AD8323 Datasheet | Analog Devices

a Features Supports DOCSIS Standard for Reverse Path Transmission Gain Programmable in 0.75 d B Steps Over a 53.5 d B Range Low Distortion at 60 d Bm V Output - 56 d Bc SFDR at 21 MHz - 55 d Bc SFDR at 42 MHz Output Noise Level - 48 d Bm V in 160 k Hz Maintains 75 ⍀ Output Impedance Power-Up and Power-Down Condition Upper Bandwidth: 100 MHz (Full Gain Range) 5 V Supply Operation Supports SPI Interfaces APPLICATIONS Gain-Programmable Line Driver HFC High-Speed Data Modems Interactive Set-Top Boxes PC Plug-in Modems General-Purpose Digitally Controlled Variable Gain Block VIN+ 5 V CATV Line Driver Fine Step Output Power Control AD8323 FUNCTIONAL BLOCK DIAGRAM VCC (7 PINS) BYP R1 VOUT+ BUFFER ATTENUATION CORE VIN- DIFF OR SINGLE INPUT AMP POWER AMP VOUT- ZOUT DIFF = 75⍀ POWER-DOWN LOGIC 8 R2 ZIN (SINGLE) = 800⍀ ZIN (DIFF) = 1.6k⍀ DECODE 8 DATA LATCH 8 SHIFT REGISTER DATEN DATA GND (11 PINS) SLEEP GENERAL DESCRIPTION DISTORTION - d Bc The AD8323 is a low-cost, digitally controlled, variable gain amplifier optimized for coaxial line driving applications such as cable modems that are designed to the MCNS-DOCSIS upstream standard. An 8-bit serial word determines the desired output gain over a 53.5 d B range resulting in gain changes of 0.7526 d B/LSB. The AD8323 prises a digitally controlled variable attenuator of 0 d B to - 53.5 d B, which is preceded by a low noise, fixed gain buffer and is followed by a low distortion high power amplifier. The AD8323 accepts a differential or single-ended input signal. The output is specified for driving a 75 Ω load, such as coaxial cable. Distortion performance...