Datasheet AD2420(W), AD2426(W), AD2427(W), AD2428(W), AD2429(W) (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | Automotive Audio Bus A2B Transceiver |
| Pages / Page | 38 / 3 — AD2420(W). AD2426(W). /AD2427(W). /AD2428(W). AD2429(W). GENERAL … |
| Revision | B |
| File Format / Size | PDF / 2.1 Mb |
| Document Language | English |
AD2420(W). AD2426(W). /AD2427(W). /AD2428(W). AD2429(W). GENERAL DESCRIPTION. Table 1. Product Comparison Guide. Feature. AD2420/
Model Line for this Datasheet
Text Version of Document
AD2420(W) / AD2426(W) /AD2427(W) /AD2428(W) / AD2429(W) GENERAL DESCRIPTION
The Automotive Audio Bus (A2B®) provides a multichannel, The transceiver can connect directly to general-purpose digital I2S/TDM link over distances of up to 15 m between nodes. It signal processors (DSPs), field-programmable gate arrays embeds bidirectional synchronous pulse-code modulation (FPGAs), application specific integrated circuits (ASICs), (PCM) data (for example, digital audio), clock, and synchroni- microphones, analog-to-digital converters (ADCs), digital-to- zation signals onto a single differential wire pair. A2B supports a analog converters (DACs), and codecs through a multichannel direct point to point connection and allows multiple, daisy- I2S/TDM interface. It also provides a pulse density modulation chained nodes at different locations to contribute and/or con- (PDM) interface for direct connection of up to four PDM digital sume time division multiplexed (TDM) channel content. microphones. A2B is a single-master, multiple-slave system where the trans- Finally, the transceiver also supports an A2B bus powering fea- ceiver at the host controller is the master. The master generates ture, where the master node supplies voltage and current to the clock, synchronization, and framing for all slave nodes. The slave nodes over the same daisy-chained, twisted pair wire cable master A2B transceiver is programmable over a control port as used for the communication link. (I2C) for configuration and read back. An extension of the con- trol port protocol is embedded in the A2B data stream, which grants direct access of registers and status information on slave transceivers as well as I2C to I2C communication over distance.
Table 1. Product Comparison Guide Feature AD2420/
AD2426/
AD2427/
AD2428/
AD2429/
AD2420W AD2426W AD2427W AD2428W AD2429W
Master capable No No No Yes Yes Number of slaves discoverable1 N/A N/A N/A Up to 10 Up to 2 Functional TRX blocks A only A only A + B A + B B only I2S/TDM support No No No Yes Yes PDM microphone inputs 2 mics2 4 mics 4 mics 4 mics 4 mics Max node to node cable length 5 m 15 m 15 m 15 m 5 m 1 N/A means not applicable. 2 PDM microphones must be connected to the DRX0/IO5 pin. Rev. B | Page 3 of 38 | January 2020 Document Outline Automotive Audio Bus A2B Transceiver A2B Bus Features A2B Transceiver Features Applications Table of Contents Revision History General Description A2B Bus Details I2C Interface I2S/TDM Interface I2S Reduced Rate Pulse Density Modulation (PDM) Interface GPIO Over Distance Mailboxes Data Slot Exchange Between Slaves Clock Sustain State Programmable Settings to Optimize EMC Performance Programmable LVDS Transmit Levels Spread-Spectrum Clocking Unique ID Support for Crossover or Straight Through Cabling Data Only and Power Only Bus Operation Specifications Operating Conditions Electrical Characteristics Power Supply Rejection Ratio (PSRR) Timing Specifications Power-Up Sequencing Restrictions A2B Bus System Specification RMS Time Interval Error (TIE) Jitter PDM Typical Performance Characteristics Absolute Maximum Ratings Thermal Characteristics ESD Caution Test Circuits and Switching Characteristics Output Drive Currents Test Conditions Output Enable Time Measurement Output Disable Time Measurement Capacitive Loading Pin Configuration and Function Descriptions Power Analysis Current Flow Constant Current PLL Supply Current VIN Quiescent Current IOVDD Current Peripheral Supply Current Digital Logic Supply Current A2B Bus TX/RX Current LVDS Transmitter and Receiver Supply Currents Downstream/Upstream Activity Level LVDS Transmitter and Receiver Idle Current VREG1 and VREG2 Output Currents Current at VIN (IVIN) Power Dissipation Resistance Between Nodes Voltage Regulator Current in Master Node or Local Powered Slave Node Power Dissipation of A2B Bus Power Analysis of Bus Powered System Supply Voltage Reducing Power Consumption Power-Down Mode Standby Mode Control Mode Thermal Power Designer Reference VSENSE and Considerations for Diodes Optional Add On Circuits Layout Guidelines Outline Dimensions Automotive Products Ordering Guide
