| ??? 07/04/08 08:36 Read: times |
#156397 - BSS138 Responding to: ???'s previous message |
Michael Karas said:
The BSS138 is barely suitable for this application. When the 1.8V side drives the I/O low the BSS138 will experience a Vgs drive of 1.8V minus the Vol of the driving logic. A look at the BSS138 data sheet will show this is barely inside the spec for the part.
Vol=0.18; I had a look it comes out to be 1.8V-0.18= 1.62 , and the spec for BSS138 says VGSth=1.5max , is this not ok ? , I am little confuse. Erik , I have some constaraints I dont have 1.8VDC other than potential divided. I cant use level shifter as it requires a dedicated 1.8V regulator on the lower side. My module is powered by 3.3V and its pins are 1.8V . -Ap |
| Topic | Author | Date |
| 1.8<-->5V Level | 01/01/70 00:00 | |
| TI and NXP | 01/01/70 00:00 | |
| Any specific part number? | 01/01/70 00:00 | |
| pssibly | 01/01/70 00:00 | |
| Ok but about part | 01/01/70 00:00 | |
| Try digikey | 01/01/70 00:00 | |
| I read about some MOSFETs that switch at <1.5V | 01/01/70 00:00 | |
| why fiddle when there are dedicated chips? | 01/01/70 00:00 | |
| It depends on how many he needs, doesn't it? | 01/01/70 00:00 | |
| not really | 01/01/70 00:00 | |
| and what's price and availability in small quantit | 01/01/70 00:00 | |
| Any discrete solution | 01/01/70 00:00 | |
| a transistor ? | 01/01/70 00:00 | |
| nxp ANSWER | 01/01/70 00:00 | |
| NXP Picogates | 01/01/70 00:00 | |
| I read about some MOSFETs that switch at <1.5V | 01/01/70 00:00 | |
| Schematic here | 01/01/70 00:00 | |
| The BSS138... | 01/01/70 00:00 | |
| another part | 01/01/70 00:00 | |
| Very bad choice | 01/01/70 00:00 | |
| why, OH why ... | 01/01/70 00:00 | |
| 8 lines | 01/01/70 00:00 | |
| I listed 1, 2 and 6 line chips in a former post | 01/01/70 00:00 | |
| why not | 01/01/70 00:00 | |
| ZXM61N02 | 01/01/70 00:00 | |
BSS138 | 01/01/70 00:00 |