Low-power, low-noise analog-front-end IC targets ultrasound systems
By Paul Rako, Technical Editor -- EDN, March 27, 2008
Texas Instruments’ new family of analog-front-end ICs offers power consumption of only 122 mW, making it suitable for portable-system applications, and with noise performance of 0.85 nV/
at 2 MHz, making it applicable to high-channel-count, midrange medical-ultrasound machines. The parts also will find use in sonar and other applications. The device integrates eight channels of a low-noise amplifier; a voltage-controlled attenuator; programmable-gain amplifier; a lowpass filter, and a 12-bit, 50M-sample/sec ADC with LVDS (low-voltage-differential-signaling)-data outputs.
The resolution of a medical-ultrasound system depends on the number of channels it uses to acquire the information as well the noise level of those channels. A channel with lower noise allows better screen resolution. To save cost and power, portable ultrasound systems use 32 to 64 channels. High-end systems have 256 to 1024 channels. However, because of this device’s low power consumption, you can use it in systems with high channel counts, such as the portable systems in ambulances. With these devices, emergency-medical technicians see high-resolution ultrasound images, which they can wirelessly beam to the hospital emergency room. Capturing a high-quality image in the ambulance saves valuable time if it obviates the need for a patient rescan on the hospital’s high-end ultrasound machine.
The AFE5805 is available in a 15×9-mm, 135-pin BGA package with a suggested retail price of $75 (100). An evaluation module costs $199. Samples and evaluation modules are available now, and volume production scheduled for June 2008.