The Automotive Audio Bus (A2B®) provides a multichannel, The transceiver can connect directly to general-purpose digital I2S/TDM link over distances of up to 15 m between nodes. It signal processors (DSPs), field-programmable gate arrays embeds bidirectional synchronous pulse-code modulation (FPGAs), application specific integrated circuits (ASICs), (PCM) data (for example, digital audio), clock, and synchroni- microphones, analog-to-digital converters (ADCs), digital-to- zation signals onto a single differential wire pair. A2B supports a analog converters (DACs), and codecs through a multichannel direct point to point connection and allows multiple, daisy- I2S/TDM interface. It also provides a pulse density modulation chained nodes at different locations to contribute and/or con- (PDM) interface for direct connection of up to four PDM digital sume time division multiplexed (TDM) channel content. microphones. A2B is a single-master, multiple-slave system where the trans- Finally, the transceiver also supports an A2B bus powering fea- ceiver at the host controller is the master. The master generates ture, where the master node supplies voltage and current to the clock, synchronization, and framing for all slave nodes. The slave nodes over the same daisy-chained, twisted pair wire cable master A2B transceiver is programmable over a control port as used for the communication link. (I2C) for configuration and read back. An extension of the con- trol port protocol is embedded in the A2B data stream, which grants direct access of registers and status information on slave transceivers as well as I2C to I2C communication over distance.
Table 1. Product Comparison Guide Feature AD2420/
AD2426/
AD2427/
AD2428/
AD2429/
AD2420W AD2426W AD2427W AD2428W AD2429W
Master capable No No No Yes Yes Number of slaves discoverable1 N/A N/A N/A Up to 10 Up to 2 Functional TRX blocks A only A only A + B A + B B only I2S/TDM support No No No Yes Yes PDM microphone inputs 2 mics2 4 mics 4 mics 4 mics 4 mics Max node to node cable length 5 m 15 m 15 m 15 m 5 m 1 N/A means not applicable. 2 PDM microphones must be connected to the DRX0/IO5 pin. Rev. B | Page 3 of 38 | January 2020 Document Outline Automotive Audio Bus A2B Transceiver A2B Bus Features A2B Transceiver Features Applications Table of Contents Revision History General Description A2B Bus Details I2C Interface I2S/TDM Interface I2S Reduced Rate Pulse Density Modulation (PDM) Interface GPIO Over Distance Mailboxes Data Slot Exchange Between Slaves Clock Sustain State Programmable Settings to Optimize EMC Performance Programmable LVDS Transmit Levels Spread-Spectrum Clocking Unique ID Support for Crossover or Straight Through Cabling Data Only and Power Only Bus Operation Specifications Operating Conditions Electrical Characteristics Power Supply Rejection Ratio (PSRR) Timing Specifications Power-Up Sequencing Restrictions A2B Bus System Specification RMS Time Interval Error (TIE) Jitter PDM Typical Performance Characteristics Absolute Maximum Ratings Thermal Characteristics ESD Caution Test Circuits and Switching Characteristics Output Drive Currents Test Conditions Output Enable Time Measurement Output Disable Time Measurement Capacitive Loading Pin Configuration and Function Descriptions Power Analysis Current Flow Constant Current PLL Supply Current VIN Quiescent Current IOVDD Current Peripheral Supply Current Digital Logic Supply Current A2B Bus TX/RX Current LVDS Transmitter and Receiver Supply Currents Downstream/Upstream Activity Level LVDS Transmitter and Receiver Idle Current VREG1 and VREG2 Output Currents Current at VIN (IVIN) Power Dissipation Resistance Between Nodes Voltage Regulator Current in Master Node or Local Powered Slave Node Power Dissipation of A2B Bus Power Analysis of Bus Powered System Supply Voltage Reducing Power Consumption Power-Down Mode Standby Mode Control Mode Thermal Power Designer Reference VSENSE and Considerations for Diodes Optional Add On Circuits Layout Guidelines Outline Dimensions Automotive Products Ordering Guide
