Analog Devices IC Monitors Wireless Base Stations
Analog Devices has addressed the need for monitoring current, voltage and temperature in wireless base stations with the AD7294, which provides the complete analog-to-digital (A/D) and digital-to-analog (D/A) interfaces required for base station control in CDMA, GSM, EDGE and UMTS systems. In addition, the AD7294 complies with the high-voltage requirements of wireless base stations in a single chip, thus reducing overall component count and cost.
Targeted at wireless infrastructure applications, the AD7294 multichannel input/output (I/O) data converter integrates all the functions required for the monitoring and control of current, voltage and temperature in a single chip. As output power and channel count grow in wireless base station designs, the importance of controlling bias current and operating conditions in power transistors increases in order to optimize overall power efficiency, adjacent channel interference and signal-to-noise performance.
The AD7294 integrates a 4-channel, 12-bit DAC; a 9-channel, 12-bit ADC; two high-side current-sense amplifiers; and three temperature sensor channels. As a result, the AD7294 reduces component count and cost, as well as improving reliability and ease-of-use for designers of wireless base stations. This level of integration was achieved, in part, through a proprietary CMOS process developed at ADI, which combines high-voltage capability with high-speed, low-power converter cores.
The AD7294 provides higher levels of accuracy and performance as compared to previous solutions. The integrated high-side current sensor is compliant with high-voltage requirements, operating up to a maximum of 48 V, offering 0.5 percent accuracy and 1-LSB linearity at 12 bits, while the temperature sensors offer 0.25 ° C resolution with ±2 ° C accuracy. AD7294 designs are less complex compared to existing solutions, which require an external amplifier for the high-voltage compliance. In addition, the higher accuracy translates to tighter control of power transistor biasing, thereby achieving better signal integrity and power efficiency in wireless base stations.
The AD7294 is available now. It is priced at $9.00 per unit in 1,000-piece quantities and is available in two package options: a 56-lead LFCSP (lead-frame chip-scale package) and a 64-lead TQFP (thin quad flat pack). Both packages are specified over the extended industrial temperature range (-40 ° C to +105 ° C).
