Texas Instruments has introduced two low power, 12bit AFEs (analogue front ends) for femtocell base stations and heterodyne or direct-conversion radio architectures. The AFE7225 integrates a dual 125Msamples/s ADC and dual 250Msamples/s DAC. It increases the SNR and provides high DAC output current, according to the company. The device is available for low bandwidth, power-sensitive applications. It integrates a dual 65Msamples/s ADC and dual 130Msamples/s DAC, and uses 398mW in full-duplex or 212mW in half-duplex receive mode at full speed. Both AFEs feature independent transmit and receive, 32bit numerically controlled oscillators, serialised LVDS I/O options, and independent transmit and receive quadrature modulation correction for gain, phase and offset imbalances. They consume 12mW of power in deep sleep mode with 13µs wake up time, or 120mW in light sleep mode with 5µs wake-up time. Dual ADC achieves 70dB SNR, while the dual DAC achieves an adjacent channel leakage ratio of 75dB with a 3G W-CDMA cellular signal. Digital DAC inputs and ADC outputs can be configured for serial LVDS to save pin trace-count and aid long-trace signaling; or multiplexed 12bit CMOS for a low-power interface, supporting full-duplex over two buses or half-duplex from one or two digital buses. Both devices are housed in a 9x9mm QFN package.
