AD215

REV. 0

–7–

POWERING THE AD215

The AD215 is powered by a bipolar

±15 V dc power supply

connected as shown in Figure 11. External bypass capacitors

should be provided in bused applications. Note that a small

LO pin (Pin 37). Therefore, the OUT LO terminals should be

bused together and referenced at a single “Analog Star Ground”

to the

±15 V dc supply common as illustrated Figure 11.

ANALOG STAR GROUND

SIG COM

PWR RTN

+15V dc

COM

–15V dc

2.2µF

37

42

43

44

42

44

43

2.2µF

37

Figure 11. Typical Power Supply Connections

Power Supply Voltage Considerations

The rated performance of the AD215 remains unaffected for

power supply voltages in the

±14.5 V dc to ±16.5 V dc range.

Voltages below

±14.25 V dc may cause the AD215 to cease op-

erating properly.

Note: Power supply voltages greater than

±17.5 V dc may damage

the internal components and consequently should not be used.

USING THE AD215

Unity Gain Input Configuration

The basic unity gain configuration for input signals of up to

±10 V is shown in Figure 12.

IN+

IN–

FB

IN COM

OUT HI

OUT LO

PWR

RTN

COM

TRIM

OUTPUT FILTER,

BUFFER AND

TRIM CIRCUITRY

1

3

4

2

38

36

37

43

AD215

Figure 12. Basic Unity Gain

Noninverting Configuration for Gain Greater Than Unity

Figure 13 shows how to achieve a gain greater than one while

continuing to preserve a very high input impedance. A recom-

mended PC board layout for multichannel applications is shown

in Figure 20b.

IN+

IN–

FB

IN COM

OUT HI

OUT LO

PWR

RTN

COM

TRIM

OUTPUT

FILTER,

BUFFER

AND

TRIM

CIRCUITRY

1

3

4

2

38

36

37

43

AD215

47pF

Figure 13. Noninverting Input Configuration for

Gain > 1 V/V

In this circuit, the gain equation is as follows:

where:

= Output Voltage (V)

= Feedback Resistor Value (

Ω)

= Gain Resistor Value (

Ω)

constraints:

• The total impedance of the gain network should be less than

10 k

Ω.

±10 V. Note that

for each mA drawn by the feedback resistor, the isolated

power supply drive capability decreases by 1 mA.

shown.

Note: The 2 k

Ω input resistor (R

signal source and the IN+ terminal in Figures 12 and 13 is rec-

ommended to limit the current at the input terminals of the to

5.0 mA when the AD215 is not powered.