Atmel : RF transmitter boosts flexibility for car access and TPMS applications

Atmel Corp. has announced the fully integrated fractional-N PLL RF transmitter IC ATA5749 for car access and TPMS applications. The new device is one of the very few automotive RF transmitter ICs that is fully programmable, thus enabling flexible system design and adaptation. Moreover, it is one of only a few such devices with ultra low power consumption – a significant factor for TPMS applications. For both RKE and TPMS applications, a single crystal type and a single board design (with only minor modifications) can be used for the standard 315 MHz and 433 MHz frequency ranges.

The IC's single-ended antenna output power can be adjusted in the range of -0.5 dBm to 12.5 dBm via an SPI bus interface. In each mode, the lowest possible current consumption for a given output power can be selected. For example, when used in a TPMS module, the active current consumption in transmission mode at an output power of 5.5 dBm is 7.3 mA (typical) and 8.8 mA (maximum). This is about 20% less than the values of currently available solutions on the market. Lower current consumption, of course, results in a longer battery lifetime, a critical factor for TPMS applications. Furthermore, in extreme weather conditions, the battery lifetime is superior to comparable products.

In the event of a change in system specifications, where the output power needs to be adjusted, the current consumption of the ATA5749 can be optimized accordingly. The active current consumption is scalable by output power programming via SPI in 1-dB steps. This enables designers to fine tune system performance, in particular, RF link budget versus battery life time.

In addition to output power adjustments, the SPI bus interface also enables the programming of other key parameters such as output frequency, FSK signal deviation, and CLK output frequency.

The ATA5749 operates at a maximum data rate of 40 kbit/s in FSK and ASK mode using Manchester coding, and at an RF frequency in the range of 300 to 450 MHz. The IC incorporates a robust crystal oscillator with fast start-up time of typically 200 us and a guaranteed parameter for negative resistance oscillation margin of 1,500 Ohm. This results in high reliability and helps avoid sleeping crystal issues. Only one 13.000000 MHz crystal type is needed for the standard frequency ranges 314.1 to 329.5 MHz and 424.5 to 439.9 MHz, resulting in nearly identical hardware board design for the regional RF modules, lower inventory costs, and reduced part number proliferation.

Availability and Pricing

Samples of the ATA5749 RF transmitter IC are available now in small-outline TSSOP10 packages. Pricing starts at US $1.25 for 10k-piece quantities. A demonstration board for development support is also available.


ASK = Amplitude Shift Keying
CLK = Clock
FSK = Frequency Shift Keying
PLL = Phase Locked Loop
RKE = Remote Keyless Entry
SPI = Serial Parallel Interface
TPMS = Tire Pressure Monitoring Systems

About Atmel

Atmel is a worldwide leader in the design and manufacture of microcontrollers, advanced logic, mixed-signal, nonvolatile memory and radio frequency (RF) components. Leveraging one of the industry's broadest intellectual property (IP) technology portfolios, Atmel is able to provide the electronics industry with complete system solutions focused on consumer, industrial, security, communications, computing and automotive markets.

Product information on Atmel's new PLL RF transmitter IC ATA5749 may be retrieved at:

Dr. Susanne van Clewe,
Marcom Manager Communications and Automotive Products
Phone: +49 7131 67-2081,

Note: The above text is the public part of the press release obtained from the manufacturer (with minor modifications). EETimes Europe cannot be held responsible for the claims and statements made by the manufacturer. The text is intended as a supplement to the new product presentations in EETimes Europe magazine.

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