Texas Instruments TAS2574 User manual

EVM User's Guide: TAS2574 TAS2574EVM
TAS2574 Evaluation Module
Description
The TAS2574EVM has been designed to demonstrate
the performance of TAS2574 in a dual-mono
configuration. This tool utilizes the AC-MB
motherboard to provide an interface and supply
voltages to the EVM daughter card. Up to four devices
can share a common bus through I2S/TDM + I2C
interfaces; two EVMs can be mounted one on top of
each other, as shown in Section 2.8.
Get Started
1. Download TAS2574 data sheet.
2. Order the EVM at TAS2574 product folder.
3. Request access and download PPC3 from
TAS2574 product folder.
4. Visit and ask questions at e2e forum.
Features
• Mono or dual-mono speaker evaluation
• Interface using PurePath Console 3 Windows®
software
• EVM interconnection for up to 4 audio channels
• USB input
• External I2C and I2S/TDM host controller
connection available
Applications
•Mobile Phone, Tablets and Wearables
•Smart Speakers with Voice Assistance
•Bluetooth and Wireless Speakers
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1 Evaluation Module Overview
1.1 Introduction
This user's guide describes the function and use of the TAS2574EVM. This document includes the hardware
configuration instructions, a quick-start guide, jumper and connector descriptions, software description,
schematics, and printed circuit board (PCB) layout that demonstrate TI's recommended practices for these
devices.
This section provides details on what is included inside the evaluation module box, what are TAS2574
capabilities and operation ranges, as well as what is the additional test equipment that can be required for
a full audio evaluation.
1.2 Kit Contents
The evaluation kit consists of the following items:
• TAS2574EVM
• AC-MB controller board
A speaker is not included in the kit, however any speaker can be connected to each of the amplifiers outputs
using the banana jacks or screw headers.
Similarly, a power supply is not part of the kit, but the barrel jack connector can be connected to any power
supply in a range of 2.4V to 5.5V.
1.3 Specification
The TAS2574 is a digital input Class-D audio amplifier optimized for delivering best battery life for real use case
of music playback and voice calls.
The integrated boost operation is flexible so that TAS2574 can be implemented in 1S, 2S and 3S battery
applications. TAS2574EVM showcases the 1S battery broadly used in mobile and industrial applications.
TAS2572
OUT_P
OUT_N
VBAT
BGND
GND
IOVDD
PGND
VDD
PVDD
VSNS_N
VSNS_P
SW
VDD
1.65 V - 1.95 V
GREG
DREG
SDZ
AD1
IRQZ
IOVDD
1.2 V / 1.8 V
C3
2.2 µF
C6
0.1 µF
R1
R2 C11
C10
L2
L3
Optional Components if EMI
filtering is required
AD2
C2
1 µF
C1
1 µF
VBAT
2.5 V - 5.5 V
C4
1 µF
VBAT_SNS
(opt.)
L1
1 µF
C5
10 µF
C9
0.1 µF
C7
10 µF
C8
10 µF
3
3
IOVDD
I2S
4
I2C
2
3 4 3
Figure 1-1. Application Diagram for 1 S Battery System
For 2 S battery applications, the boost inductor can be supplied by a higher supply from 4.5V to 9 V. VBAT pin is
still supplied by a voltage from 2.5V to 5.5V.
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TAS2572
OUT_P
OUT_N
VBAT
BGND
GND
IOVDD
PGND
VDD
PVDD
VSNS_N
VSNS_P
SW
VDD
1.65 V - 1.95 V
GREG
DREG
SDZ
AD1
IRQZ
IOVDD
1.2 V / 1.8 V
C3
2.2 µF
C6
0.1 µF
R1
R2 C11
C10
L2
L3
Optional Components if EMI
filtering is required
AD2
C2
1 µF
C1
1 µF
VDD_5V
3.0 V - 5.5 V
C4
1 µF
VBAT_SNS
(opt.)
