In FRAM devices, digital information is stored as polarization in a dielectric. This polarization can be lost at a

temperature-dependent rate. Increasing temperatures increase the de-polarization rate. Data Retention metrics

are listed in the Electrical Characteristics table.

6.3.2 FRAM Status Memory

As shown in Table 6-1, the data memory of the TMF0008 consists of eight contiguous blocks of FRAM memory.

Blocks 0 to 6 are 128 bytes each, formed by four adjacent memory pages, whereas block 7 is 64 bytes, formed

by two adjacent memory pages (A data memory page is 32 adjacent memory bytes).

In addition to the data memory, the TMF0008 consists of the status memory starting at address 03C0h as shown

in Table 6-2. The register page in the status memory consists of eight protection control bytes, six bytes of user

EEPROM, and one byte each to lock the memory block and the register page.

The eight protection control bytes and the memory block lock byte together control the access to the eight data

memory blocks. By default, the memory blocks are set to open access. A protection byte value of 55h sets

the corresponding memory block to write protection mode, whereas a protection byte value of AAh sets the

corresponding memory block to EPROM mode.

If the memory block lock byte is programmed to either 55h or AAh, copy protection is set for all write-protected

data memory blocks (memory blocks in EPROM mode are not affected). Similarly, if the register page lock byte

is programmed to either 55h or AAh, copy protection is set for the entire register page.

Setting a memory location into write protection mode allows the copy-scratch pad operation, but prevents data

from being changed. This allows memory to be reprogrammed with the same data, refreshing the polarization for

data retention longevity.

As compared to write protection, copy protection blocks the copy-scratchpad function. Only use this feature

after all write-protected blocks and associated protection control bytes are set to the final values. Note that

copy protection does not prevent copying data across devices. When set to 55h or AAh, the protection control

registers and the lock bytes write-protect themselves. Any other setting allows unrestricted write access.

Addresses 03D1h and 03D2h are available for programming an optional manufacturer ID. These values can

be read by the host, for example, to associate an end-user product with a TMF0008. At address 03D0h, the

TMF0008 stores a byte for locking the manufacturer ID, with a default value of 00h. After writing AAh or 55h to

this location, the manufacturer ID and lock byte are permanently write protected.

Table 6-2. FRAM Status Memory Map

ADDRESS RANGE

TYPE (1)

DESCRIPTION

PROTECTION CODES (NOTES)

03C0h

R/(W)

Protection Control Byte (Block 0)

55h: Write Protect Block 0;

AAh: EPROM Mode Block 0;

55h or AAh: Write Protect 03C0h

03C1h

R/(W)

Protection Control Byte (Block 1)

55h: Write Protect Block 1;

AAh: EPROM Mode Block 1;

55h or AAh: Write Protect 03C1h

03C2h

R/(W)

Protection Control Byte (Block 2)

55h: Write Protect Block 2;

AAh: EPROM Mode Block 2;

55h or AAh: Write Protect 03C2h

03C3h

R/(W)

Protection Control Byte (Block 3)

55h: Write Protect Block 3;

AAh: EPROM Mode Block 3;

55h or AAh: Write Protect 03C3h

03C4h

R/(W)

Protection Control Byte (Block 4)

55h: Write Protect Block 4;

AAh: EPROM Mode Block 4;

55h or AAh: Write Protect 03C4h

03C5h

R/(W)

Protection Control Byte (Block 5)

55h: Write Protect Block 5;

AAh: EPROM Mode Block 5;

55h or AAh: Write Protect 03C5h

03C6h

R/(W)

Protection Control Byte (Block 6)

55h: Write Protect Block 6;

AAh: EPROM Mode Block 6;

55h or AAh: Write Protect 03C6h

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TMF0008

SLVSIV3 – JULY 2025

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