Data Sheet

ADL8143

RECOMMENDED POWER MANAGEMENT CIRCUIT

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Rev. 0 | 16 of 17

Figure 52 shows a recommended power management circuit that

uses the LT3083 low dropout (LDO) regulator. The LT3083 output

load current is supplied to the IN pin. Power for the on-board control

is applied to the VCONTROL pin. A voltage that is at least 1.4 V

higher than the output voltage must be applied to the VCONTROL pin.

In Figure 52, VCONTROL has been set to 5 V but could be set as low

as 2.9 V for a 1.5 V output voltage. The current into the VCONTROL

pin is typically 1.7% of the total output current.

The LT3083 can provide up to 3 A of load current. In a phased array

application, a single LT3083 can easily provide bus power for all of

the ADL8143 devices in a 64-element array. A dropout voltage of

500 mV is assumed based on a load current of 3 A. If the required

load current is lower, the voltage on the IN pin of the LT3083 can be

reduced to improve efficiency. For example, for a load current of 1

A, the dropout voltage drops to a worst-case value of 160 mV.

For applications that require a lower dropout voltage, the LT3033

can be used. For a 3 A load, the worst-case dropout voltage is 240

mV in the LT3033.

Table 10 provides recommended resistor values to set the other

output voltages. In each case, the minimum VIN voltage is specified

based on a 3 A load and a 500 mV dropout voltage.

Table 10. Recommended Resistor Values for the Various LDO Output Voltages

LDO VOUT (V)

R2 (kΩ)

Minimum VDD (V)

1.2

24.3

1.7

1.5

30.1

2.0

2.0

40.2

2.5

2.5

49.9

3.0

3.0

60.4

3.5

3.3

66.5

3.8

3.5

69.8

4.0

Figure 52. Recommended Power Management Circuit