L1
1 µF
C5a
10 µF
C9
0.1 µF
C7
10 µF
C8
10 µF
3
3
IOVDD
I2S
4
I2C
2
3 4 3
VBAT2S
4.5 V - 9.0 V
Figure 1-2. Application Diagram for 2 S Battery System
In a 3 S battery application, the integrated boost can be bypassed, and an external power rail up to 14 V can
supply PVDD directly. The boost inductor is not required in this case and SW pins are left open. VBAT pin is still
supplied by a voltage from 2.5V to 5.5V.
TAS2572
OUT_P
OUT_N
VBAT
BGND
GND
IOVDD
PGND
VDD
PVDD
VSNS_N
VSNS_P
SW
VDD
1.65 V - 1.95 V
GREG
DREG
SDZ
AD1
IRQZ
IOVDD
1.2 V / 1.8 V
C3
2.2 µF
C6
0.1 µF
R1
R2 C11
C10
L2
L3
Optional Components if EMI
filtering is required
AD2
C2
1 µF
C1
1 µF
VDD_5V
2.5 V - 5.5 V
C4
1 µF
VBAT_SNS
(opt.)
C9
0.1 µF
C7
10 µF
3
3
IOVDD
I2S
4
I2C
2
3 4 3
PVDD (ext.)
(VBAT - 14 V)
Figure 1-3. Application Diagram for 3 S Battery System
1.4 Device Information
TAS2574 is a mono, digital-input, Class-D audio amplifier optimized for efficiently driving high peak power into
small loudspeaker applications. The Class-D amplifier is capable of delivering 6W of max average power into 8
Ω load at a battery voltage of 4.2 V. Integrated speaker voltage and current sense provides real time monitoring
of loud speakers. Up to four devices can share a common bus via I2S/TDM + I2C interfaces.
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2 Hardware
2.1 AC-MB Settings
2.1.1 Audio Serial Interface Settings
The AC-MB provides the digital audio signals to the evaluation module from the USB, optical connector, stereo
jack, and external audio serial interface (ASI) header. Figure 2-1 shows a block diagram of the ASI routing on the
AC-MB.
MUX
USB
Optical Input
Stereo Analog
Input
External ASI Header
Source
Selector
(SW2)
Audio
Processor
PCM921 1Optical Output
To EVM
Figure 2-1. AC-MB Audio Serial Interface Routing
Switch SW2 on the AC-MB selects the audio serial bus that interfaces with the TAS2574EVM daughter card.
Next to switch SW2, the AC-MB has a quick reference table to identify the audio serial interface source options
and switch settings. The AC-MB acts as the controller for the audio serial interface, with three different modes of
operation: USB, optical or analog, or external ASI.
2.1.2 USB
The serial interface clocks and data are provided from the USB interface. The sampling rate and format are
determined by the USB audio class driver on the operating system.
The default settings for the USB audio interface are 32-bit frame size, 48-kHz sampling rate, BCLK and FSYNC
ratio is 256, and the format is time division multiplexing (TDM).
The AC-MB is detected by the OS as an audio device with the name TI USB Audio UAC2.0. Figure 2-2
illustrates the AC-MB audio setting for the USB mode of operation.
Figure 2-2. AC-MB USB Audio Setting
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2.1.3 External
In this mode, the audio serial interface clocks for the evaluation board are provided through connector J7 from
an external source. This architecture allows the use of an external system to communicate with the evaluation
board, such as a different host processor or test equipment (for instance, Audio Precision PSIA). The clocks
generated from the USB interface and PCM9211 are isolated with this setting. Figure 2-3 shows the AC-MB
audio setting for the external mode of operation.
Figure 2-3. AC-MB External Audio Setting
Figure 2-4 shows how to connect the external audio interface, with the bottom row for the signal and the top row
for ground.
