LTC2380-24 and LTC2368-24 Multidevice Synchronization?

Hi malee ,

I'll contact the product owner and get back to you.

Regards,
Jo

Great, thanks!

Hi malee 

May I know your application for the 3 synchronized ADCs?

As of now, please read these pages from respective datasheets.

For LTC2380-24, refer to pages 25-27, (Chain Mode, Multiple Devices)

For LTC2368-24, refer to pages 24-26, (Chain Mode, Multiple Devices)

For your additional reference, you may check this link: Introduction to SPI Interface | Analog Devices

Thank you.

Regards,

Red

Hello,

Application is taking 3 channels of ADC and comparing phase of the input signal.  We require the sampling clocks on the ADCs to be in SYNC down to the individual clock.  Does using the convert pin align the internal sampling clocks of individual ADCs?

Thanks,
Mike

Hello,

Application is taking 3 channels of ADC and comparing phase of the input signal.  We require the sampling clocks on the ADCs to be in SYNC down to the individual clock.  Does using the convert pin align the internal sampling clocks of individual ADCs?

Thanks,
Mike

Hi malee 

Each device has independent sampling clock and conversion time, (tconv). The tconv will also vary for each device, since there is a range for minimum and maximum conversion time (Please check the datasheet). Hence, considering your application, we cannot guarantee that the 3 independent ADCs will convert simultaneously.

Please refer to the Normal Mode, Multiple Devices: page 26 for LTC2380-24 and page 25 for LTC2368-24.

Also take note of these:

1. The conversion is controlled by CNV. A rising edge on CNV will start a conversion and power up the device. Once a conversion has been initiated, it cannot be restarted until the conversion is complete. 

2. Since SDO is shared, the RDL/SDI input of each ADC must be used to allow only one LTC2380-24 or LTC2368-24 to drive SDO at a time to avoid bus conflicts.

3. Both devices have an internal clock that is trimmed to achieve a maximum conversion time.

May I know your other requirements for your project? I can recommend other Analog Devices, which I think more suitable for an application which requires a multiple channel.

Please check these links: 

1. AD7380-4 (Rev. 0) (analog.com): The AD7380-4 is a 16-bit compatible, quad, simultaneous sampling, high speed, successive approximation register (SAR), analog-to-digital converters (ADC) operating from a 3.3 V power supply with throughput rates up to 4 MSPS. The differential analog input accepts a wide common-mode input voltage and is sampled and converted on the falling edge of CS.

2. AD4630-24/AD4632-24 (Rev. B) (analog.com): The AD4630-24/AD4632-24 are two-channel, simultaneous sampling, Easy Drive, 2 MSPS or 500 kSPS successive approximation register (SAR) analog-to-digital converters (ADCs).

3.AD4858 (Rev. 0) (analog.com): The AD4858 is a fully buffered, 8-channel simultaneous sampling, 20-bit, 1 MSPS data acquisition system (DAS) with differential, wide common-mode range inputs.

Thank you.

Kind regards,

Red

Hi Red,

Thank you for the detailed response and suggestions.  I think we are leaning towards using the LTC2500 because of the digital filters and decimation.

Thank you for your time.
Mike

Hi malee 

You are welcome. Good to know that you've already decided which device to be used.

Thanks.

regards,

Red