11/12/2003 - Atmel® Corporation (Nasdaq: ATML) announced the availability of the new LF ASK 125 kHz ultra low power receiver IC ATA5282 with three input channels for 3-dimensional (3-D) antennas. This device is the first remote control receiver IC available on the market that has a digital 8-bit RSSI output for improved location preciseness. The ATA5282 is designed for Passive Entry Go (PEG) systems in automotive and access control applications. By adding up to three antenna coils, a microcontroller, an RF transmitter or transceiver (such as Atmel's T575x, T5743, T5760, ATA5811/12 family) and a battery, a complete, hands-free key fob for PEG systems can be designed.
The ATA5282 is the first 3-dimensional LF receiver IC with digital 8-bit RSSI, whereas competing solutions provide analog RSSI outputs, where the microcontroller needs an additional A/D converter for signal decoding. In PEG systems, the RSSI function (measurement of the magnetic field strength) is important for the precise definition of the card's location. A PEG system recognizes by comparing the magnetic field strengths of the various trigger systems if the card is inside or outside of the car. If the card is not recognized to be within the car, the motor will not start. This helps to prevent unintended car start as caused, for example, by playing children. The 8-bit RSSI output, as well as the 3 inputs for 3-dimensional measurement, increase the position preciseness and thus the system safety.
The receiver's 3 active input stages provide maximum wake-up sensitivity of typically better than 3 mVPP.These stages measure and demodulate the input signal from the antenna coil, taking advantage of the distribution behavior of the magnetic field strength. Therefore, the IC serves as a sensor input for waking up the microcontroller which in turn controls the RF transmitter and sends the data signal including the RSSI values.
A preamble must be detected to activate the internal oscillator. The following specific header in OOK mode with 50% duty cycle and 8 consecutive samples of rising and falling edges need to be detected before the data pin switches in active stage. The demodulated and merged signal of the 3 input stages is then provided via the data output pin. If no valid header has been detected within 2 milliseconds, beginning at the end of the preamble, the header time-out check stops the oscillator and resets the gain control as well as the header detection circuit to their initial state.
The current consumption, which is an important parameter for small, battery-driven applications such as a car key, is as low as 2 microampere in standby and 4 microampere in active mode.
The device allows typical data receiving distances of up to 2.5 m from the external trigger base stations, depending on the corresponding magnetic field strength. The ATA5282's operation voltage is 2 to 4.2 V within an operation temperature range of -40 to +85 degrees C.
Samples of the transceivers ATA5282 in extra small TSSOP8 packages are available now. Pricing starts at 1.05 US$ (10 k).
3-D = 3-dimensional
A/D converter = Analog/ Digital converter
ASK = Amplitude Shift Keying
LF = Low Frequency
OOK = On-Off Keying
PEG = Passive Entry Go
RKE = Remote Keyless Entry
RSSI = Receive Signal Strength Indicator
Founded in 1984, Atmel Corporation is headquartered in San Jose, California with manufacturing facilities in North America and Europe. Atmel designs, manufactures and markets worldwide, advanced logic, mixed-signal, nonvolatile memory and RF semiconductors. Atmel is also a leading provider of system-level integration semiconductor solutions using CMOS, BiCMOS, SiGe, and high-voltage BCDMOS process technologies.
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Atmel's transceiver ATA5282 information may be retrieved at: http://www.atmel.com/dyn/products/product_card.asp?part_id=3147
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