Figure 2-4. AC-MB Connection with External Audio Serial Interface
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2.2 AC-MB Power Supply
The AC-MB motherboard is powered from a single 5-V power supply. However, the motherboard has different
low-dropout regulators (LDOs) integrated that provide the required power supplies to the different blocks of
the board. Figure 3-1 shows a block diagram depicting the power structure of the AC-MB. The AC-MB can
be powered from the host computer by using the USB 5-V power supply (VBUS) by shorting header J5, USB
POWER. Additionally, the AC-MB can be powered from an external power supply connected to terminal J4,
EXTERNAL POWER. Header J5 must be open for external supply operation. The IOVDD voltage for the digital
signals that is provided to the evaluation module is generated on the motherboard from the main power supply
(USB or external). The voltage levels available are 1.2V, 1.8V and 3.3V, and can be selected via the J3 header
IOVDD. Default setting for TAS2574EVM operation is 1.8V; 3.3V operation cannot be used for TAS2574EVM.
When the motherboard is fully powered and the power supplies from the onboard LDOs are correct, the
green POWER LED (D3) turns ON. The USB READY LED indicates that a successful USB communication is
established between the AC-MB and the host computer.
Figure 2-5. Power -Supply Distribution of the AC-MB
2.3 Default Jumper Setting on TAS2574EVM
Figure 4-1 given below illustrates all the default jumper settings for TAS2574EVM.
Figure 2-6. Default Jumper Settings
Table 4-1 shows the default positions for all the jumpers on TAS2574EVM.
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Table 2-1. Default Jumper Settings
Jumper Setting Description
J7 Insert IOVDD current sense for U1
J8 Insert AVDD current sense for U1
J29 DNI External VBST for U1
J6 Insert VBAT pin current sense for U1
J93 Insert SDOUT break for U1
J82 Insert SDIN break for U1
J71 Insert RST break for U1
J60 Insert SBCLK break for U1
J50 Insert FSYNC break for U1
J13 Insert INT break for U1
J91 Insert SDA break for U1
J92 Insert SCL break for U1
J56 Insert (1-2) VBAT source selector for U1
J28 Insert (2-3) VBAT_SNS selector for U1
J39 Insert VBAT source from barrel jack for U1
J46 Insert VBAT source from barrel jack for U1
J34 Insert IOVDD current sense for U2
J35 Insert AVDD current sense for U2
J32 DNI External VBST for U2
J33 Insert VBAT pin current sense for U2
J97 Insert SDOUT break for U2
J96 Insert SDIN break for U2
J100 Insert RST break for U2
J94 Insert SBCLK break for U2
J95 Insert FSYNC break for U2
J14 Insert INT break for U2
J99 Insert SDA break for U2
J98 Insert SCL break for U2
J57 Insert (1-2) VBAT source selector for U2
J52 Insert (2-3) VBAT_SNS selector for U2
J41 Insert VBAT source from barrel jack for U2
J49 Insert VBAT source from barrel jack for U2
J74 DNI EEPROM write protect
J51 DNI EEPROM address selector
J37-4-9 IOVDD_MB Buffer source selector
J38-5-2 IOVDD_MB IOVDD source selector for U1 and U2
J36-11-10 IOVDD_MB AVDD source selector for U1 and U2
J45 Insert (2-3) 1.8V LDO source selector
J19 Insert I2C pull-up connect
J20 Insert I2C pull-up connect
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Table 2-1. Default Jumper Settings (continued)
Jumper Setting Description
J77 DNI FSYNC loopback for APx connection
J78 DNI SBCLK loopback for APx connection
2.4 I2C Target Address Selection
TAS2574EVM has DIP switches S2 and S3 for setting the I2C target address for each channel individually as per
the table provided in the silk screen of the PCB. Make sure both the devices have different target address.
Figure 2-7. DIP Switch S2-S3 for I2C Address Selection
2.5 IOVDD and AVDD Power Supply Options on EVM
TAS2574EVM daughter card provide multiple flexible options for IOVDD_BUFF, IOVDD and AVDD power
supplies. There are options to select between internal or external voltage sources for each of these supplies
individually.
