AD8334-EVALZ资料

Quad VGA and Ultralow Noise Preamplifierwith Programmable RIN Evaluation BoardAD8334-EVAL

GENERAL DESCRIPTION

The AD8334-EVAL is a platform for the test and evaluation of the AD8334 variable gain amplifier (VGA). The board is shipped assembled and tested, and users only need to connect the signal and VGAIN sources and a single 5 V power supply. Figure 1 is a photograph of the board.

FEATURES

Factory tested

Provisions for direct measurement

Optional differential-to-single-ended output Provision for LNA output measurement Selectable high or low gain Provision for input calibration Provision for clamping resistors Single-supply operation

APPLICATIONS

Test gain interface circuitry

Evaluate clamping characteristics

Evaluate effects of dynamic drive signals TGC evaluate system characteristics Medical ultrasound systems Industrial ultrasound systems PC layout guidance

Evaluate performance with real-world signals

06225-001

Figure 1.

Rev. 0

Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2006 Analog Devices, Inc. All rights reserved.

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AD8334-EVAL

Measurement Setup.......................................................................5 Board Layout and Parts List.........................................................5 Ordering Information.......................................................................8 Ordering Guide.............................................................................8 ESD Caution...................................................................................8

TABLE OF CONTENTS

Features..............................................................................................1 Applications.......................................................................................1 General Description.........................................................................1 Revision History...............................................................................2 Configuring the Input Impedance.............................................3 Schematic.......................................................................................4

REVISION HISTORY

7/06—Revision 0: Initial Version

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AD8334-EVAL

CONFIGURING THE INPUT IMPEDANCE

The board is built and tested using the components shown in black (see Figure 2). Provisions are made for optional

components (shown in gray) that can be installed at the user’s discretion. As shipped, the input impedances of the low noise amplifiers (LNAs) are configured for 50 Ω to match the output impedance of most signal generators and network analyzers. Input impedances up to 6 kΩ can be realized by changing the values of the feedback resistors, RFB1, RFB2, RFB3, RFB4, and shunt capacitors, C6, C8, C10, and C12. See the AD8331/AD8332/

AD8334 data sheet for additional details on this circuit feature. For reference, Table 1 lists standard values of 1% resistors for some typical values of input impedance. Of course, if the user has determined that the source impedance falls between these values, the feedback resistor value can be calculated accordingly. Note that the board is designed to accept standard surface-mount, size 0603 components.

06225-002Table 1. LNA External Component Values for Common Source Impedances

RIN (Ω) RFB1, RFB2, RFB3, RFB4 (Ω, ±1%) 50 274 75 412 100 562 200 1.13 k 500 3.01 k 6 k No resistor

C6, C8, C10, C12 (pF)

22 12 8 1.2 No capacitor No capacitor

Figure 2. Assembly

Using the Clamp Circuit

The board is shipped with no resistors installed in the spaces provided for clamp-circuit operation. Note that each pair of channels shares a clamp resistor, and the value is selected the same as it is in the AD8331/AD8332/AD8334 data sheet. If the output clamping is desired, the resistors are installed in R49 and R50. The peak-to-peak clamping level is application dependent, and appropriate values are listed in the AD8331/AD8332/ AD8334 data sheet.

Driving the VGA from an External Source, or Using the LNA to Drive an External Load

Appropriate components can be installed if the user wishes to drive the VGA directly from an external source or to evaluate the LNA output. If the LNA is used to drive off-board loads or cables, small value series resistors (47 Ω to 100 Ω) are recommended for LNA decoupling. These can be installed in the R10, R11, R14, R15, R18, R19, R22, and R23 spaces. Provisions are made for surface-mount SMA connectors that can be used for driving from either direction. If the LNA is not used, it is recommended that the capacitors, C16, C17, C21, C22, C26, C27, C31, and C32, be carefully removed to avoid driving the outputs of the LNAs.

Viewing Signals

The preferred signal detector is a high impedance differential probe, such as the Tektronix P6247, 1 GHz differential probe, connected to the 2-pin headers (VO1, VO2, VO3, or VO4), as shown in Figure 4. The low capacitance of this probe has the least effect on the performance of the device of any detection method tried. The probe can also be used for monitoring input signals at IN1, IN2, IN3, or IN4. It can also be used for probing other circuit nodes; however, beware that the 200 kΩ input impedance can affect certain circuits.

Differential-to-single-ended transformers are provided for single-ended output connections. Note that series resistors are provided to protect against accidental output overload should a 50 Ω load be connected to the connector. Of course, the effect of these resistors is to limit the bandwidth. If the load connected to the SMA is > 500 Ω, the 237 Ω series resistors, RX1, RX2, RX3, RX4, RX5, RX6, RX7, and RX8, can be replaced with 0 Ω values.

