HT6720

13.56MHz RFID Transponder

Block Diagram

Rev. 1.00

1

August 13, 2001

Features

Applications

General Description

The HT6720 is an RF transponder IC with 13.56MHz RF

carrier, which provides a low cost batteryless tran-

sponder solution when combined with an external in-

ductor. The inductor and internal capacitor form an LC

tank which induce voltage from the radiated 13.56MHz

carrier signal generated from the reader antenna.

HT6720 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 re-

sponse signal (pre-programmed in the OTP memory) is

serially transmitted out. The response data is transmit-

ted using PWM/ASK modulation. Modulation of

13.56MHz is accomplished by damping the LC tank with

a fixed baud rate.

The transmission information is stored in a 96 bits one

time programmable memory OTP, with a 16-bit CRC

code (up to 64 bits reserved for customer). The effective

detection range for a small sized antenna is 2cm~10cm

which is dependent on antenna format & reader design.

The larger the antenna loop used the longer the detec-

tion range. It is advisable to use larger antenna to attain

a 15 cm detection range.

Implementing Holtek¢s advanced OTP and low power

technology, HT6720 offers a very cost effective solution

for RF contactless detection system.

A code area of 64-bits (max.) wide is provided so cus-

tomers can program the device using the specified pro-

grammer supplied by Holtek. The pre-programmed ICs

are also available upon customer¢s request.

VP A

CL K

HF 2

HF 1

VD D

VS S

PW M / AS K

M odul at or

Sh i f t

R egi s t er

Da t a

EP R O M

Sys t e m

Cl o c k

G ene r a t o r

VC C L i m i t e r

and

RF L i m i t e r

Da t a

P r oc es s i ng

Po w e r O N

Re s e t

T e s t and

EP R O M

P r ogr am m i ng

C ont r o l