Description

The AD8260 includes a high current driver, usable as atransmitter, and a low noise digitally programmable variablegain amplifier (DGA), useable as a receiver.The receiver section consists of a single-ended input preamplifier,and linear-in-dB, differential-output DGA. The receiver hasa small signal –3 dB bandwidth of 230 MHz; the driver smallsignal bandwidth is 195 MHz. The driver delivers ±300 mA,well suited for driving low impedance loads, even whenconnected to a 3.3 V supply.The AD8260 DGA is ideal for trim applications and has a gainspan of 30 dB, in 3 dB steps. Excellent bandwidth uniformity ismaintained across the entire frequency range. The low output-referrednoise of the DGA is advantageous in driving highspeed ADCs. The differential output facilitates the interface tomodern low voltage high speed ADCs.Single-supply and dual-supply operation makes the part versatileand enables gain control of negative-going pulses, such as thosegenerated by photodiodes or photo-multiplier tubes, as well asprocessing band-pass signals on a single supply. For maximumdynamic range, it is essential that the part be ac-coupled whenoperating on a single supply.The AD8260 preamplifier (PrA) is configured with externalresistors for gains greater than 6 dB and can be inverting ornoninverting. The DGA is characterized with a noninvertingpreamplifier gain of 2×. The attenuator has a range of 30 dB andthe output amplifier has a gain of 8× (18.06 dB). The lowestnoninverting gain range is −6 dB to +24 dB and shifts up withincreased preamplifier gain. The gain is controlled via a parallelport (Pin GNS0 to Pin GNS3) with 10 gain steps of 3 dB percode. The preamplifier and DGA are disabled for any code thatis not assigned a gain step.The AD8260 can operate with single or dual supplies from 3.3 Vto ±5 V. An internal buffer normally provides a split supplyreference for single-supply operation; an external reference canalso be used when the VMID buffer is shut down.The operating temperature range is −40°C to +105°C. TheAD8260 is available in a 5 mm × 5 mm, 32-lead LFCSP.Applications Digital AGC systems Tx/Rx signal processing Power line transceivers