The TPS7A47 Eval Board
Just got in the evaluation board for the new TI ultra low noise regulator, the TI TPS7A4700
I would consider this a real bargain for audio diy at $20 including shipping. In came in a huge box and it was shipped Federal Express in an even bigger box. I think TI should cut the shipping cost and pass the savings to the customers. But I suppose it is more important for business customers to get it on time and without damage than saving a few bucks.
Here are some photos
Here are the packaging and shipping boxes. I did a quick check on on the FedEx site for shipping cost for a FedEx box: $17.67. You are basically getting the board for free!
Data sheet of device: [link]
Data sheet of Eval Board: [link]
OUTPUT VOLTAGE SELECTION
Output voltage selection is done by shorting jumpers. The resultant output corresponds to the addition of the internal voltage reference (1.4 v) and the voltages indicated by the jumpers.
The board clearly labels how to select the output voltage:
Internally, the jumpers just change the value of the voltage divider resistor as shown by the diagram below. Certainly much cheaper than implementing a potentiometer.
NOISE
The TI “7A47″ has half the RMS noise as the ADP-150 at 4.17 uV RMS. (The dotted blue line is the noise plot for a 5V LT1763. Compare that to the noise plot for Vout=5v -blue solid line)
Compare the above noise plot with that of the ADP-150 shown below
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TI’s overkill shipping has always bothered me, even from a business perspective. They could at least give us lower cost options…
Question for you: Does the EN pin completely shut off the output MOSFET? I’ve seen a few TI parts leak output when ‘disabled’.
Hello John,
Thanks for stopping by.
Have not tested the eval board, but will keep your question in mind when I do. Ti’s shipping practice is indeed very wasteful, but maybe this is the most reliable way to get stuff to their business customer (e.g. large boxes are much harder for “loose”). But I agree with you: give an option to the customer.
Hey, how about putting together an ESS9023 kit with this regulator and only I2S input and optional local clock?
Let me start by saying that I’m a software guy who’s only very recently started learning about hardware – mainly because I’ve decided to try building a Buffalo III. So my apologies if this is a stupid question, but can this eval board be used in place of the Placid regulators sold by TPA?
Partly. The Placid include the bridge and filter capacitors so you only need to provide a transformer. These are just voltage regulators. You will need to build the DC conversion part consisting of a bridge rectifier and filter capacitors. Then you can apply the DC to the regulators. Since you are new I would recommend that you use the Placid supplies. In addition, the Placids are of “shunt” design whereas this regulator is of “series” design. Shunt regulators respond better to varying demands of power which the DAC would do
We can read in all descriptions of this regulator : “For systems where both positive and negative voltage rails are required, the TPS7A4700 can be used together with TI’s -36V/-1A TPS7A3301 LDO linear regulator.” But in fact, TPS7A3301 is also a regulator which operates with negative voltage, so can we use negative voltage as input of the TPS7A4700?
Hi,
Recently bought this evaluation kit but it’s not doing what is supossed to do.
Reference voltage in mi kit is not giving me 1.4v. It’s giving me 3.03v… Why?
And if I connect the jumpers on the 100mv, 200mv and 1.6v nothing change, just with the others ones.
Do you know why? I think my evaluation kit is factory defective
Possible there are some shorts. on the adjustment pins. You can check to see if this is the case.