Hi,
I've been working with changing design requirements for an upcoming micro. There was need for an SPI eeprom of 64KB, that has since changed to 1MB+. The space on the pcb is really only going to allow for an soic-8 or smaller chip. I was going to use a 5V tolerant microchip part but they top out at 1Mbit. I've found an STM part that will work but its 3V max.
The 3V output from the rom is not enough to trigger the pic's input as High.
I've secured enough room for the chip, an sot-23 regulator and some level shifting.
I've got two options, one is to use 3 small sot-23 mosfets that will each need a resistor to do the level shifting, the other option is to use an integrated level shifter.
I'm slightly concerned of the transition time using mosfets as the source resistor may cause problems at 10Mhz (or leak too much current at low level). Likewise a concern with the integrated translator is that I don't have a level shifter picked out and haven't so far seen a 3bit or 4bit that is small enough.
Recommendations ? Thanks
I've been working with changing design requirements for an upcoming micro. There was need for an SPI eeprom of 64KB, that has since changed to 1MB+. The space on the pcb is really only going to allow for an soic-8 or smaller chip. I was going to use a 5V tolerant microchip part but they top out at 1Mbit. I've found an STM part that will work but its 3V max.
The 3V output from the rom is not enough to trigger the pic's input as High.
I've secured enough room for the chip, an sot-23 regulator and some level shifting.
I've got two options, one is to use 3 small sot-23 mosfets that will each need a resistor to do the level shifting, the other option is to use an integrated level shifter.
I'm slightly concerned of the transition time using mosfets as the source resistor may cause problems at 10Mhz (or leak too much current at low level). Likewise a concern with the integrated translator is that I don't have a level shifter picked out and haven't so far seen a 3bit or 4bit that is small enough.
Recommendations ? Thanks