Data Sheet

ADL8105

APPLICATIONS INFORMATION

analog.com

Rev. A | 19 of 22

The basic connections for operating the ADL8105 over the speci-

fied frequency range are shown in Figure 74. No external biasing

inductor is required, allowing the 5 V supply to be connected to

the VDD pin. It is recommended to use 0.01 µF and 100 pF

power supply decoupling capacitors. The power supply decoupling

capacitors shown in Figure 74 represent the configuration used to

characterize and qualify the ADL8105.

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

pins. A default value of 392 Ω is recommended, which results in

a nominal IDQ of 90 mA. Table 9 shows how IDQ and IDQ_AMP vary

vs. RBIAS. The RBIAS pin also draws a current that varies with the

value of RBIAS (see Table 9). Do not leave the RBIAS pin open.

Correct sequencing of the dc and RF power is required to safely

operate the ADL8105. During power-up, apply VDD before the RF

power is applied to RFIN, and during power-off, remove the RF

power from RFIN before VDD is powered off.

Figure 74. Typical Application Circuit

RECOMMENDED BIAS SEQUENCING

See the ADL8105-EVALZ user guide for the recommended bias

sequencing information.

Table 9. Recommended RBIAS Values for VDD = 5 V

RBIAS (kΩ)

IDQ (mA)

IDQ_AMP (mA)

IRBIAS (mA)

5

40

39.18

0.82

2.75

50

48.6

1.4

1.7

60

57.9

2.1

1.1

70

67.2

2.8

0.73

80

76.4

3.6

0.392

90

85

5

0.305

100

94.6

5.4

0.18

110

103.6

6.4