AGC loop and receiver front-end fit
The LMH6505MM/NOPB is a single-channel variable gain amplifier (VGA) from Texas Instruments, designed for automatic gain control (AGC) loops in receiver chains and test equipment. Its 150 MHz -3dB bandwidth and 1500 V/µs slew rate mean it can handle fast-rising IF signals without introducing slew-rate limiting distortion — the output settles cleanly on a 2 V step in under 1.5 ns, which keeps the error vector magnitude low in a QAM demodulator. The gain-control input accepts a differential voltage that sets the gain over a 0 dB to 40 dB range (nominal is not absolute max — stay inside the supply rails on the control pin per the datasheet).
Supply current, output drive, and thermal budget
Quiescent supply current is 11 mA typical from a single 7 V to 12 V rail — the total power dissipation at 12 V is 132 mW, which keeps the junction temperature below 50°C above ambient in still air. The 80 mA output current per channel can drive a 50-ohm load to ±3 V without an external buffer, but the output swing is limited by the supply headroom; at 7 V the peak-to-peak swing into 50 ohms drops to about 4 V.