Amanerotechnologies

COMBO768 USB TO I2S DSD CONVERTER
Rev A. Datasheet
version 31/07/2024
Amanero SRL All rights reserved

FEATURES•CoreARM® Cortex®-M7 IMXRT1011
Arm and Cortex are registered trademarks of Arm Limited•

OSCILLATORSXO 49.1520 MHz Low phase noise
XO 45.1584 MHz Low phase noise
Crystal 24 MHz•USB
USB 2.0 High Speed Class 2 compatible
No drivers for Mac OSX® 10.6+
Mac OSX are trademarks of Apple Inc

No drivers for Linux UAC2 Kernel compliant
No Kernel Drivers for MS Windows®
ASIO® for Windows
ASIO is a registered trademark of Steinberg Media Technologies GmbHWindows is a registered trademarks of Microsoft Corporation

•

AUDIO
PCM sample rates 44.1kHz 48kHz, 88,2kHz,96kHz,192kHz,352.8kHz, 384kHz,705,6kHz,768kHz,1411,2kHz,1536kHz(TDM2) I2S output
DoP sample rates DSD64 - DSD512
PCM token FA05
Native DSD Linux/Windows DSD64 - DSD1024
Native DSD on Windows requires ASIO driver•OUTPUTLVCMOS33
Powered by USB 5V bus or from external 3.3V power supply.
Power Consumption is TBD at max speed.
The module mounts an ultra low noise LDO ADP-151-3.3V ADP-151-1.2V•ROHS

DESCRIPTION
The Combo768 is an USB audio device adapter designed for OEM applications. USB PCM audio
data (2 channels) accepted as input are converted into an I2S stream or a native DSD stream.
Supported PCM sampling frequencies range from 44.1kHz to 1536kHz(TDM2). The maximum
sample rate can be limited to 192kHz, 384kHz, or 768kHz.
The DSD format is decoded both in DoP format (FA05 token) and in native format. In DoP
format, the maximum sample rate is DSD512, while in native DSD format, the maximum
sample rate is DSD1024.

Amanero

COMBO768 USB TO I2S DSD CONVERTER
Rev A. Datasheet

technologies

version 31/07/2024
Amanero SRL All rights reserved

On Windows, no kernel mode drivers are required, as system USB drivers are used, ensuring
they are always up to date. Additionally, a ASIO driver is provided to support native DSD from
DSD64 to DSD1024.
On Linux, with a kernel supporting native DSD, you can achieve up to DSD1024.
Native DSD support in Linux is constrained by the USB VID/PID. The Combo768 base board
uses VID=0x16d0 and PID=0x0A23, values already included in many Linux distributions asenabled for native DSD.
Audio Clocks are generated by two low phase noise oscillators at 45.1584MHz/49.152MHz.
The CPU is a Cortex-M7 NXP IMXRT1011 and the external flash is W25Q32. The power supply
requires 3.3V and 1.2V.
An incoming DSD stream is indicated by an asserted signal in a specific DSD ON pin of theoutput comb connector and the I2S DATA and I2S FSCLK pins become the DSD Left/Right
output pins.
The module works in Master Mode Only.

Output connector
header 10x2 raw 2.54 pitch
1 Cable Plugged-It's “1” When the usb cable is plugged

2Reserved-3

I2S DATA/DSD1Out

Data stream LVCMOS 3.3V 47ohm

4I2S CLK/DSD CLKOutClock LVCMOS 3.3V 47ohm

5I2S FSCLK/DSD2OutFrame sync LVCMOS 3.3V 47ohm

6MCLKOut

Actual Master Clock 24.576MHz or 22.5792MHz

7DSD ON

Out

This line is “1” when a DSD stream is detected. ( FA05 in the PCM
envelope MSB ) LVCMOS 3.3V

8GND

PowerGround Terminal

9103.3V output(max 50mA)

PowerOutThis output can be used to power an isolator or it can be used todetect when the usb is connected to the PC.

11MUTE

OutThis line is “1” during a sample rate change or when the DSD modeis changing.

