SDAA206 March   2026 TAS2781

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Detailed Description
    1. 2.1 Typical Application Block Diagrams
    2. 2.2 Typical Schematics
      1. 2.2.1 External PVDDH Mode
      2. 2.2.2 Class-H Boosted Mode
      3. 2.2.3 TAS278X Power Modes
      4. 2.2.4 TAS278X Operational Modes
    3. 2.3 Layout Best Practices
      1. 2.3.1  DREG
      2. 2.3.2  IOVDD and IOVDD-SDW
      3. 2.3.3  AVDD
      4. 2.3.4  PVDDH
      5. 2.3.5  PVDDL
      6. 2.3.6  Class-D Outputs (OUTP and OUTN)
      7. 2.3.7  VSNSP and VSNSN
      8. 2.3.8  BSTP and BSTN
      9. 2.3.9  Ground Pins
      10. 2.3.10 Non-Soundwire Digital IO
      11. 2.3.11 Soundwire IO
  6. 3PCB Layers
  7. 4Summary
  8. 5References

Summary

Table 4-1 Design Guidelines Summary
Pin NumberPin NameSchematic ConsiderationsLayout Considerations
TAS2783A/TAS2785TAS2781
28PVDDHPVDDHConnect to 3s, 4s battery or boost converter output
Decouple to GND with 10uF+10uF+0.1uF at 25V
Use a wide trace to handle the high current
Place the capacitors as close to the device pin as possible
Make sure there is a short ground return path to pin 2, PGND. if no top layer GND plane is used. Pour a polygon around the ground side of the capacitors and use many vias to give a low impedance ground return path through layer 2.
27PVDDLPVDDLPWR_MODE0,1,3
connect to 1s battery, or 2.7V-5.5V DC-DC
Decouple to GND with 10 uF+0.1uF at 10
PWR_MODE2
Do not connect externally to a voltage
Decouple to GND with 1 uF+0.1uF at 6.3V
24AVDDAVDDConnect to 1.8V
Decouple to GND with 4.7uF at 6.3V
Place the capacitor as close to the pin 24 as possible. Connect the ground side of the capacitor to pin 25 on the top layer
20IOVDDIOVDDTAS2781
Connect to 1.8V or 3.3V
Decouple to GND with 1uF at 6.3V Rated.
TAS2783A/TAS2785
Connect to 1.2V, 1.8V or 3.3V
Decouple to GND with 2.2uF at 6.3V
Note: if Pin 17 and Pin 20 are sharing a supply voltage, the pins can be shorted together and a single 2.2uF capacitor can be used. This applies to TAS2781 and TAS2783A and TAS2785Place decoupling capacitors near device pin. Short ground side of the cap to the layer 2 ground plane with a via
17IOVDD-SDWNC_V1P8VIf pin 6,8,9 are used, ICC, SPI or Soundwire are used
TAS2781
Connect to 1.8V
Decouple to GND with 1uF at 6.3V.
TAS2783A/TAS2785
Connect to 1.2V or 1.8V
Decouple to GND with 2.2uF at 6.3V
10DREGDREGDecouple to GND with 1uF @ 6.3V
Do not connect externally to a supply or load
Place directly next to the device pin. There must be a short, direct, and low impedance path to pin 7 GND. Use vias on the ground side of the capacitor to layer 2 GND
1, 5VSNSN & VSNSPVSNSN & VSNSPShort to the speaker output after any LC Filter. Use 2.2kΩ 1% resistor in seriesRoute differentially and connect to the speaker connector. The 2.2kohm resistor placement is not critical. This trace carries no current. It can be as thin as allowed by the PCB fab.
3,29OUTP and OUTNOUTP and OUTNThis is a filter less class-D. LC filter is optional and only for EMI purposes. Use 120Ω ferrite bead and shunt 1nF capacitor if a filter is required.Route with wide traces to the speaker connection. Make VSNS connections as close to the speaker as possible. Keep the route short and place the EMI filter near the device to limit emissions.
4,30BSTP and BSTNBSTP and BSTNPlace a 100nF 10V capacitor between BSTP<->OUTP and BSTN<->OUTN. Connect the capacitor before any LC Filter.Both sides of this capacitor must have a low impedance connection. Place near the device. the capacitors can be placed on the bottom side of the PCM
26MODEMODEShort to AVDD - Soundwire Mode
Short to GND - I2C Mode
470 to GND - SPI Mode
Not critical. Do not allow mode pin connection to affect the AVDD routing.
23ADDRADDRShort to GND - SNDW UID 0x08 OR I2C Address 0x70
470Ω to GND - SNDW UID 0x09 OR I2C Address 0x72
470Ω to AVDD - SNDW UID 0x0A OR I2C Address 0x74
2.2kΩ to GND - SNDW UID 0x0B OR I2C Address 0x76
2.2kΩ to AVDD - SNDW UID 0x0C OR I2C Address 0x78
10kΩ to GND - SNDW UID 0x0D OR I2C Address 0x7A
10kΩ to AVDD - SNDW UID 0x0E OR I2C Address 0x7C
Short to AVDD - SNDW UID 0x0F OR I2C Address 0x7E
Not Critical. Do not allow ADDR pin connection to affect the AVDD routing.
11PWM_CTRLPWM_CTRLConnect to LC filter then boost feedback pin. Refer to {link to sloa326} for design guidance on the Class-H boost. Leave floating if unusedNot critical
21IRQzIRQzIn I2C or SPI Modes
Pull up to IOVDD with 20kΩ .
Connect to SoC GPIO to monitor device interrupt
In SNDW Mode
Pull up to IOVDD with 20kΩ even if unused.
Not critical
22SDzSDzConnect to the SoC GPIONot critical
25,2,7DGND, PGND, GNDDGND, PGND, GNDShort to board groundPlace a ground polygon under the device package on the top layer. Short pins 2,7, and 25 to this polygon, and use multiple vias to short that polygon to the Layer 2 GND plane
The Layer directly under the top layer must be dedicated to ground.
16NCNCShort to board groundNot critical
6SWDATA1ICCI2C/SPI Modes
Short ICC between two L and R channel devices
Float if unused
Soundwire mode (TAS2783A/TAS2785)
Connect to the host data lane 1
Short to GND if unused
In Soundwire mode

Control the impedance to 50 Ohms
Length match the trace segments of clock and data between Host <-> Device, and Device <-> Device
Do not route near any high current or switching signals, such as PVDDH, PVDDL, OUTP, OUTN, BSTP, BSTN,VSNSP,VSNSN
8SWDATA0NC_SDOSPI Mode
Connect to host SPI data in Soundwire mode

Connect to the host data lane 0Short to ground if unused
9SWCLKNC_SCLKSPI Mode
Connect to host SPI clock output
Soundwire mode
Connect to host Soundwire clock output
18SCLSCL_nSCSI2C Mode
Pull up to IOVDD with resistor
SPI Mode
Connect to host SPI chip select
Soundwire Mode
Pull up to IOVDD even if unused
Do not route near any high current or switching signals, such as PVDDH, PVDDL, OUTP, OUTN, BSTP, BSTN, VSNSP,VSNSN
19SDASDA_SDII2C Mode
Pull up to IOVDD with resistor
SPI Mode
Connect to host SPI data output
Soundwire Mode
Pull up to IOVDD even if unused
12SDOUTSDOUTConnect to host
Leave floating if unused
13,14,15SDIN, FSYNC, SBCLKSDIN, FSYNC, SBCLKConnect to host
Connect to ground if unused