Precision DAC sample rate

Question

Hello support team, 
 I am looking for the 12 Bit DAC , with output voltage requirement : 0 to 10 V, when I go through the datasheets for the 12 bit Precision DAC, I have not found sample rate written in the datasheet. 
 My sample rate requirement is 1 MSPS or better 
 Please suggest where I an find sample rate in precision DAC list? 
 Awaited your positive response.

EZAutoReply · Accepted Answer

Hi, 
 At the moment, I couldn't find a specific app note for this. You want to have an output update rate of 1MSPS. This means you need 1us for the output to settle to 12bit accuracy. And you need to choose a DAC that can have an interface update rate that is much lower than 1us. so that you could take the time while the output is settling, to send another command for the next output value. The image below should support this 
 
 Dac output settling time is measured from the time when the digital command has finished sending to the time the output settles to the set value given a certain %band. 
 Output capacitance would greatly affect this settling time. The datasheet settling time spec for LTC2664 is given for 100pF load. 
 The settling time is also greatly dependent on the output amplifier used. On some devices, the output amplifier is integrated. But if you want a faster settling time at your given voltage step or load capacitance you could look at DACs with no output amplifier integrated. 
 I'd suggest is the AD5760 (Rev. F) (analog.com) in this case, has an output settling time of 2.5us at 10V step. Using the ADA4898-1 Datasheet and Product Info | Analog Devices amplifier. Again, with a lower step or 12-bit accuracy should be fine. 
 Or the AD5791 (Rev. F) (analog.com) , which has a 1us settling at 10V step using the AD845 Precision, 16 MHz CBFET Op Amp Data Sheet (REV. E) (analog.com) 
 Best regards, 
 Ian)

EZAutoReply · Answer

Hi, 
 It would be better if we refer to the update rate of the DAC output in MUPS, updates per second. MSPS is samples per second and is used in ADCs for sampling rate. 
 It would be a different case if you want 1MUPS for multiple channels. you'd need N times faster update rate than the single-channel update rate, with N being the number of channels you want. ie. to be able to output 1MUPS on all 4 channels, you'd need a DAC with at least 4x MUPS update rate. 
 At best, you could achieve a 1MUPS output on a single channel on the AD5724R. ~0.25MUPS if you want 4 channels. 
 The LTC2664 on the other hand could give 2MUPS on a single channel, and 0.5MUPS for 4. 
 You could also look at a parallel interface DAC, like the AD5725 (Rev. C) (analog.com) , has a 10us settling time for a 10V step, and around 50MUPS interface rate. 
 Or again, go back to considering the Fast Precision DACs AD3542R Datasheet and Product Info | Analog Devices , dual-channel DAC, 16MUPS single channel rate. 
 Best regards, 
 Ian

EZAutoReply · Answer

Hello Maitry 
 Apologies for the late response, The AD5696 is a lot slower as it uses I2C protocol, able to operate only at 400kHz max. The single channel update rate is around ~14 KUPS. 
 For your application, our Fast Precision D/A Converters are the ones that could fit. 
 Best regards, 
 ~ian

EZAutoReply · Answer

Hi, 
 DACs under the "precision" category normally don't have a sample rate directly provided in the datasheet. It can be computed using the settling time spec, but since the specification is focused on precision, you might get a not-so-high, out-of-the-box sampling rate. 
 My suggestion is to look into our new Fast Precision DACs, AD3551R Datasheet and Product Info | Analog Devices works for 0to10V and could support upt o33MSPS update rate. 
 See this table for other available fast precision DACs. Selection Table for Fast Precision D/A Converters | Parametric Search | Analog Devices 
 ~ian

EZAutoReply · Answer

DId a quick search, you could check out the LTC2664 Datasheet and Product Info | Analog Devices . Has 50MHz Serial interface clock. and settling time of 4.5us with a 5V step at +/-1LSB accuracy. a smaller voltage transition should be enough for 1MSPS. The settling time would also greatly vary depending on the capacitance of your intended output load. So actual tests would guarantee best results.

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Precision DAC sample rate