SN74LVC1T45: Technical Inquiry about SN74LVC1T45

? ??

Part Number: SN74LVC1T45

Tool/software:

Hi,

We design a level-shifting circuit using the SN74LVC1T45 to translate 3.3V level signals to 5V level signals from PORT_A to PORT_B as Figure1.The TRIGGER_CTL is 3.3V.The high-level voltage of PORT_B can only reach 4.7V but not 5V.Why does the high-level voltage of PORT_B only reach 4.7V instead of the expected 5V?

Figure 1

4 months ago

0 Clemens Ladisch 4 months ago

Guru 316690 points

The output resistance of an LVC output is about 12 Ω. So I'd guess you have a load of about 25 mA connected to PORT_B. (If not, check for shorts due to soldering errors.)

0 ? ?? 4 months ago

Prodigy 105 points

The output is not connected to any load, and the soldering has been inspected with no issues detected. After replacing a chip, the output of PORT_B still remains at 4.7V.What could be the reason?

0 Clemens Ladisch 4 months ago in reply to ? ??

Guru 316690 points

Check the VCCB pin. If the voltage is different from that at the B pin, then a current must flow out of the B pin.

0 ? ?? 4 months ago in reply to Clemens Ladisch

Prodigy 105 points

Hi,

This is the silkscreen on the chip.Is this chip the SN74LVC1T45?

+1 Clemens Ladisch 4 months ago in reply to ? ??

Guru 316690 points

Yes.

Interface

Interface forum

SN74LVC1T45: Technical Inquiry about SN74LVC1T45