MR25H40MDF Everspin Technologies, MR25H40MDF Datasheet - Page 8

• Manufacturer Part Number: MR25H40MDF
• Description: NVRAM 4Mb 3.3V 512Kx8 SPI Pre-Qual Sample MRAM
• Manufacturer: Everspin Technologies

Specifications of MR25H40MDF

• Rohs: yes
• Data Bus Width: 8 bit
• Memory Size: 4 MB
• Organization: 512 K x 8
• Interface Type: SPI
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 3 V
• Operating Current: 20 mA
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Package / Case: DFN-8
• Maximum Power Dissipation: 0.6 W
• Operating Temperature Range: - 40 C to + 125 C
• Operating Voltage: 3 V to 3.6 V

Write Data Bytes (WRITE)
The Write Data Bytes (WRITE) command allows data bytes to be written starting at an address specified by
the 24-bit address. Only address bits 0-18 are decoded by the memory. The data bytes are written sequen-
tially in memory until the write operation is terminated by bringing CS high. The entire memory can be
written in a single command. The address counter will roll over to 0000h when the address reaches the top
of memory.
Unlike EEPROM or Flash Memory, MRAM can write data bytes continuously at its maximum rated clock
speed without write delays or data polling. Back to back WRITE commands to any random location in mem-
ory can be executed without write delay. MRAM is a random access memory rather than a page, sector, or
block organized memory so it is ideal for both program and data storage.
The WRITE command is entered by driving CS low, sending the command code, and then sequential write
data bytes. Writes continue as long as the memory is clocked. The command is terminated by bringing CS
high.
Everspin Technologies © 2011
SPI COMMUNICATIONS PROTOCOL
SCK
SCK
CS
CS
SO
SO
SI
SI
7
0
40
0
6
41
0
1
5
42
0
2
Instruction (02h)
MSB
Data Byte 2
4
43
0
3
3
44
0
4
2
45
0
5
High Impedance
1
46
High Impedance
1
6
0
47
0
7
7
48
MSB
23
8
Figure 2.6 WRITE
6
49
22
9
5
50
21
Data Byte 3
10
4
24-Bit Address
51
8
3
52
3
28
2
53
2
29
1
54
1
0
30
55
0
31
MSB
MSB
7
7
32
6
6
33
5
5
34
MR25H40 Rev. 5, 11/2011
Data Byte N
4
4
35
MR25H40
3
3
36
2
2
37
1
1
38
0
0
39
Mode 3
Mode 0