Absolute Maximum Ratings

Supply Voltage (VDD) ............................................5.5V

Storage Temperature ...........................

-50°Cto125°C

Supply Voltage (VPA) ..........................................12.5V

Operating Temperature ..............................0

°Cto70°C

Note: These are stress ratings only. Stresses exceeding the range specified under

²Absolute Maximum Ratings² may

cause substantial damage to the device. Functional operation of this device at other conditions beyond those

listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliabil-

ity.

Electrical Characteristics

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

Conditions

Operating Voltage

¾

23

4

V

Operating Current

2V

¾¾

15

¾mA

Operating Current

3V

¾¾

400

¾mA

Modulation Resistance

3.3V

¾¾

320

¾W

LC Input Limiter Voltage

¾¾

¾

6.5

¾

V

Output Data Baud Rate

3V

5

10

15

Kbps

HT672B

Rev. 1.10

3

November 23, 2004

Functional Description

Operation Concept

The reader transmits a 13.56MHz carrier signal from its

antenna, the LC tank on the transponder side converts

the carrier energy to voltage form and supply to the tran-

sponder chip with an internal pump circuit. If the induced

energy is high enough, the pumped voltage reaches the

break-in voltage of internal RC-oscillator, the tran-

sponder is actuated to transmit its internal data serially

by means of damping the LC tank.

The reader receiving the transponder

¢s data by means

of detecting the energy variation on it

¢s own antenna,

and recognize the information with a microcontroller.

The HT672B has a built-in internal Voltage Limiter to

prevent excess power supply and RF levels induced by

the LC tank from damaging the device or causing the

device to function abnormally.

A total of 40 bits of O

TP memory space is provided,

from which 20 bits wide are customer programmable,

which can be programmed using the specified program-

mer supplied by Holtek. The pre-programmed Ics are

also available upon customer

¢s request.

H T 6 7 2 B

E n e r g y

D a t a

R F o s c

&

C o n t r o l l e r

T r a n s p o n d e r

R e a d e r