C
[email protected]
- Jan 1, 1970
- 0
Hi all,
The only missing link in a design I'm doing is a swith that must be
able to operate at very low voltages (1V or less if possible), have
minimal losses, available through mouser/digikey/etc, and be
through-hole (TO-220, say) for breadboard prototyping. I've been out of
the field for some time so I don't know what's available. Here are the
specs:
rON max @ 500mA : 100mOhms
Vgs(th) : as small as possible, less than 1V
Vgs(ON): less than 1V
Imax, power, etc : should be able to handle 500mA when ON.
frequency is irrelevant. The switch is going to be turned on or off
every few seconds at the fastest. Relays don't cut it because the
circuit is going to be constantly shaking!
Bipolar darlingtons (I would need them because I also don't have much
power available to turn the switch ON/OFF) seem to be out of the
question since their Vce(sat) is 1V or more, translating to an rON of
about 2 ohms. Their Vbe(on) is also not that great.
I found this Vishay P-channel MOSFET (SUP/SUB15P01-52) which comes
close, and that I *could* use at the cost of 2 more transistors and
resistors in the design. Unfortunately there seems to be no N-channel
equivalents. From what I see there are no IGBTs that cut it due to
Vce(sat).
Strictly speaking the switch should be 'on' by default, but I couldn't
find any depletion mode MOSFETs that would satisfy the Ron and
through-hole specs, that's why I am look for very low threshold
enhancement mode transistors.
Are the specs hopeless, or does anybody know of something useable?
Best,
- Cesar
The only missing link in a design I'm doing is a swith that must be
able to operate at very low voltages (1V or less if possible), have
minimal losses, available through mouser/digikey/etc, and be
through-hole (TO-220, say) for breadboard prototyping. I've been out of
the field for some time so I don't know what's available. Here are the
specs:
rON max @ 500mA : 100mOhms
Vgs(th) : as small as possible, less than 1V
Vgs(ON): less than 1V
Imax, power, etc : should be able to handle 500mA when ON.
frequency is irrelevant. The switch is going to be turned on or off
every few seconds at the fastest. Relays don't cut it because the
circuit is going to be constantly shaking!
Bipolar darlingtons (I would need them because I also don't have much
power available to turn the switch ON/OFF) seem to be out of the
question since their Vce(sat) is 1V or more, translating to an rON of
about 2 ohms. Their Vbe(on) is also not that great.
I found this Vishay P-channel MOSFET (SUP/SUB15P01-52) which comes
close, and that I *could* use at the cost of 2 more transistors and
resistors in the design. Unfortunately there seems to be no N-channel
equivalents. From what I see there are no IGBTs that cut it due to
Vce(sat).
Strictly speaking the switch should be 'on' by default, but I couldn't
find any depletion mode MOSFETs that would satisfy the Ron and
through-hole specs, that's why I am look for very low threshold
enhancement mode transistors.
Are the specs hopeless, or does anybody know of something useable?
Best,
- Cesar