IOVDD_BUFF is 1.8V power supply, which is used for the buffers and voltage translators.
IOVDD is the input/output power supply for TAS2574 device, which can be either 1.2V or 1.8V.
AVDD is the analog power supply for TAS2574 device, which is 1.8V fixed. If using IOVDD_MB from AC-MB as
1.2V, then make sure to select AVDD source to be either external or +1.8V_LDO.
Figure 6-1shows the default jumper setting for IOVDD_BUFF, IOVDD and AVDD. By default, 1.8V coming from
the AC-MB motherboard (IOVDD_MB) has been selected for IOVDD_BUFF, IOVDD and AVDD with the help of
jumper J9, J5 and J11.
Figure 2-8. Default Jumper Setting for IOVDD_BUFF, IOVDD and AVDD
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There are 1.8V and 3.3V LDOs included in the EVM. These LDOs are powered from the supply connected to
J43, or these can be supplied either from 5 V rail coming from AC-MB, depending on the configuration of jumper
J45.
2.6 VBAT Power Supply for TAS2574 on EVM
By default, the barrel jack connector J43 is used to power VBAT on both TAS2574 channels. Supply 2.4V-5.5V
on this connector.
Alternatively, independent connectors can be used for the external VBAT supply for both the channels –
VBAT1_IN and VBAT2_IN. Jumpers J39 and J46 must be open to disconnect VBAT to VBAT1_IN form J43
input, and similarly J41 and J49 must be open to disconnect VBAT to VBAT2_IN from J43 input.
For channel-1, external VBAT1_IN can be connected between connectors J30 (or J72) and J31 (or J73) as
shown in Figure 7-1.
For channel-2, external VBAT2_IN can be connected between connectors J55 (or J58) and J3 (or J59) as shown
in Figure 7-1.
Channel-1
VBAT1_IN
Channel-2
VBAT2_IN
Channel-1&2
VBAT_IN
Figure 2-9. VBAT Connector for Channel-1 and Channel-2
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2.6.1 VBAT 2S EVM Hardware Configuration
This section shows how to set the EVM jumpers in order to evaluate TAS2574EVM in a 2 S battery application
for VBAT as depicted in Figure 1-2.
In this case, VBAT pin C1 must still be connected to a power supply range from 3 V up to 5 V, while VBAT_SNS
and the boost inductor can be connected to a higher 2 S supply range from 4.5V up to 9 V.
• VBAT pin C1 connection can be connected to USB-5V by changing J56 position to 2-3 instead of 1-2.
• VBAT_SNS pin C4 connection can be modified using J28, this connection is optional.
• 2 S VBAT supply is directly available at J30 (or J72) and J31 (or J73) for channel-1 and J55 (or J58) and
J3 (or J59) for channel-2. If using J43 to supply 2 S battery voltage, then make sure to change J45 to use
+5V_MB instead.
2.6.2 VBAT 3S EVM Hardware Configuration
This section shows how to set the EVM jumpers in order to evaluate TAS2574EVM in a 3 S battery application
for VBAT as depicted in Figure 1-3.
VBAT pin C1 must still be connected to a power supply range from 3 V up to 5 V. VBAT_SNS cannot be used
so VBAT_SNS must be shorted to GND. The internal boost is not used, so the SW pins are left floating and the
inductor can be removed from the circuit.
3 S battery supply range from VBAT pin C1 level up to 14 V is directly connected to PVDD node, the decoupling
capacitors and GREG capacitor are still required.
• VBAT pin C1 connection can be connected to USB-5V by changing J56 position to 2-3 instead of 1-2.
• VBAT_SNS pin C4 connection must be left as default with J28 shorted across pins 2-3.
• 3 S VBAT supply must be connected to J1 for channel-1 and J12 for channel-2, short the jumpers across J29
and J32.