12Reserved-

13

GND

PowerGround Terminal

14GND

PowerGround Terminal

15

GND

PowerGround Terminal

16

DSD64_128

Out0=DSD64 1=DSD128 -open drain-

17F0Out

Sample rate indicator see table below

18F1

Out

Sample rate indicator see table below

19F2

Out

Sample rate indicator see table below

20F3Out

Sample rate indicator see table below

Amanero

COMBO768 USB TO I2S DSD CONVERTER
Rev A. Datasheet

technologies

version 31/07/2024
Amanero SRL All rights reserved

Output Connector pinout[11] Mute [12] SDA[13]GND[14]GND[15]GND[16]DSD[1] Plug[3] DATA[4] CLK[5]FSCLK[6] MCLK [7]DSDON[2] SCL[17]F0[18]F1[19]F2[20]F3[8]GND[9]3.3V[10]3.3V

Windows ASIO Drivers can be downloaded on request at support@amanero.com
ELECTRICAL CHARACTERISTICS
ABSOLUTE RATINGS*
Storage Temperature......................................-40°C to + 85°C
Maximum Operating Voltage ............................5.5V USB supply*NOTICE: Stresses beyond those listed under “Absolute MaximumRatings” may cause permanent damage to the device.
This is a stress rating only and functional operation of thedevice at these or other conditions beyond those indicatedin the operational sections of this specification is
not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability

Sample Rate Indicators
DSDOE=0 PCM
0 (F3), 0 (F2), 0(F1), 0(F0) -> 32kHz
0 (F3), 0 (F2), 0(F1), 1(F0) -> 44.1kHz
0 (F3), 0 (F2), 1(F1), 0(F0) -> 48kHz
0 (F3), 0 (F2), 1(F1), 1(F0) -> 88.2kHz
0 (F3), 1 (F2), 0(F1), 0(F0) -> 96kHz
0 (F3), 1 (F2), 0(F1), 1(F0) -> 176.4kHz
0 (F3), 1 (F2), 1(F1), 0(F0) -> 192kHz
0 (F3), 1 (F2), 1(F1), 1(F0) -> 352.8kHz
1 (F3), 0 (F2), 0(F1), 0(F0) -> 384kHz
1 (F3), 0 (F2), 0(F1), 1(F0) →> 705,6kHz
1 (F3), 0 (F2), 1(F1), 0(F0) →> 768kHz
1 (F3), 0 (F2), 0(F1), 1(F0) →> 1411,2kHz
1 (F3), 1 (F2), 0(F1), 0(F0) →> 1536kHzDSDOE=1 DSD
1 (F3), 0(F2), 0(F1), 1(F0) →> DSD64
1 (F3), 0(F2), 1(F1), 0(F0) →> DSD128
1 (F3), 0(F2), 1(F1), 1(F0) →> DSD256
1 (F3), 1(F2), 0(F1), 0(F0) →> DSD512
1 (F3), 1(F2), 0(F1), 1(F0) →> DSD1024

DC Characteristics
VCCIO 3.3V

SymbolParameterMinMax

VOH

High level output voltage

VCCIO – 0.4V ( Ioh=-8mA)-VOL

Low level output voltage_0.4 V ( Iol=8mA )Pdc

Power consumption at32/1536kHz

TBD

Amanero

COMBO768 USB TO I2S DSD CONVERTER
Rev A. Datasheet

technologies

version 31/07/2024
Amanero SRL All rights reserved

Timing Diagrams
I2S Mode

I2S_FSCLKI2S_CLKI2S_DATADSD_OE
MUTE
1234567891011121314151617181920212223242526272829

234567891011121314151617181920212223242526272829

DSD Mode

I2S_FSCLKI2S_CLKI2S_DATADSD_OE
MUTE
1In DSD Mode the I2S_CLK becomes the DSD clock signal, the I2S_Data becomes the output
data line DSD1 (LEFT) and I2S_FSCLK becomes the DSD2 (RIGHT) Line.

Amanerotechnologies

COMBO768 USB TO I2S DSD CONVERTER
Rev A. Datasheet
version 31/07/2024
Amanero SRL All rights reserved

Maintenance and programming
The firmware update is performed through a maintenance program in Windows, which also
allows customization of the Device Name, Manufacturer, and USB VID/PID. The maintenanceprogram automatically handles the reprogramming of the board, and the flash memory iserased via software.

Amanerotechnologies

COMBO768 USB TO I2S DSD CONVERTER
Rev A. Datasheet
version 31/07/2024
Amanero SRL All rights reserved

Evaluation module
When the jumper P1 is soldered, the LDO 3.3V regulator is disabled, and it is possible to supply
external power at 3.3V from the main output connector of the board.
When jumper P3 is closed while powering the board or plugging in the USB cable, it forces the programming
mode. This operation is not required for firmware updates and is only intended in the case of a total reset.
P4 reserved for test
P5 is an auxiliary connector for using the board with specific firmware in TDM mode to have PCM1536 kHz on 2 lines.

NOTICE
This product is ROHS
Amanero SRL reserves the right to make corrections, modifications, enhancements, improvements,and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete.
This is a preliminary datasheet and is not complete.