Replacing MB85RS128/FM25V01 with GXSC GX25C128 in Heat Meters

A heat meter/thermal energy meter is a measuring instrument that measures and displays the heat released or absorbed by water flowing through a heat exchange system. It is a mechatronic instrument based on a microprocessor and high-accuracy sensors. It usually consists of three parts: a flow sensor, a paired temperature sensor, and an integrator. By measuring the fluid flow rate and the temperature difference between inlet and outlet, and combining these with the enthalpy value, it calculates the heat value.

Heat meters are usually battery-powered, with a design life requirement of 6 to 10 years. This means that the average power consumption of the entire system must be controlled at the microampere level. However, heat data needs to be continuously accumulated and updated. Flow pulses, temperature sampling, and accumulated heat values all need to generate new data in real time. If these data need to be persistently stored, the write power consumption and write frequency of the memory become key variables in the system power budget.

The GXSC ferroelectric memory GX25C128 uses a ferroelectric memory process and features delay-free real-time writing and ultra-high read/write endurance of one million cycles. Compared with traditional memory devices, it completely eliminates write wait delays and the erase/write endurance bottleneck, enabling high-frequency, zero-loss data storage. It is suitable for scenarios such as high-frequency parameter logging, power-down parameter saving, and fault log storage.

In instrument and meter design, heat meters are installed in heating pipe wells, where the environment is harsh and occasional power interruptions are not uncommon. If accumulated heat data is lost at the moment of power failure, it not only means billing disputes, but may also trigger a rollback of the entire meter‘s data, seriously affecting metering standards. The SF25C128 has excellent data retention capability and can maintain reliable data retention for 10 years @85℃ (200 years @25℃) within the industrial temperature range.

Introduction to the main parameters of the GX25C128:

• Capacity: 128Kb

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

• Operating voltage: 2.7V to 3.6V

• Operating frequency: 25MHz

• Power consumption: 4.2 mA, 9 uA (standby)

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

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

• Operating ambient temperature range: -40℃ to 85℃

• Package type: 8-pin SOP package, RoHS compliant

• Replaces MB85RS128 and FM25V01