Data Sheet

ADL8140

APPLICATIONS INFORMATION

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Rev. 0 | 15 of 18

The basic connections for operating the ADL8140 over the speci-

fied frequency range are shown in Figure 50. No external biasing

inductor is required, allowing the 1.5 V supply to be connected

to the VDD pin. It is recommended to use 0.1 µF and 100 pF

power supply decoupling capacitors. The power supply decoupling

capacitors shown in Figure 50 represent the configuration used to

characterize and qualify the ADL8140.

To set the IDQ, connect a resistor, R2, between the RBIAS and VDD

pins. A default value of 562 Ω is recommended, which results in

a nominal IDQ of 35 mA. The RBIAS pin also draws a current that

varies with the value of RBIAS, and this current is typically a few mA.

Do not leave the RBIAS pin open.

The RFIN and RFOUT pins are internally AC-coupled. If the

RFOUT pin is connected to a DC bias level other than 0 V,

AC-couple the RFOUT pin because of the internal DC path to

ground on RFOUT.

Figure 50. Typical Application Circuit

RECOMMENDED BIAS SEQUENCING

RF input power should be applied after VDD has turned on and

should be removed before VDD is turned off.

Table 9. Recommended Bias Resistor Values for Various IDQ Values, VDD =

1.5 V

RBIAS (Ω)

IDQ (mA)

IDQ_AMP (mA)

IRBIAS (mA)

1347

20

19.25

0.75

948

25

24

1

709

30

28.6

1.4

562

35

33.3

1.7

445

40

38

2

366

45

42.6

2.4

Table 10. Recommended Bias Resistor Values for Various Supply Voltages,

IDQ = 35 mA

RBIAS (Ω)

VDD (V)

335

1.2

404

1.3

562

1.5

722

1.7

1024

2.0

1630

2.5

2370

3.0

3301

3.5