Hello,
What is the output resistance (high and low) of the PNP/NPN ‘totem pole’ driver stage in the attached schematic?
I take it that “R(out) high” is RB/hfe = 1000/200 = 5 ohms?
The problem is that the datasheets only quote hfe at 25degC and our ambient temperature is 170degC, how will this affect the hfe value?
FMMT619 NPN datasheet
**broken link removed**
FMMT720 PNP datasheet
**broken link removed**
What is the output resistance (high and low) of the PNP/NPN ‘totem pole’ driver stage in the attached schematic?
I take it that “R(out) high” is RB/hfe = 1000/200 = 5 ohms?
The problem is that the datasheets only quote hfe at 25degC and our ambient temperature is 170degC, how will this affect the hfe value?
FMMT619 NPN datasheet
**broken link removed**
FMMT720 PNP datasheet
**broken link removed**