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Originally Posted by rds /img/forum/go_quote.gif
You should make sure you read things carefully before you start giving advice.
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we all could use some of that, right?
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I think TI would beg to differ. here is exactly what they said:
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Originally Posted by TI AN: sbva013a.pdf
The DCP01B, DCV01, and DCP02 are three families of miniature DC/DC converters providing an isolated unregulated voltage output. All are fabricated using a CMOS/DMOS process with the DCP01B replacing the familiar
DCP01 family that was fabricated from a bipolar process. The DCP02 is essentially an extension of the DCP01B family providing a higher power output with a significantly improved load regulation, and the DCV01 is tested to a
higher isolation voltage.
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so is that enough to establish the fact that dcp01 (no
B) is a bipolar process?
As to dcp02/dcv01, well, here comes from their datasheet:
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Originally Posted by TI datasheet for DCV
The circuit design utilizes an advanced BiCMOS/DMOS process.
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Originally Posted by TI datasheet for DCP02
The circuit design uses SYNC pins together, taking care to minimize the an advanced BiCMOS/DMOS process.
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I would take a wild guess that
Bi in BiCMOS means
Bipolar?
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But compare the performance curves of the dcp and dcv. The output ripple for dcp at the 140mA max we'll be using is about 20mV with a 1uF cermanic. Now for the dcv using 70mA per rail there's about 35mV ripple with a 1uF cap. |
here is a comparison of two particular chips, dcp020505 vs. dcv010505, straight out of TI's datasheets for those respective chips.
at 50% load, for 1uf cap, dcp02 has a ripple of <25mv, and dcv01 has a ripple of ~18mv (my estimate). so ~18mv is quite comparable to <25mv, right?
at 100% load, for 1uf cap, dcp02 has a ripple of <50mv and dcv01 has a ripple of ~50mv. so ~50mv is quite comparable to <50mv, right?
so how do we recouncile your numbers to TI's?
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The dcp02 ... has better load regulation. |
let's talk about regulation.
look at the 2nd attachment. from 20% load to 100% load, dcp02 has a regulation of 6% (106% to 100%), and dcv01 has a regulation of 8% (108% to 100%). better? yes. material? probably not.
and if you look a few pages earlier, both chips are quoted to have 1% regulation (constant Io).
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The dcv is not the new dcp02. |
nobody said it is. better reading would have helped here.
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In fact, there's no reason for us to use it as we don't need huge isolation voltage. |
nor the higher wattage? nor the 2% better regulation? ...
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I don't mean to sound like a jerk, but it is kind of annoying when people jump in and start saying this stuff in very matter of fact way when they don't have their facts straight. |
agreed. having your facts straight does help.