Austrian supplier Austriamicrosystems has readied a multi-channel narrowband RF transmitter chip that meets numerous worldwide standards. The AS3977 is an automotive-qualified ARIB transmitter application-specific standard product(ASSP) that offers increased reliability of data transfer with support of FDMA and TDMA modes for redundant data transmission over distances up to one mile.

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ARIB (The Association of Radio Industries and Businesses) is Japan's standards development organization for radio technology. AS3977 is compliant with ARIB standard STD-T67 for multi-channel narrowband applications in Japan. It also supports all FCC (Federal Communications Commission) and ETSI (European Telecommunications Standards Institute) standards relevant for use in the United States and Europe.

The transmitter is optimal for use in remote keyless entry (RKE) car access control systems. Due to its temperature resistance up to 125°C, combined with low power operation modes, it is also recommended for tire pressure monitoring (TPM) applications. Numerous other applications include short-range devices, digital radio transmission, remote control units, cordless alarm systems, remote metering and low-power telemetry.

Based on 0.35-micron SiGe biCMOS process, the AS3977 is a low-power, fully integrated frequency shift key (FSK)/amplitude shift key (ASK) transmitter capable of operating at any user-selected ISM frequency from 300 to 1000 MHz. FSK capabilities offer enhanced reliability in data transmission due to increased noise and interference resistance. The AS3977 is based on a sigma-delta-controlled fractional-N synthesizer phase-locked loop (PLL) with a fully integrated voltage-controlled oscillator. The power amplifier output is programmable, capable of delivering from -20 dBm to 8 dBm. An on-chip, low drop-out regulator is available for accurate output power independent of supply voltage variation. It can support data rates up to 100 kbps, depending on required filtering.

The AS3977 includes a reference frequency generator, including a crystal oscillator providing the comparison frequency of the PLL and a high-precision clock output. A programmable fractional-N synthesizer with a step width of less than 100 Hz generates the RF output. The output signal can be shaped by a Gaussian filter to minimize the occupied bandwidth and adjacent-channel power. A subsequent power amplifier amplifies the RF signal and delivers the RF to a single-ended antenna. Additional on-chip antenna tuning capacitors optimize the output power.

Additional features include 2.0-3.6 V power supply range, 4 kV ESD protection (2 kV for the RF pins), filtered FSK or ASK, FSK deviation programmable up to 64 kHz, integrated loop filter, 12 to 20 MHz crystal oscillator, digital lock detector and low power-down current consumption. The AS3977 is available in ultra-small QFN16 packages at prices starting from $1.25 for 100,000 units.