Application Note
2 of 19
001-87564 Rev.*D
2021-06-01
A Design Guide to SPI F-
RAM™ Processor Companion
- FM33256B
Introduction
r e s t r i c t e d
1
Introduction
The FM33256B is a 256-Kbit serial (SPI) F-RAM memory product, which offers an integrated processor
companion and an RTC. The processor companion section includes a power-on system reset, low-voltage
detect, a watchdog timer, an early power-fail warning, an event counter, automatic switchover to backup
power, and a lockable 64-bit serial number. It employs an industry-standard SPI, which is used to access the
memory, the processor companion, and the RTC. The FM33256B operates over a 2.7 V-to-3.6 V power supply
range with the maximum SPI frequency of 16 MHz. It is available in an SOIC-14 package.
