The HT45FH23A has a 2K×15 Flash Program Memory, a 128-byte Data Memory while the HT45FH24A has a 4K×16 Flash Program Memory and a 192-byte Data Memory. Both devices have a 64-byte true Data EEPROM and 6-level subroutine nesting.

The devices also have a range of practical peripheral functions such as 10-bit and16-bit timer modules, a multi-channel 12-bit A/D converter, a low power consumption high speed internal RC oscillator, two OPAs and so on. The fully integrated highly accurate internal high speed RC oscillator can provide a fixed system frequency of 910kHz with a current consumption of only 110µA at a power supply voltage of 3.3V.

In addition, the devices include a 3.3V LDO with a high maximum input voltage of 42V, a two line type power line data transceiver and a constant current modulator communication circuit, thus reducing greatly the required number of external components and PCB area. The devices are supplied in a 20-pin SOP package type making them applicable for use in different fire protection product applications.