HCS473 Datasheet, PDF (57/68 Pages) Microchip Technology – Code Hopping Encoder and Transponder

HCS473
Analog delays
TFILTR
—
15 µs
—
HCS473 analog LF filter charge time
TFILTF
—
70 µs
—
HCS473 analog LF filter discharge time
TANTR
Hardware design dependent
Cumulative LF antenna delay when field is turned on
TANTF
Hardware design dependent
Cumulative LF antenna delay when field is turned off
Note 1: Fosc = 4 MHz. FOSC = 4 MHz may be centered at the designer’s choice of supply voltage (VDD) and tempera-
ture.
2: LFTE is based on the HCS473’s timing, not the timing of the transponder reader. Therefore LFTE is subject to
HCS473 oscillator variation.
3: Response timing accounts for TFILTR but not for TANTR or TANTF, as they are design dependent. The system
designer must compensate communication accordingly for TANTR and TANTF.
4: Min and Max values modified for FOSC = 4 MHz + 10%, -20%. Timing parameters are characterized but not
tested. Very Important: Refer to Section 3.2.7 for communication requirements when using an Industrial tem-
perature device at 3.5V < VDD < 5.5V.
 2002 Microchip Technology Inc.
Preliminary
DS40035C-page 55