Sunnyvale, Calif.Maxim Integrated Products has introduced the MAX1385/MAX1386/MAX11008 dual RF LDMOS bias controllers. At 7mm x 7mm, Maxim says these devices are the industry's smallest LDMOS bias controllers to integrate all of the analog-to-digital (A/D) and digital-to-analog (D/A) interfaces and logic functions required for cellular base-station control. The MAX1385/MAX1386/MAX11008 are suited to bias the power-amplifier power transistors employed in CDMA, GSM, EDGE, and UMTS cellular base-stations.
These bias controllers integrate all the functions needed in a PA signal chain to achieve 25microvolts (MAX1385/MAX1386) or 50microvolts (MAX11008) of resolution for self-calibration. The MAX1385/MAX1386 provide two gate-drive channels, each consisting of an 8-bit coarse DAC, a 10-bit fine DAC, and a gate-drive amplifier with a gain of 2 (MAX1385) or 4 (MAX1386). These channels generate a positive gate voltage to bias LDMOS devices, allowing up to 18 bits of resolution. Each of the MAX11008's two gate-drive channels integrates a 12-bit DAC to generate this positive gate voltage.
The MAX1385/MAX1386/MAX11008 offer a 7-channel, 12-bit ADC, which includes three channels for temperature measurement. In addition, each IC includes dual high-side current-sense amplifiers (32V, CMRR 90dB), which offer up to ±0.5% accuracy and 1 least-significant-bit (LSB) linearity at 12 bits. These high-side current-sense amplifiers feature programmable gains of 2, 10, and 25 to monitor the LDMOS drain current over the range of 20mA to 5A. The temperature sensor offers 0.25°C resolution with up to ±1°C accuracy.
Maxim Integrated Products, www.maxim-ic.com