Rainbow Electronics ATA6286 - Manual (Page 10)

10
4958AS–AUTO–09/06
ATA6285/ATA6286 [Preliminary]
4. UHF ASK/FSK Transmitter for ATA6285/ATA6286
4.1 Features
• PLL Transmitter IC with Single-ended Output
• High output Power (6 dBm) at 8.1 mA (315 MHz) and 8.5 mA (433 MHz) Typical Values
• Divide by 24 (ATA6285) and 32 (ATA6286) Blocks for 13 MHz Crystal Frequencies and for Low XTO
Start-up Times
• Modulation Scheme ASK/FSK with Internal FSK Switch
• Up to 20 Kbits/s Manchester Coding, Up to 40 Kbits/s NRZ Coding
• Power-down Idle and Power-up Modes to Adjust Corresponding Current Consumption through
ASK/FSK/Enable Input Pins
• ENABLE Input for Parallel Usage of Controlling Pins in a 3-wire Bus System
• CLK Output Switches ON if the Crystal Current Amplitude Has Reached 35% to 80% of its Final
Value
• Crystal Oscillator Time until CLK Output Is Activated, Typically 0.6 ms
4.2 Benefits
• Low Parasitic FSK Switch Integrated
• Very Short and Reproducible Time to Transmit Typically < 0.85 ms
• 13.125 MHz/13.56 MHz Crystals Give Opportunity for Small Package Sizes
4.3 Description
The ATA6285/ATA6286 is a PLL transmitter part which has been developed for the demands of
RF low-cost transmission systems at data rates up to 20 Kbits/s Manchester coding and
40 Kbits/s NRZ coding. The transmitting frequency range is 313 MHz to 317 MHz (ATA6285)
and 432 MHz to 448 MHz (ATA6286), respectively. It can be used in both FSK and ASK sys-
tems. Due to its shorten crystal oscillator settling time it is well suited for Tire Pressure
Monitoring (TPMS) and for Passive Entry Go applications.
Figure 4-1. System Block Diagram
Power
amp.
(LNA, Mixer,
VCO, PLL,
IF Filter,
RSSI Amp.,
Demodulator)
Micro-
controller
Interface
Micro-
controller
Digital
Control
Logic
Power
Supply
RF Receiver
PLL
UHF ASK/FSK Receiver UHF ASK/FSK TPM
Transmitter Part of
ATA6285/ATA6286
VCO
XTO
Antenna
4 to 8
Encoder
ATARx9x
VCO
1 Li cell
Keys
Antenna