REV. A

AD8350

–12–

EVALUATION BOARD

Figure 13 shows the schematic of the AD8350 evaluation board,

for SOIC, as it is shipped from the factory. The board is config-

ured to allow easy evaluation using single-ended 50

Ω test

equipment. The input and output transformers have a 4-to-1

impedance ratio and transform the AD8350’s 200

Ω input and

output impedances to 50

Ω. In this mode, 0 Ω resistors (R1 and

R4) are required.

To allow compensation for the insertion loss of the transform-

ers, a calibration path is provided at Test In and Test Out. This

consists of two transformers connected back to back.

To drive and load the board differentially, transformers T1 and

T2 should be removed and replaced with four 0

Ω resistors

(0805 size); Resistors R1 and R4 (0

Ω) should also be removed.

This yields a circuit with a broadband input and output impedance

of 200

Ω. To match to impedances other than this, matching

components (0805 size) can be placed on pads C1, C2, C3, C4,

L1, and L2.

8

7

6

5

1

2

3

4

AD8350

–

C5

0.1 F

L1

(OPEN)

L2

(OPEN)

C3

0.001 F

C2

0.001 F

C4

0.001 F

1

2

3

A

B

SW1

61

R2

0

C1

0.001 F

R1

0

T1: TC4-1W

(MINI CIRCUITS)

IN–

IN+

R3

0

6

T2: TC4-1W

(MINI CIRCUITS)

R4

0

OUT–

OUT+

16

T4: TC4-1W

(MINI CIRCUITS)

TEST OUT

61

T3: TC4-1W

(MINI CIRCUITS)

TEST IN

1

Figure 13. Evaluation Board