How can I create a fixed voltage reference output voltage from a varying input voltage?

Question

Suppose I have the following:

• A voltage source that outputs a voltage between 10 and 14 V.

I need to generate a fixed reference voltage independent of the input voltage mentioned above. How can I do this?

Ideally I'd like my reference voltage not to vary more than 25 mV. So, say for instance, that the reference voltage is 5V then when input voltage is 14 V, the reference voltage must be at most 5.025V and when input voltage is 9 V the reference must be at least 4.975 V.

My first thought is to use a zener diode, maybe 5.6V or 3V. But I don't like this solution as it is a bit power consuming. I don't have any specific maximum value for power consumption, but I'd like it to be as low as possible. Is there any IC that can do this by consuming less than a zener?

I could also use an LM317 but since the voltage reference would feed a few comparators I thought the LM317 might be an overkill.

Answer 1

Use a voltage reference chip like the REF02. It has : -

• WIDE SUPPLY RANGE: 8V to 40V
• OUTPUT VOLTAGE: +5V ±0.2% max
• EXCELLENT TEMPERATURE STABILITY: 10ppm/°C max (–40°C to +85°C)
• LOW NOISE: 10μVPP max (0.1Hz to 10Hz)
• EXCELLENT LINE REGULATION: 0.01%/V max
• EXCELLENT LOAD REGULATION: 0.008%/mA max
• LOW SUPPLY CURRENT: 1.4mA max

There are gazillions to choose from and many that only need a few hundred microamps.