RFHCS362G_11 Datasheet, PDF (10/54 Pages) Microchip Technology – KEELOQ® Code Hopping Encoder with UHF ASK/FSK Transmitter

rfHCS362G/362F
FIGURE 2-2: I/O CIRCUITS
S0, S1, S2, RFENIN
Inputs
RS
S3 Input/
RFEN Output
VDD
PFET
RS
RFEN
VDD
PFET
NFET
DATA
DATA I/O
RDATA
LED output
SHIFT input
SHIFT
RL
RH
LEDL
NFET
NFET
LEDH
FSKOUT OUTPUT
ANT1, ANT2 outputs
NFET
RFENIN input
VDDRF
XTAL
V
Change
LF
200Ω
Pump
DATAFSK input
200Ω
VCO
5 pF
VDDRF
CLKOUT
output
PFET
NFET
VDDRF
V ^{20 μA}
PS/DATAASK
PS
PLL Lock
2.1 Encoder Architectural Overview
2.1.1 ONBOARD EEPROM
The rfHCS362G/362F has an onboard nonvolatile
EEPROM which is used to store user programmable
data. The data can be programmed at the time of pro-
duction and includes the security-related information
such as encoder keys, serial numbers, discrimination
and seed values. All the security related options
are read protected. The rfHCS362G/362F has built-in
protection against counter corruption. Before every
EEPROM write, the internal circuitry also ensures that
the high voltage required to write to the EEPROM is at
an acceptable level.
2.1.2 INTERNAL RC OSCILLATOR
The rfHCS362G/362F has an onboard RC oscillator
that controls all the logic output timing characteristics.
The oscillator frequency varies within ±10% of the
nominal value (once calibrated over a voltage range of
2V – 3.5V or 3.5V – 6.3V). All the timing values
specified in this document are subject to the oscillator
variation.
FIGURE 2-3: TYPICAL rfHCS362G/362F
NORMALIZED OSCILLATOR
PERIOD VS. TEMPERATURE
1.10
1.08
1.06
1.04
1.02
1.00
0.98
0.96
0.94
0.92
0.90
-50-40-30-20-10 0 10 20 30 40 50 6070 80 90
Temperature °C
VDD Legend
= 2.0V
= 3.0V
= 6.0V
Note: Values are for calibrated oscillator
DS41189B-page 10
© 2011 Microchip Technology Inc.