(Products: Two-Way Radio ICs)
|Direct Conversion Transceiver IC for Narrow Band Radio Communication|
|Narrow Band Radio Communication: 6.25kHz / 7.5kHz / 12.5kHz / 15kHz / 20kHz / 25kHz / 50kHz / 100kHz / 150kHz / etc.|
Recently, commercial and public safety radios are becoming more multifunctional as it is shifting from analog to digital radio. In order to integrate various sensors into a digital radio, the market demand for minimizing PCB size is increasing. On the other hand, commercial and public safety radios require high selectivity, high linearity and high tolerance to spurious signals, still consisting of many discrete parts.
Asahi Kasei Microdevices Corporation, (AKM), has developed a transceiver IC, the AK2401, that integrates multiple components and provides high performance narrow-band radio communication. The AK2401 adopts direct conversion architecture which is advantageous for integration rather than the double superheterodyne architecture which was previously mainstream. This helps to miniaturize radio equipment. Moreover, a newly developed, "RDOC", (Real-time DC Offset Canceller), function achieves no characteristic deterioration due to DC offsets, (static or dynamic), which was a challenge for direct conversion architecture.
The receiver block of the AK2401 integrates an LNA, I/Q demodulator, PGA, and a 24-bit delta-sigma ADC. This achieves both high performance sensitivity and high tolerance to adjacent channel interference, intermodulation, and blocking. The AK2401 also integrates a delta-sigma Fractional-N synthesizer that composes a high performance PLL with an external VCO. The transmission block has a 12-bit DAC and a driver amplifier.
A major challenge in applying the direct conversion architecture to high-performance narrowband radio communication was in DC offset cancellation. Generally, when applying the high pass filter used for the direct conversion architecture to the narrowband radio, degradation of signal quality due to the loss of the signal component cannot be ignored. Therefore, AKM developed a proprietary technology that removes the DC offset in real time in response to changes in the surrounding radio wave environment, which is completely separate from the high pass filter. RDOC is performed internally and automatically with no requirement for external DSP programming. This will be more effective in an environment with low signal level, and contribute to the improvement of signal quality, (Bit Error Rate).
In addition to ten kinds of standard channel filters for Pass Band ranging from 2kHz to 60kHz, an FIR filter that can program arbitrary coefficients is available. A digital filter that’s able to change the bandwidth supports channel selection for multiple radio systems, enabling simple system designing for a radio platform.
AK2401Direct Conversion Transceiver IC for Narrow Band Radio Communication
|Operating Frequency||[MHz]||30 to 1200|
|LNA||Gain: 15dB, NF: 1.2dB, IIP3: +7dBm|
|Direct Conversion I/Q Demodulator||Gain: 42dB, NF: 16dB, IIP3: +19dBm|
|24-bit ΔΣ A/D Converter||Output Sampling Frequency:150kHz Max. (TCXO: 19.2MHz)|
|Variable Bandwidth Digital Filter||Bandwidth can be set arbitrarily|
|Function||Automatic Gain Control (AGC) function for LNA and PGA|
Real-time DC Offset Canceller (RDOC)
RSSI: Data read by SPI communication
|12-bit D/A Converter||Sampling Frequency: 200kHz Max, S/N: 72dB|
|Transmission Driver Amplifier Output||[dBm]||-6 to +6|
|Local Signal Dividing Circuit||Divide by 2 or more is recommended|
|TCXO Frequency||18.432 / 19.2 MHz are recommended|
|Power Supply||[V]||VDD1: 2.7 to 3.3|
CPVDD: 2.7 to 5.5
DACVDD: 2.7 to 5.5
|Operation Temperature||[°C]||-40 to 85|
|Package||52-pin QFN (7 x 7 x 0.85mm, 0.4mm pitch)|