MP8201 – LOW VOLTAGE, ADJUSTABLE SHUNT VOLTAGE REGULATOR

MP8201 Rev. 0.9

www.MonolithicPower.com

6

9/30/2009

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© 2009 MPS. All Rights Reserved.

APPLICATION INFORMATION

External Bias Resistor

In the case of shunt voltage references, an

between the supply voltage and the MP8201.

through the load and the IC.

The load and the supply voltage can vary, so

enough to supply the minimum current to the

MP8201 when the supply voltage is at its

minimum and the load current is at its maximum.

the quiescent current does not exceed 10mA

when the supply voltage is at its maximum and

the load current is at its minimum.

Q

L

OUT

SUPPLY

BIAS

I

I

V

V

R

+

−

=

Adjustable Precision Voltage Source

The MP8201 can be combined with a precision

op amp to produce a precise adjustable output

voltage. See Figure 1.

The output of the op amp is determined by the

gain of the circuit using the following equation:

2

R

1

R

1

+

=

An optional capacitor can be added in parallel

with R2 to filter out high frequency noise.

1

3

2

MP8201

3

4

1

+

-

MP 8101

R2

R1

C1

Figure 1—Adjustable Precision Voltage

Source

Output Voltage Trim

Using a mechanical or digital potentiometer, the

output voltage of the MP8201 can be trimmed

to ±0.5%. See Figure 2. Note that trimming

other resistor values may not produce an

accurate output from the MP8200.

1

3

2

MP8201

Figure 2—Output Voltage Trim

Precise Negative Voltage Reference

The MP8201 can be configured for use in

applications where a precise negative voltage

reference is needed.

R1

1

3

2

MP8201

Figure 3—Precise –1.0V Reference

Choose R1 such that 60µA to 20mA is provided

to properly bias the MP8201, using the equation:

I

V

1

R

DD

=