REV. B

AD8315

–15–

Using the Chip Scale Package

On the underside of the chip scale package, there is an exposed

paddle. This paddle is internally connected to the chip’s ground.

There is no thermal requirement to solder the paddle down to the

printed circuit board’s ground plane. However, soldering down

the paddle has been shown to increase the stability over frequency

of the AD8315 ACP’s response at low input power levels (i.e., at

around –45 dBm) in the DCS and PCS bands.

Evaluation Board

Figure 11 shows the schematic of the AD8315 MSOP evaluation

board. The layout and silkscreen of the component side are

shown in Figures 12 and 13. An evaluation board is also available

for the LFCSP package (for exact part numbers, see Ordering

Guide). Apart from the slightly smaller device footprint, the

LFCSP evaluation board is identical to the MSOP board. The

board is powered by a single supply in the range, 2.7 V to 5.5 V.

The power supply is decoupled by a single 0.1

F capacitor.

Table II details the various configuration options of the

evaluation board.

R3

J2

VAPC

R4

(OPEN)

C2

(OPEN)

NC = NO CONNECT

RFIN

ENBL

VSET

VPOS

VAPC

NC

COMM

FLTR

AD8315

1

2

3

4

5

6

7

8

R2

52.3

C4

(OPEN)

C1

0.1 F

R1

J1

LK2

LK1

VPOS

SW1

RFIN

J3

VSET

AD8031

R7

C3

0.1 F

R8

10k

C5

0.1 F

R6

R5

0

0

16.2k

17.8k

10k

TP1

TP2

Figure 11. Evaluation Board Schematic

Table II. Evaluation Board Configuration Options

Component

Function

Default Condition

TP1, TP2

Supply and Ground Vector Pins

Not Applicable

SW1

Device Enable: When in Position A, the ENBL pin is connected to VPOS and

SW1 = A

the AD8315 is in operating mode. In Position B, the ENBL pin is grounded

putting the device in power-down mode.

R1, R2

Input Interface: The 52.3

W resistor in Position R2 combines with the

R2 = 52.3

W (Size 0603)

AD8315’s internal input impedance to give a broadband input impedance

R1 = 0

W (Size 0402)

of around 50

W. A reactive match can be implemented by replacing R2 with

an inductor and R1 (0

W) with a capacitor. Note that the AD8315’s RF input

is internally ac-coupled.

R3, R4, C2

R4 = C2 = Open (Size 0603)

W (Size 0603)

C1

Power Supply Decoupling: The nominal supply decoupling consists of a

C1 = 0.1

mF (Size 0603)

0.1

mF capacitor.

C4

C4 = Open (Size 0603)

capacitor between FLTR (Pin 4) and ground.

LK1, LK2

Measurement Mode: A quasi-measurement mode can be implemented by

LK1, LK2 = Installed

(0.01

mF or greater) must be installed in C4.