THS4281EVM: This EVM seems to not have schematic attached.

Fan Yi

Part Number: THS4281EVM
Other Parts Discussed in Thread: THS4281

Unlike other EVM, THS4281 seems to not have schematic attached.

This is too odd that there is no seperate EVM specification document. Instead, only a layout section in the datasheet is provided.

The EVM still lacks schematic and BOM information which usually can be easily found within other device's EVM specification.

By the way, the schematic shown in the first page of THS4281 datasheet looks wrong. The inverting and non-inverting inputs hooking on the sensing resistor's ends should be swapped.

Could you please help clarify these concerns.

Thanks a lot.

over 4 years ago

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi Fan,

if you have a close look at the layout in figure 76 and 79 of datasheet, you will notice that the circuit of EVM is extremely simple. And the datasheet contains enough information to find out what sort of resistances are suited for this circuit. See figure 68 and 69 of datasheet.

No, the schematic on the first page isn't wrong. As no OPAmp can fully swing with the output to the negative supply rail, the output of THS4281 emits VBAT/2 when measuring zero current and the output voltage decreases when the measuring current increases.

Kai

0 Fan Yi over 4 years ago in reply to kai klaas69

Intellectual 280 points

Hi Kai,
Thanks for the response.
We'd like to quickly start to evaluate the chip within our application context that needs minimum change to the original configuration.
Nevertheless, a concrete schematic and BOM will be very helpful, otherwise we have to reverse-engineer the circuit including both circuit structure and component value, let alone the rating in details.
As for the schematic, do you notice the equation Vout=Isense on the output side ?
Could you help derive this equation based on such configuration?
Thanks again.

0 kai klaas69 over 4 years ago in reply to Fan Yi

Guru 140200 points

Hi Fan,

yes, I did notice the eqution "Vout = Isense". But I think it is meant in the way I described, because it's impossible for the THS4281 to emit 0V output voltage for Isense = 0A: