25LC640-I/P Microchip Technology, 25LC640-I/P Datasheet - Page 9

• Manufacturer Part Number: 25LC640-I/P
• Description: IC EEPROM 64KBIT 2MHZ 8DIP
• Manufacturer: Microchip Technology

Specifications of 25LC640-I/P

• Memory Size: 64K (8K x 8)
• Package / Case: 8-DIP (0.300", 7.62mm)
• Operating Temperature: -40°C ~ 85°C
• Format - Memory: EEPROMs - Serial
• Memory Type: EEPROM
• Speed: 2MHz
• Interface: SPI, 3-Wire Serial
• Voltage - Supply: 2.5 V ~ 5.5 V
• Organization: 8 K x 8
• Interface Type: SPI
• Maximum Clock Frequency: 2 MHz
• Access Time: 230 ns
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.5 V
• Maximum Operating Current: 5 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Operating Supply Voltage: 2.5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

3.4
The 25XX640 contains a write enable latch. See
Table 3-3 for the Write-Protect Functionality Matrix.
This latch must be set before any write operation will be
completed internally. The WREN instruction will set the
latch, and the WRDI will reset the latch.
FIGURE 3-4:
FIGURE 3-5:
© 2008 Microchip Technology Inc.
Write Enable (WREN) and
Write Disable (WRDI)
WRITE ENABLE SEQUENCE
WRITE DISABLE SEQUENCE
SCK
SCK
CS
CS
SO
SO
SI
SI
0
0
0
0
0
0
1
1
High-Impedance
High-Impedance
0
0
2
2
0
0
3
3
The following is a list of conditions under which the
write enable latch will be reset:
• Power-up
• WRDI instruction successfully executed
• WRSR instruction successfully executed
• WRITE instruction successfully executed
0
0
4
4
25AA640/25LC640
1
1
5
5
1
1 0
6
6
0
0
7
7
DS21223H-page 9