Gain differential amplifier broadens usefulness and performance in range of applications

Linear Technology’s LTC6432-15 is a wideband fully differential amplifier with 15dB gain, offering linearity of up to +50.3dBm OIP3 (output third-order intercept), very high OP1dB (output 1dB compression point) of +22.7dBm, and 3.2dB noise figure at 150MHz. In addition to its outstanding signal-to-noise at high frequencies, it maintains its dynamic range performance even at lower frequencies. That is because the device’s advanced SiGe bipolar design exhibits significantly lower 1/f noise frequency corner than that of GaAs or pHEMT FET based amplifiers. Hence its noise figure rises to only 6.6dB at 100kHz, compared to more than 20dB for other amplifiers. The device effectively extends the useful bandwidth and dynamic range performance for many applications that process low frequency signals. Moreover, the device achieves superior stability over temperature, power supply ranges and from device to device compared to GaAs and pHEMT amplifiers. The device’s high dynamic range and extended bandwidth to low frequencies broaden its usefulness and improve performance in a wide range of amplifier applications including high sample rate A/D converter drivers, cable network amplifiers, broadband signal source conditioning, radar receiver IF amplifiers, software defined radio, VHF/UHF broadcast radios and RF test instruments. The device differential inputs and outputs are internally 100ohm terminated. Its inputs are matched from 100kHz to 1.4GHz, with better than 10dB return loss over the full bandwidth. The output is also matched from 100kHz to 1GHz. The amplifier needs only DC blocking capacitors at its inputs and outputs, two chokes for proper biasing, plus one feedback capacitor per output to extend its excellent gain flatness to low frequencies. The device operates from a single 5V supply. It draws a nominal 166mA supply current. The device is specified for operation over a case temperature range from –40C to 85C.