Holtek rolls out another RF transponder IC

The new RF transponder IC from Holtek Semiconductor operates with 13.56MHz RF carrier, providing a low cost battery-less transponder solution with the addition of merely an external inductor.

The inductor and internal capacitor form an LC tank that induces voltage from the radiated 13.56MHz carrier signal generated from the reader antenna.

The new HT672B has a built-in low power RC oscillator which is activated if the induced carrier field strength is high enough to supply the operating current and the response signal (pre-programmed in the OTP memory) is serial transmitted out. The response data is transmitted using PWM/ASK modulation, and the modulation of 13.56MHz is accomplished by damping the LC tank with a fixed baud rate.

In addition, the transmission information is stored in 40bits. A One Time Programmable (OTP) memory (up to 32 bits reserved for the customer) is included in the chip with an 8bit checksum code (up to 32 bits reserved for the customer).

The effective detection range for a small sized antenna is between 2cm and 10cm, depending on antenna format and reader design, Holtek said. The larger the antenna loop used, the longer the detection range. It is advisable to use larger antenna to attain a 15cm detection range, the company added.

Implementing Holtek's advanced OTP and low power technology, the HT672B offers a cost effective solution for RF contactless detection system. A code area of 32bits (max.) wide is provided so customers can program the device using the specified programmer supplied by the company. The pre-programmed ICs are also available upon customer's request.

Offered in an 8-pin DIP package, the device comes with a wide operating voltage range.