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About the operation of the STG3157

Kimi_NAKAMUL
Visitor

”Switch S1 is ON (connected to common port D) when the IN input is held high, and
OFF (a high impedance state exists between the two ports) when IN is held low.
Switch S2 is ON (connected to common port D) when the IN input is held low and
OFF (a high impedance state exists between the two ports) when IN is held high.”
Table 1. Truth table

These says that "IN=VCC -> S1=ON" and "IN=GND -> S2=ON".

Figure 3. On-resistance
Figure 4. Bandwidth

These seems that "IN=VCC -> S2=ON" and "IN=GND -> S1=ON".

Could you please tell me which of the above is correct?
I haven't received the actual item yet.

 

1 REPLY 1
Peter BENSCH
ST Employee

Welcome @Kimi_NAKAMUL, to the community!

I am extremely sorry that there are still some inconsistencies in the data sheet. Although the device was introduced in 2002, nobody had apparently noticed this. However, it is pin- and function-compatible with the 74LVC3157, even if individual pins are labelled differently here.

The information in the logic table table 1 is correct, i.e. at IN (pin 6) = high S1 (pin 1) is connected low impedance to D (pin 4). The information in the test circuits is therefore somewhat mixed up and incorrect.

Thank you very much for bringing this to our attention!

Regards
/Peter

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