AD8370AREZ

The AD8370 is a low cost, digitally controlled, variable gain amplifier (VGA) that provides precision gain control, high IP3, and low noise figure. The excellent distortion performance and wide bandwidth make the AD8370 a suitable gain control device for modern receiver designs. For wide input, dynamic range applications, the AD8370 provides two input ranges: high gain mode and low gain mode. A vernier, 7-bit, transconductance (gₘ) stage provides 28 dB of gain range at better than 2 dB resolution and 22 dB of gain range at better than 1 dB resolution. A second gain range, 17 dB higher than the first, can be selected to provide improved noise performance. The AD8370 is powered on by applying the appropriate logic level to the PWUP pin. When powered down, the AD8370 consumes less than 4 mA and offers excellent input to output isolation. The gain setting is preserved when operating in a power-down mode. Gain control of the AD8370 is through a serial 8-bit gain control word. The MSB selects between the two gain ranges, and the remaining 7 bits adjust the overall gain in precise linear gain steps. Fabricated on the ADI high speed XFCB process, the high bandwidth of the AD8370 provides high frequency and low distortion. The quiescent current of the AD8370 is 78 mA typically. The AD8370 amplifier comes in a compact, thermally enhanced 16-lead TSSOP package and operates over the temperature range of -40°C to +85°C.

Applications

• Differential ADC drivers
• IF sampling receivers
• RF/IF gain stages
• Cable and video applications
• SAW filter interfacing
• Single-ended-to-differential conversion

Key features

• Programmable low and high gain (2 dB resolution)
• Low range: −11 dB to +17 dB
• High range: 6 dB to 34 dB
• Differential input and output
• 200 Ω differential input
• 100 Ω differential output
• 7 dB noise figure @ maximum gain
• Two-tone IP3 of 35 dBm @ 70 MHz
• −3 dB bandwidth of 750 MHz
• 40 dB precision gain range
• Serial 8-bit digital interface
• Wide input dynamic range
• Power-down feature
• Single 3 V to 5 V supply