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AD8334-EVAL

SCHEMATIC

Figure 3. Evaluation Board Schematic

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AD8334-EVAL

BOARD LAYOUT AND PARTS LIST

The evaluation board circuitry uses four conductor layers. The two inner layers are ground, and all interconnecting circuitry is located on the outer layers. Figure 5, Figure 6, Figure 7, Figure 8, and Figure 9 illustrate the copper patterns, and Table 2 is a parts list.

MEASUREMENT SETUP

The basic board connections for measuring bandwidth are shown in Figure 4. A 5 V, 200 mA (minimum) power supply is required, and a low noise voltage reference supply is required for VGAIN.

PRECISIONVOLTAGEREFERENCE(FORVGAIN)PROBEPOWERSUPPLYGAINCONTROLVOLTAGEGNDNETWORKANALYZERDIFFERENTIALPROBESIGNALINPUTPOWERSUPPLY+5VGND06225-004

Figure 4. Typical Board Test Connections (One Channel Shown)

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AD8334-EVAL

Figure 7. Inner Layer No. 1

06225-00706225-00806225-005

Figure 5. Component Side Copper

06225-006

Figure 8. Inner Layer No. 2

Figure 6. Wiring Side Copper

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AD8334-EVAL

06225-009 Figure 9. Component Side Silk-Screen

Table 2. Parts List

Qty. 1 6 2 36

Name Test Loop Test Loops Test Loops Capacitors

Description

0.125” diameter, red 0.125” diameter, blk 0.125” diameter, purple 0.1 μF, 16 V, 0603

Reference Designator +5V

GND1 to GND6 GAIN12, GAIN34

C1, C2, C3, C4, C5, C7, C9, C11, C13, C16, C17, C21, C22, C26, C27, C31, C32, C34, C36, C39, C41, C44, C46, C49, C51, C53, C55, C57, C59, C62, C, C67, C69, C71, C75, C77 C6, C8, C10, C12 C80, C82

CFB1, CFB2, CFB3, CFB4 J1, J2, J3, J4, J5, J6, J7, J8, VO1, VO2, VO3, VO4

INHI1 to INHI4, VOH1to VOH4

L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12, L13, L14, L15, L16, L17, L34 R26, R28, R31, R33, R36, R38, R41, R43 RFB1, RFB2, RFB3, RFB4

RX1, RX2, RX3, RX4, RX5, RX6, RX7, RX8 EN12, EN34, J11, J12 T1, T2, T3, T4 U1

Mount to Wiring Side of Board Install at J1 to J8; J11: up, J12: high; EN12 (lower position); EN34 (lower position) C14

IN1 to IN4, CB1 to CB8, LO1 to LO4, LON1 to LON4, LOP1 to LOP4, R10, R11, R14, R15, R18, R19, R22, R23, R49, R50

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Manufacturer Bisco, Inc. Bisco, Inc. Bisco, Inc. KEMET Corp. Mfg. Part No. TP-104-01-02 TP-104-01-00 TP-104-01-07 C0603C104K4RAC

4 Capacitors 2 Capacitors 4 Capacitors 12 Headers 8 18 8 4 8 4 4 1 4 12

Connectors Ferrite Beads Resistors Resistors Resistors Headers Transformers IC Foot

Mini-Jump Jumpers

22 pF, 5%, 50,V, 0603 1 nF, 10%, 100 V, 0603 18 nF, 0603 0.1” 2-Pin SMA Fem PC MT, RA 120 nH, 0603

237 Ω, 1%, 1/16W, 0603 274 Ω, 1%, 1/10W, 0603 100 Ω, 1%, 1/16W, 0603 0.1” 3-pin

RF 0.015 MHz to 300 MHz Quad VGA Bumper

Panasonic Panasonic Panasonic FCI ECJ-1VC1H220J ECJ-1VB2A102K ECJ-1VB1E183K 69157-102

Amphenol Corp. 901-143-6RFX

Murata BLM18BA750SN1D Panasonic ERJ-3EKF2370V Panasonic ERJ-3EKF2740V Panasonic ERJ-3EKF1 Molex 22-10-2031 Mini-Circuits T1-6T KK81 Analog Devices, Inc. AD8334ACPZ 3M SJ-67A11

FCI 65474-001 1 Capacitor 10 μF, 10 V, A Size Not inserted Nichicon Corp.

F931A106MAA

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AD8334-EVAL

ORDERING INFORMATION

ORDERING GUIDE

Model Description AD8334–EVAL Evaluation Board

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. EB06225-0-7/06(0)

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