AD8320 Datasheet | Analog Devices

a Features 8-Bit Serial Gain Control V/V/LSB Linear Gain Response 36 d B Gain Range ؎0.20 d B Gain Accuracy Upper Bandwidth: 150 MHz 22 d Bm 1 d B pression Point (75 ⍀ ) Drives Low Distortion Signals into 75 ⍀ Load: - 57 d Bc SFDR at 42 MHz and 12 d Bm Out - 46 d Bc SFDR at 42 MHz and 18 d Bm Out Single Supply Operation from 5 V to 12 V Maintains 75 ⍀ Output Impedance Power-Up and Power-Down Condition Supports SPI Input Control Standard APPLICATIONS Coaxial Cable Driver HFC Cable Telephony Systems HFC High Speed Data Modems Interactive Set-Top Boxes PC Plug-In Modems Interfaces with AD9853 I2C Controlled Digital Modulator High Performance Digitally Controlled Variable Gain Block Serial Digital Controlled Variable Gain Line Driver AD8320 FUNCTIONAL BLOCK DIAGRAM VCC GND PWR AMP REFERENCE VOUT VREF VIN INV. ATTENUATOR CORE REVERSE AMP BUF. DATA LATCH POWERDOWN/ SWITCH INTER. PD DATA SHIFT REGISTER DATEN CLK SDATA DESCRIPTION The AD8320 is a digitally controlled variable gain amplifier optimized for coaxial line driving applications. An 8-bit serial word determines the desired output gain over a 36 d B range (256 gain levels). The AD8320 provides linear gain response. The AD8320 is made up of a digitally controlled variable attenuator of 0 d B to - 36 d B, which is preceded by a low noise, fixed gain buffer and followed by a low distortion high power amplifier. The AD8320 has a 220 Ω input impedance and accepts a single-ended input signal with a specified analog input level of up to 0.310 V p-p. The output is specified for driving a 75 Ω load, such as coaxial cable, although the AD8320 is capable of driving other loads. Distortion performance of - 57 d Bc is achieved with an output level up to 12 d Bm (3.1 V p-p) at 42 MHz, while - 46 d Bc distortion is achieved with an output level up to 18 d Bm (6.2 V p-p). A key performance and cost advantage of the AD8320 results from the ability to maintain a constant 75 Ω output impedance during power-up and power-down...