reference voltage generation

[rogger123]

how do i generate a reference voltage of 2v from a 3v supply using active devices, mos transistors using 1.6u tech

 

[batdin]

LM4120-2.048
Typical dropout:200mV/5mA

 

[sunking]

bandgap
x1Vbe+X2|deltaVbe|

 

[jordan76]

The choices mainly depend on your application requirements(voltage,temperature,power,accuracy,cost,etc).

Bandgap and LDO are certainly among them.

regards,
jordan76

 

[raymond_luo2003]

That depends what kinds of application you are looking for. If you only want to get a precise reference, BandGap circuit could be a good choice. You can find alot of example circuit in the analog design textbook. If you want that reference has strong driving capability, you probably need a output buffer.

Raymond

 

[zkxing432]

LM4120-2.048
Typical dropout:200mV/5mA

 

[leebluer]

Bandgap is a good choice to realize a precise voltage reference. but to get 2V output under 3V supply voltage, you need to do some change. Good luck

 

[scr]

Well it depends on what you need the 2v for, ie., does it need to have a drive capability to power other circuits , or is it needed as a reference.

If you need a stable reference , bandgap is the best bet. Even in 1.6u technology, this should not be too difficult to implemet.

However if you need thid voltage to power some other circuitry running at 2V , the you need a LDO regulator. Being 2v in a 3v supply, with high Vt(I assume) you will have to use a PMOS driver in the final stage instead of the conventional source follower.Though this will have a higher output resistance you can compensate it with a cap.

 

[nj_jack]

LM317 is a very good choice for you.
it can get many voltage through changing resistance value.

 

[nuiscet]

Bandgap is a a precise voltage reference around 1.2v. but for 2v output voltage, it is very difficult.

 

[wanily1983]

if u only use 2v as a reference, u can design a circuit to get a bandgap voltage about 1.2v then use negative to boost the voltage to 2v. maybe like this

 

[nuiscet]

But the resistance has temperature-dependence , the bandgap vref hasn't temperature-dependence. So the output of upside plot will have temperature-dependence.

 

[zenisle]

this problem is like create digital VDD from analog VDD.

 

[wanily1983]

Vout=Vref*(R2+R1)/R1, the resistance tf can cancel for each other.

 

[pfd001]

bandgap reference is a good choice

 

[horzonbluz]

The idea of wanily1983 is a good method.
But i think the good one is the one fit for your design need!