2.7 1-Channel Configuration
When only one of the amplifiers on the TAS2574EVM is required, the other device can be completely isolated
from the circuit. This section includes instructions on how to disconnect U2, however the same procedure can be
applied to disconnect U1.
• The block of jumpers from J98 through J33 must be disconnected, as well as J57 and J52 in the same row.
This removes all digital signals and VBAT supply as well.
• J34 and J35 to the left of U2 must be disconnected as well. This removes IOVDD and AVDD supplies.
• J41 and J49 must be disconnected as well. This removes VBAT connection from J43 to the boost inductor.
2.8 4-Channel Configuration
Two dual-mono EVMs can be interconnected using J75 and J76 headers, mounting one EVM on top of another.
This enables the evaluation of a total of 4 audio channels.
When 2 EVMs are interconnected, the following jumper configuration must be considered:
• Short jumper J51 on one of the EVMs, this jumper is open by default.
• Open jumpers J19 and J20 on both EVMs, these jumpers are shorted by default.
In addition to the jumper configurations, make sure each amplifier is set for a different I2C address using S2 and
S3 on each EVM.
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Figure 2-10. 4-Channel EVM Interconnection
2.9 Speaker Outputs
Since TAS2574EVM is a dual-mono EVM, each channel has a speaker output connector.
SPK1_P and SPK1_N are the outputs for channel-1 device, whereas SPK2_P and SPK2_N are the outputs
for channel-2. Multiple type of connectors have been provided like horizontal banana barrel connectors, vertical
banana sockets, screw terminal connector and pin headers to be able to connect speaker or dummy load with
fly-wires or male banana connectors. These can also be used to connect into an audio analyzer analog input
cable for performance measurements.
Channel-1 output connectors as shown in Figure 8-1:
• J22 (SPK1_P) and J24 (SPK1_N)
• J21 (SPK1_P) and J26 (SPK1_N)
• J23: Pin-2 (SPK1_P) and Pin-1 (SPK1_N)
• TP-16 (SPK1_P) and TP-18 (SPK1_N)
Channel-2 output connectors as shown in Figure 8-1:
• J47 (SPK2_P) and J54 (SPK2_N)
• J25 (SPK2_P) and J27 (SPK2_N)
• J48: Pin-2 (SPK2_P) and Pin-1 (SPK2_N)
• TP-42 (SPK2_P) and TP-44 (SPK2_N)
Channel-1 Output
SPK1_P & SPK1_N
Channel-2 Output
SPK2_P & SPK2_N
Figure 2-11. Speaker Output Connector for Channel-1 and Channel-2
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2.10 4-Wire Measurement of Load
TAS2574EVM has been design such that the dummy load or speaker load connected to the device can be
measured very accurately directly from the device pin including board parasitic and connector contact resistance
using 4-wire method in digital multimeter. Pin header have been provided to be able to connect digital multimeter
in 4-wire mode as shown below Figure 12-1.
For channel-1: Connect HI of DMM to pin-1 and HI_SNS of DMM to pin-2 of TP15 test point.
Connect LO of DMM to pin-2 and LO_SNS of DMM to pin-1 of TP17 test point.
For channel-2: Connect HI of DMM to pin-1 and HI_SNS of DMM to pin-2 of TP41 test point.
Connect LO of DMM to pin-2 and LO_SNS of DMM to pin-1 of TP43 test point.
Figure 2-12. Load DC Resistance Measurement in 4-Wire Mode using Digital Multimeter
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3 Software
3.1 PurePath Console 3 Quick Start Up
PurePath Console 3 configuration tool can be used to interface with TAS2574 using the onboard controller,
which in turn sends I2C commands to setup the required register settings.
When PPC3 is executed for the first time, there are no plug-ins included. The user must click on the Sign In
either from the button at the top-right corner or from the EVM Apps section. A new window requests the user
credentials, input the same myTI account used to request access to PPC3. Once logged in, the requested
device applications are available for download and install.
