Amplifier ICs
Volume 8, Issue 9 YOUR SEMICONDUCTOR SOLUTIONS RESOURCE

Dual-Channel, Digitally Controlled Gain Trim Amplifier for Broadband RF Designs

The AD8366 is a dual-channel, digitally controlled, gain trim amplifier with 0.25 dB step over a gain range of 4.5 to 20.5 dB. It is ideally suited for analog I/Q quadrature, ADC driving, and maintains excellent quadrature accuracy for direct conversion radio receivers. The device offers flat frequency performance and group delay from dc out to 150 MHz, independent of gain code. Fine gain control allows flexible and precise tuning to multistandard and wideband radio receivers. The AD8366 features include adjustable output common mode for matching to ADC input ranges and dc output offset correction loops to minimize demodulator dc offsets. It is available in a 32-lead LFCSP package and operates over the temperature range of -40°C to +85°C.

AD8366 Features

  • Gain range: 4.5 dB to 20.5 dB (steps of 0.25 dB)
  • Operating frequency: dc to 500 MHz
  • Bandwidth: 3 dB @ 800 MHz
  • NF: 10.5 dB @ 10 MHz max; 18 dB @ 10 MHz min
  • OIP3: 36 dBV rms @ 10 MHz
  • HD2, HD3 > 88 dBc for 2 V p-p output @ 10 MHz @ max gain
  • Differential input and output
  • Adjustable output common-mode
  • Serial and parallel port programmable
  • Single-supply: 5 V
  • AD8366: $6.75/1k

Single-Channel and Dual-Channel Variable Gain Amplifiers (VGAs) Provide 1 dB Resolution for Digital IF Automatic Gain Control (AGC) Applications

The AD8375 (single) and AD8376 (dual) digitally controlled variable gain amplifiers provide precise 1 dB gain control across a 24 dB range. Both amplifiers provide low distortion and high linearity with 50 dBm of output IP3, achieved through a proprietary distortion cancellation circuit. Both amplifiers are fully specified for IFs beyond 200 MHz. The devices consume 130 mA per channel and can be powered down to consume less than 5 mA from a single 5 V supply. They are available in 24-lead, 4 mm × 4 mm LFCSP and 32-lead, 5 mm × 5 mm LFCSP packages.

AD8375

AD8375 Features

  • Bandwidth: 690 MHz @ –3 dB
  • Gain range: –4 dB to 20 dB
  • Step size: 1 dB, ±0.2 dB
  • Differential input: 150 Ω
  • Differential output: open collector
  • Noise figure: 8 dB @ maximum gain
  • OIP3: 50 dBm at 140 MHz

Please click here for the Digitally Controlled Variable Gain Amplifiers selection table.

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