AD8352

Rev. A | Page 16 of 20

EVALUATION BOARD

An evaluation board is available for experimentation of various parameters such as gain, common-mode level, and distortion. The output

network can be configured for different loads via minor output component changes. The schematic and evaluation board artwork are

presented in Figure 38, Figure 39, and Figure 40. All discrete capacitors and resistors are Size 0402, except for C1 (3528-B).

Table 9. Evaluation Board Circuit Components and Functions

Component

Name

Function

Additional Information

C8, C9

Capacitors

C8 and C9 are bypass capacitors.

C8 = 0.1 μF, C9 = 0.1 μF

Distortion

Tuning

Components

Distortion Adjustment Components. Allows for third-order distortion

adjustment HD3.

Typically, both are open

above 300 MHz

(microwave) Multilayer Chip

402 capacitor

R1, R2, R3, R4,

R5, R6, T2, C2,

C3

Resistors,

Transformer,

Capacitors

Input Interface. R1 and R4 ground one side of the differential drive

interface for single-ended applications. T2 is a 1-to-1 impedance ratio

balun to transform a single-ended input into a balanced differential

signal. R2 and R3 provide a differential 50 Ω input termination. R5 and

R6 can be increased to reduce gain peaking when driving from a high

source impedance. The 50 Ω termination provides an insertion loss of

6 dB. C2 and C3 provide ac-coupling.

T2 = M/A-COM, Inc. ETC1-1-13

R1 = open, R2 = 25 Ω,

R3 = 25 Ω, R4 = 0 Ω,

R5 = 0 Ω, R6 = 0 Ω,

C2 = 0.1 μF, C3 = 0.1 μF

R7, R8, R9, R11,

R12, R13, R14,

T1, C4, C5

Resistors,

Transformer,

Capacitors

Output Interface. R13 and R14 ground one side of the differential

output interface for single-ended applications. T1 is a 1-to-1 impedance

ratio balun to transform a balanced differential signal to a single-

ended signal. R8, R9, and R12 are provided for generic placement of

matching components. R7 and R11 allow additional output series

resistance when driving capacitive loads. The evaluation board is

configured to provide a 200 Ω to 50 Ω impedance transformation

with an insertion loss of 11.6 dB. C4 and C5 provide ac-coupling. R7

and R11 provide additional series resistance when driving capacitive

loads.

T1= M/A-COM ETC1-1-13

R7 = 0 Ω, R8 = 86.6 Ω,

R9 = 57.6 Ω,

R11 = 0 Ω, R12 = 86.6 Ω,

R13 = 0 Ω, R14 = open

C4 = 0.1 μF, C5 = 0.1 μF

Resistor

Refer to Table 5 and Table 6 when selecting the gain resistor.

gain of 10 dB

C1, C6, C7

Capacitors

Power Supply Decoupling. The supply decoupling consists of a 10 μF

capacitor to ground. C6 and C7 are bypass capacitors.

C1 = 10 μF

C6 = 0.1 μF, C7 = 0.1 μF

EVALUATION BOARD LOADING SCHEMES

The AD8352 evaluation board is characterized with two load

configurations representing the most common ADC input

resistance. The loads chosen are 200 Ω and 1000 Ω using a

broadband resistive match. The loading can be changed via R8,

R9, and R12 giving the flexibility to characterize the AD8352

evaluation board for the load in any given application. These

loads are inherently lossy and thus must be accounted for in

overall gain/loss for the entire evaluation board. Measure the

gain of the AD8352 with an oscilloscope using the following

procedure to determine the actual gain:

1.

Measure the peak-to-peak voltage at the input node

(C2 or C3).

2.

Measure the peak-to-peak voltage at the output node

(C4 or C5).

3.

Compute gain using the formula

Gain = 20log(V

/V )

OUT

IN

Table 10. Values Used for 200 Ω and 1000 Ω Loads

Component

200 Ω Load (Ω)

1000 Ω Load (Ω)

R8

86.6

487

R9

57.6

51.1

R12

86.6

487