UC1901: Alternative for new designs

Ayubu Mbogela

Part Number: UC1901
Other Parts Discussed in Thread: UCC2808A-1, TL494

Tool/software:

Hello Team,

I am considering U1901L for my new power system design for space application, to be used in feedback signal isolation. The TI website indicates zero inventory (it has been a couple of weeks and I opted to be notified when stock is available) and does not recommend UC1901 for new designs. However, the recommended alternative by TI, UCC2808A, does not generate an AC output waveform that can be coupled with a transformer for magnetic isolation. It is simply a PWM generator, from what I have gathered from its datasheet. I have looked at the option of offsetting a PWM signal so that I get an AC signal but I have opted to not go that route. I would simply want to use something similar to UC1901 that produces an AC waveform modulated by a DC signal that I want to get across an isolation boundary.

Is there an alternative part to UC1901, considering my requirements?

1 month ago

0 Hong Huang 1 month ago

TI__Guru 54055 points

Hi,

What AC output you want to have and which pins of UC1901 you use to get the AC output?

0 Ayubu Mbogela 1 month ago in reply to Hong Huang

Prodigy 10 points

Hi,

Output on pin 'DRIVERA' and pin 'DRIVERB'. According to the datasheet it is a square AC waveform with frequency and amplitude set through design (frequency set using 'RT' and 'CT' pins; amplitude set using 'VIN' pin)

0 Hong Huang 1 month ago in reply to Ayubu Mbogela

TI__Guru 54055 points

Hi,

It looks UCC2808A-1, or -2 OUTA and OUTB should produce similar - what difference do you see from UCC2808A-1, or -2 that cannot meet your requirements?

TL494 maybe another device can be considered.

0 Ayubu Mbogela 1 month ago in reply to Hong Huang

Prodigy 10 points

The main difference between U1901 and UCC2808A is: UC1901 generates an AC waveform out of pin 'DRIVERA' and pin 'DRIVERB'. This AC waveform can be interfaced to a transformer to achieve magnetic isolation. On the other hand, UCC2808A generates a DC PWM signal out of pin 'OUTA' and pin 'OUTB'. This DC signal cannot be interfaced to a transformer.

0 Hong Huang 1 month ago in reply to Ayubu Mbogela

TI__Guru 54055 points

Hi,

What about TL494?

Is it ok to add external MOSFETs to connect the transformer if using ucc2808A?

0 Ayubu Mbogela 1 month ago in reply to Hong Huang

Prodigy 10 points

TL494 is similar to UCC2808A in that it produces an output with a DC average.

Could you please elaborate on adding external MOSFETs to connect the transformer if using ucc2808A?

0 Hong Huang 1 month ago in reply to Ayubu Mbogela

TI__Guru 54055 points

Hi,

See the below.

Amplifiers

Amplifiers forum

UC1901: Alternative for new designs