RF Amplifier Gain and Gain Flatness

01 / ENGINEERING REVIEW

Estimate input drive

Small-signal power gain in dB = output power in dBm − input power in dBm. For example, 30 dB gain with −10 dBm input gives approximately 20 dBm output while the amplifier remains in its linear region. Near compression, this simple estimate overstates output.

02 / ENGINEERING REVIEW

Read the limits

Check whether gain is minimum or typical, and whether it is measured at a specified input level, supply and temperature. Never use small-signal gain to infer maximum permissible input power.

03 / ENGINEERING REVIEW

Understand flatness

Gain flatness describes variation across a stated frequency range. A ±dB limit and a peak-to-peak limit use different conventions. Confirm the reference and test conditions before comparing numbers.

04 / ENGINEERING REVIEW

Check the complete path

• Source output and cable/attenuator losses.
• Gain over the full required band.
• Compression and maximum input limits.
• Changes with temperature or supply.
• Any required gain-control range.

Open HD30174 and its current datasheet for a model-level review. For an RFQ, include your available drive level and desired output, not just the gain target.