Once the 257x EVM app has been installed, click on the block with the name to open the GUI. Before
proceeding, connect and power up VBAT to J43 and connect the EVM to a host PC using the USB connector on
the AC-MB.
Figure 3-1. 257x EVM App Main Panel
Once the board is powered and connected to USB, and the PPC3 plug-in is running, the PC automatically
recognizes the device (TAS2574). PPC3 detect as well as the number of channels, depending on how many of
these are being powered and present on the I2C bus.
To initialize the device registers, click on the Device Control tile, and then Apply at the Channel Grouping
window.
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Channel Grouping allows the user to define groups of devices so that a different configuration can be used for
each group. By default, both devices on the EVM are assigned to the same group, to change one of these to a
new group, the device must be deleted from the original group first, and then added to a different group using the
"+" symbol.
Figure 3-2. Channel Grouping
After a few seconds, the devices are initialized and muted. Click on the Power Up button at the top-right corner.
Now, the devices are completely configured and unmuted, ready to play audio.
Figure 3-3. Device Control Panel
3.2 PPC3 - 257x EVM Feature Description
3.2.1 Limiter and Brown-Out Protection
TAS2574 features battery tracking brown-out and limiter features. Each of these features can be configured in
detail as listed below:
Brown-out protection:
• This feature is enabled by default to start attenuation when VBAT drops below 2.9V. An additional threshold
for BOP shutdown can be enabled as well.
• The BOP threshold is the VBAT voltage at which the amplifier starts applying attenuation to the output signal.
• Max attenuation is how much the amplifier reduces the playback signal then BOP is active; this limit goes
from 1 dB down to 16.5dB in 0.5dB steps.
• Attack, Hold, and Release are the timing parameters for the BOP gain controller.
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Limiter:
• This feature is disabled by default. This can be considered an extension of the BOP where gain can be
adjusted dynamically depending on the VBAT level so that output voltage stays within a specified limit.
• Threshold parameter sets Vout-peak limit region. If both min and max settings for this threshold are set to the
same value, then the threshold parameter becomes a hard limiter instead of a dynamic gain controller.
• Inflection point sets the VBAT voltage at which the limiter reaches the maximum threshold.
• Attack, Hold, and Slope parameters set the dynamic gain controller timing settings.
Figure 3-4. Limiter PPC3 Configuration
Figure 3-5. Brown-Out Protection PPC3 Configuration
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3.2.2 Playback and PCM Configuration
Playback and PCM panels provide configuration for the digital input to analog output signal path.
• Volume Control is the gain on the digital domain which goes from -110dB up to 6 dB.
• Ramp Rate is how the gain ramps up/down when going in and out of mute, or when gain is adjusted.
• By default Sample Rate and SBCLK to FS Ratio are set to automatically detect the input clock frequencies,
and adjust the internal clock tree settings based on that. If manual configuration is desired, the checkbox can
be disabled, and the USB Audio Settings can be overridden by clicking on the gear icon on the top-right, then
click to disable the USB settings.
• DC blocker is enabled by default but can be disabled for the Playback (output) path. Both Playback and
Feedback path High-Pass Filter cutoff frequencies can be adjusted manually using the slider or typing a new
value in the text box.
Figure 3-6. Playback and PCM PPC3 Configuration
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3.2.3 TDM Receiver and Transmitter PPC3 Configuration
TDM panel includes all the configuration related to the I2S/TDM audio interface. There is a dedicated tab for
Receiver (SDIN) and Transmitter (SDOUT). Default settings match with USB controller configuration, however
these can be overridden similarly as explained for the previous section.
Receiver configuration can be used to modify the digital audio format in terms of Edge Polarity, Justification,
Frame Start Polarity, Offset Bits, Word Length and Slot Length. In addition to that, the input data can be
arranged from multiple slots or even select a couple slots to result in a mono-mix playback.
