AD9877 Datasheet, PDF (2/36 Pages) Analog Devices – Mixed-Signal Front End Set-Top Box, Cable Modem

AD9877
TABLE OF CONTENTS
Specifications..................................................................................... 4
Absolute Maximum Ratings............................................................ 7
Explanation of Test Levels ........................................................... 7
Thermal Characteristics .............................................................. 7
ESD Caution.................................................................................. 7
Pin Configuration and Function Descriptions............................. 8
Typical Performance Characteristics ........................................... 10
Terminology .................................................................................... 12
Theory of Operation ...................................................................... 13
Transmit Section......................................................................... 13
Clock and Oscillator Circuitry ................................................. 14
Programmable Clock Output REFCLK................................... 15
Reset and Transmit Power-Down ............................................ 16
Σ-Δ Outputs ................................................................................ 17
Register Map and Bit Definitions ................................................. 18
Register 0x00—Initialization .................................................... 19
Register 0x01—Clock Configuration....................................... 19
Register 0x02—Power-Down.................................................... 19
Register 0x03–0x06—Σ-Δ Control Words.............................. 19
Register 0x08—ADC Clock Configuration ............................ 20
Register 0x0C—Die Revision.................................................... 20
Register 0x0D—Tx Frequency Tuning Words LSBs.............. 20
Register 0x0E—DAC Gain Control ......................................... 20
Register 0x0F—Tx Path Configuration ................................... 20
Registers 0x10–0x1F—Burst Parameter .................................. 20
Serial Interface for Register Control ............................................ 22
General Operation of the Serial Interface ............................... 22
Instruction Byte .......................................................................... 22
Serial Interface Port Pin Description....................................... 22
MSB/LSB Transfers .................................................................... 22
Notes on Serial Port Operation ................................................ 23
Transmit Path (Tx) ......................................................................... 24
Transmit Timing......................................................................... 24
Data Assembler........................................................................... 24
Half-Band Filters (HBFs) .......................................................... 24
Cascaded Integrator-Comb (CIC) Filter................................. 24
Combined Filter Response........................................................ 25
Tx Signal Level Considerations ................................................ 27
Tx Throughput and Latency ..................................................... 27
Digital-to-Analog Converter .................................................... 27
Programming the AD8321/AD8325 or AD8322/AD8327 Cable
Driver Amplifier Gain Control..................................................... 29
Receive Path (Rx) ........................................................................... 30
ADC Theory of Operation........................................................ 30
Receive Timing ........................................................................... 30
Driving the Analog Inputs ........................................................ 30
Op Amp Selection Guide .......................................................... 31
ADC Differential Inputs............................................................ 31
ADC Voltage References ........................................................... 32
PCB Design Considerations.......................................................... 33
Component Placement .............................................................. 33
Power Planes and Decoupling .................................................. 33
Ground Planes ............................................................................ 33
Signal Routing............................................................................. 34
Outline Dimensions ....................................................................... 35
Ordering Guide .......................................................................... 35
Rev. B | Page 2 of 36