Replacing MB85RS128/FM25V01 with GX25C128 FRAM in CPAP Applications

CPAP is a mainstream home medical device for treating obstructive sleep apnea. During continuous overnight operation, the device continuously records the user‘s respiratory events, pressure fluctuations, and usage duration, and ensures that the current therapy settings and log data are not lost in the event of a sudden power failure. The memory in this application solution needs to feature high write endurance and immediate write capability. This article mainly introduces the application of GX25C128 in CPAP.

Traditional memories such as EEPROM and Flash suffer from slow write speed and low endurance, and both have limitations in frequent-write scenarios. GX25C128 adopts ferroelectric process and silicon-gate CMOS process technologies, combining RAM-level write speed with near-infinite read/write endurance, providing a solution to the above contradiction.

In CPAP use, the pressure curves and apnea event index data that need to be recorded are written at extremely high frequencies. The memory cell of GX25C128 supports 1E11 read/write operations, operates at a frequency of up to 25MHz, and supports a 40MHz high-speed read command. GX25C128 also offers excellent data retention capability, maintaining reliable data retention of 10 years @85°C (200 years @25°C) within the industrial temperature range. This means that even if the device performs thousands of log writes per day, the chip‘s lifespan can still cover the entire product lifecycle. Key parameters:

• Capacity: 2M

• Interface type: SPI interface (Mode 0 and Mode 3)

• Operating voltage: 2.7V to 3.6V

• Operating frequency: 25MHz

• Power consumption: 4.5mA, 1uA (standby)

• Data retention: 10 years @85°C (200 years @25°C)

• High-speed read feature: supports 40MHz high-speed read command

• Operating ambient temperature range: -40°C to 85°C

• Package options: SOP8 150mil package, SOP8 208mil package, RoHS compliant

• PIN TO PIN replacement for MB85RS2M/FM25V20