Figure 3-7. TDM Receiver PPC3 Configuration
Transmitter configuration provides similar settings for SDOUT timing. Similarly, the output data slots can
be arranged based on the application requirements. Take into consideration that SDOUT slots are always
considered as 8-bit, so for 16-bit data length 2 slots must be used, and for 32bit data length 4 slots are required.
Figure 3-8. TDM Transmitter PCM PPC3 Configuration
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3.2.4 Miscellaneous and IRQZ Configuration
The miscellaneous section can be used to change different portions of the digital interface pins of the TAS2574.
The over temperature, over current and internal clock error can be configured to latch or retry after a wait time,
which is also configurable as 1.5 seconds or 100 milliseconds.
The output of the amplfiier can be set to Hi-Z during shutdown, either due to error interrupt or manual shutdown.
There are internal pull-up resistors that can be enabled and disabled individually at the digital pins such as
SBCLK, FSYNC, SDIN, SDZ, AD0 and AD1.
Figure 3-9. Miscellaneous PPC3 Configuration
IRQZ section includes all the configurations related to the digital notification of error and interrupts internal to the
device.
IRQZ pin can be configured to assert when any live or latched interrupt triggers. The pin can be configured to
assert and de-assert automatically once every live interrupt or the pin can also keep pulsing every 4 ms once a
latched interrupt is triggered.
By default IRQZ pin is an open drain output, however an internal pull-up can be enabled as well. Each of the
internal interrupts can be masked or un-masked to trigger the IRQZ pin.
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Figure 3-10. IRQZ PPC3 Configuration
3.2.5 Tone Generator and Ultrasonic Chirp Generator
TAS2574 features internal tone generator that can be used independently from the digital audio playback. This
sine wave generator can be used in the audible frequency band, or for ultrasonic applications as well. However,
only one of these cases can be used at a time.
The tone generator is a simple tool that can be used to generate sine waves from 16 Hz up to 20 kHz, which
amplitude is configured from -105dB up to 0 dB. There is an optional ramp effect that goes from 0 to 1 second in
10 millisecond steps.
The ultrasonic chirp generator can be used to play a pulsing sweep tone for sine waves with frequencies higher
than 20 kHz. The frequency sweep is set by a start frequency and a bandwidth. The frequency change between
each sweep step is defined from 100 Hz up to 2 kHz. The amplitude of the chirp can be configured from -80dB
and up to -6dB. There is also an optional ramp effect before and after the chirp that goes up to 1 second in
10 millisecond steps. And finally, an Off period between chirps can be configured from 0 to 2 seconds in 10
millisecond steps as well.
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TAS2574 Evaluation Module 19
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Figure 3-11. Tone and Ultrasonic Chirp Generator PPC3 Configuration
3.2.6 AVDD Bridge, Music Efficiency and Noise Gate
TAS2574 includes several features to improve the amplifier efficiency and prolong the play time in battery
powered applications. All these features can be configured individually, and even disable if not required for the
application
The noise gate feature can be used to shutdown the amplifier dynamically based on the input audio content
amplitude. The threshold can be configured from -120dBFS up to -85dBFS and the hysteresis time from 10
milliseconds up to 1000 milliseconds.
Music efficiency mode enables very low consumption at low output power levels, the threshold is set to 50mW by
default and the hysteresis timer can be configured up to 500 milliseconds.
AVDD bridge reduces the power consumption by driving the amplifier output from the AVDD 1.8V power supply,
instead of the higher voltage from VBAT, when the output signal is below a set threshold up to 110 milliwatts. The
hysteresis timer can be set from 0.1 millisecond up to 50 milliseconds.
In all cases, shorter hysteresis time improves efficiency with a tradeoff in potential audio artifacts due to the fast
switching between the different playback/power modes.
Figure 3-12. AVDD Bridge, Music Efficiency and Noise Gate PPC3 Configuration
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20 TAS2574 Evaluation Module SLAU896 – JULY 2023
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