REV. 0

ADR510

–5–

Adjustable Precision Voltage Source

The ADR510, combined with a precision low input bias op amp

such as the AD8610, can be used to output a precise adjustable

voltage. Figure 2 illustrates the implementation of this application

using the ADR510.

circuit, which is completely dependent on Resistors R2 and R1.

V

R2

R1

1

(4)

An additional capacitor in parallel with R2 can be added to filter

out high frequency noise. The value of C2 is dependent on the

value of R2.

R1

R2

AD8610

ADR510

1.0V

C2 (OPTIONAL)

Figure 2. Adjustable Precision Voltage Source

Output Voltage Trim

Using a mechanical or digital potentiometer, the output voltage

of the ADR510 can be trimmed

±0.5%. The circuit in Figure 3

illustrates how the output voltage can be trimmed, using a 10 k

Ω

potentiometer. Note that trimming using other resistor values

may not produce an accurate output from the ADR510.

R1

470k

POT

10k

ADR510

Figure 3. Output Voltage Trim

Using the ADR510 with Precision Data Converters

The compact ADR510 and its low minimum operating current

requirement make it ideal for use in battery-powered portable

instruments, such as the AD7533 CMOS multiplying DAC, that

use precision data converters.

Figure 4 shows the ADR510 serving as an external reference to

the AD7533, a CMOS multiplying DAC. Such a DAC requires

a negative voltage input in order to provide a positive output range.

In this application, the ADR510 is supplying a –1.0 V reference

to the REF input of the AD7533.

MSB

LSB

1

2

3

1

1

15

09

R2

ADR510

AD7533

Figure 4. ADR510 as a Reference for a 10-Bit

CMOS DAC (AD7533)

Precise Negative Voltage Reference

The ADR510 is suitable for use in applications where a precise

negative voltage reference is desired, including the application

detailed in Figure 4.

Figures 5 shows the ADR510 configured to provide a –1.0 V output.

–1.0V

R1

ADR510

Figure 5. Precise –1.0 V Reference Configuration

Since the ADR510 characteristics resemble those of a Zener

diode, the cathode shown in Figure 5 will be 1.0 V higher with

respect to the anode (V+ with respect to V– on the ADR510

package). Since the cathode of the ADR510 is tied to ground,

the anode must be –1.0 V.

R1 in Figure 5 should be chosen so that 100

µA to 10 mA is

provided to properly bias the ADR510.

R

V

I

DD

1

=

(5)

The R1 resistor should be chosen so that power dissipation is at

a minimum. An ideal resistor value can be determined through

manipulation of Equation 5.