In meeting with industrial specifications requirements of -40°C ~ 85°C operating temperature and with their high noise immunity characteristics, these devices also include an abundant set of system resources. Features include 2K, 4K or 8K Words of flash program memory and a range of peripheral functions such as a 12-bit A/D converter, 8-bit D/A converter, comparator, OPAs, multi-function Timer Modules, I2C/SPI and UART interfaces.

The HT66F4550 device provides an additional 16-bit D/A Converter which can implement voice functions. The integrated OPAs can be used to amplify small environmental analog signals which with their 4-level bandwidth selection function, enables users to adjust the bandwidth according to their required response times to effectively further reduce power consumption. With regard to packaging, the HT66F4530 is supplied in 16-pin NSOP and 20-pin SSOP package types while the HT66F4540/4550 are supplied in 24/28-pin SSOP package types.

Holtek also supplies a full suite of excellent hardware and software development tools. The Holtek e-Link together with the HT-IDE3000 software development tools, provides a complete development system with which users can implement debugging directly on the application board. The Holtek e-WriterPro also provides a means of In-Circuit Programming to enable users to develop and update their programs conveniently and easily.