memory
Control
Logic
X
Dec
Page Latches
Array
DESCRIPTION
The Microchip Technology Inc. 25AA640/25LC640/
25C640 (25xx640
*
) is a 64K bit serial Electrically Eras-
able PROM. 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.
Communication to the device can be paused via the
hold pin (HOLD). While the device is paused, transi-
tions on its inputs will be ignored, with the exception of
chip select, allowing the host to service higher priority
interrupts.
SI
SO
CS
SCK
HOLD
WP
V
CC
V
SS
Sense Amp.
R/W Control
Y Decoder
*25xx640 is used in this document as a generic part number for the 25AA640/25LC640/25C640 devices.
SPI is a trademark of Motorola.
©
1997 Microchip Technology Inc.
Preliminary
DS21223A-page 1
MICROCHIP [ MICROCHIP TECHNOLOGY ]
