AD8331 Evaluation Board AD8331-EVAL GENERAL DESCRIPTION The AD8331 evaluation board is a platform for testing and evaluating the AD8331 variable gain amplifier (VGA). The board is provided completely assembled and tested; therefore, the user only needs to connect an input signal, VGAIN sources, and a single 5 V power supply. USER SUPPLIED OPTIONAL COMPONENTS The input impedance of the LNA is configured for 50 Ω to accommodate most signal generators and network analyzers. Input impedances up to 6 kΩ can be realized by changing the values of RFB and CSH. Consult the AD8331 data sheet for details on this circuit feature. See Table 1 for typical values of input impedance and corresponding components. Table 1. LNA External Component Values for Common Source Impedances RIN (Ω) 50 75 100 200 500 6k RFB (Ω, Nearest 1% Value) 274 412 562 1.13 k 3.01 k ∞ CSH (pF) 22 12 8 1.2 None None The board is designed for 0805 size surface-mount components. Space is provided for various popular configurations of overload diodes at locations D1, D2, or D3. The LNA can be evaluated on its own. If so used alone, it must be ac-coupled with capacitors at its differential output. Typical values are 0.1 μF, and they are installed at Position C1 and Position C2. Resistors of 0 Ω are installed at R4 and R8, unless capacitive loads larger than 10 pF are connected to the SMA connectors, LON, and LOP (such as coaxial cables.) In that event, small value resistors (68 Ω to 100 Ω) must be installed at R4 and R8. A resistor can be inserted at RCLMP if output clamping is desired. Consult the AD8331 data sheet for appropriate values. 04589-001 As shown in the schematic in Figure 2 (fixed), the board has provisions for optional components. The basic components are shown in black, and the optional components, which can be installed at the user’s discretion, are shown in grey. Figure 1. AD8331-EVAL Top View The preferred signal detection method is a differential probe connected to VO, as shown in Figure 3. Single-ended loads can be connected using the board edge SMA connector, VOH. Be sure to take into account the 25.8 dB attenuation incurred when using the board in this manner. MEASUREMENT SETUP The basic board connection for measuring bandwidth is shown in Figure 3. A 5 V, 100 mA minimum power supply, and a low noise, voltage reference supply for GAIN is required. Table 2 lists jumpers, and Figure 3 shows their function and positions. Table 2. Jumper Functions No. ENBL ENBV W5, W6 Mode Function Enables the LNA when inserted in the top position Enables the VGA when inserted in the top position Connects the AD8331’s outputs to the SMA connectors Bottom, gain increases with VGAIN; Top, gain decreases with VGAIN HI_LO Top, HI gain; bottom, LO gain (shown in Hi gain position) BOARD LAYOUT AND PARTS LIST The evaluation board circuitry uses four conductor layers. The two inner layers are grounded, and all interconnecting circuitry is located on the outer layers. Figure 5 to Figure 8 illustrate the copper patterns. Table 3 is a part’s list. Rev. A 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. AD8331-EVAL GND1 GND2 GND +5V GND3 GND4 +C3 10µF 10V L1 120nH FB 1 LON CSH 22pF CFB 0.018µF RFB 274Ω 3 +5V L2 120nH FB R4 20 +5V 2 1 COMM CINH 0.1µF 3 D2 PROBE 2 LMD ENBL INH 19 LNA EN DIS +5V DUT AD8331ARQ VPS ENBV LON COMM 18 DIS C6 0.1µF C1 4 17 L3 120nH FB LO R8 5 LOP VOL LOP 6 COML VOH C24 R16 W5 0.1µF 237Ω 16 R44 100Ω C2 C16 0.1µF 15 VO R43 100Ω L4 120nH FB VIP VPOS +5V DOWN 9 VIN MODE HILO CLMP 13 +5V C32 0.1µF HI HI_LO LO 12 C35 0.1µF UP GAIN 10 C34 1nF GAIN VCM VOH R20 237Ω L5 120nH FB 14 +5V 8 T1 1:1 C26 0.1µF W6 C14 0.1µF 7 W1 MODE EN VGA RCLMP 11 VCM C18 0.1µF 04589-002 INH CLMD 0.1µF NOTES 1. COMPONENTS IN GREY ARE OPTIONAL AND USER SUPPLIED. Figure 2. Schematic of Evaluation Board 4395A ANALYZER 1103 TEKPROBE POWER SUPPLY GND E3631A POWER SUPPLY DIFFERENTIAL PROBE 5V DP8200 PRECISION VOLTAGE REFERENCE (FOR VGAIN) INSERT JUMPERS W5 AND W6 TO USE OUTPUT TRANSFORMER AND VOH SMA Figure 3. Typical Board Test Connections Rev. A | Page 2 of 4 04589-003 GND 04589-004 04589-007 AD8331-EVAL Figure 7. Internal Layer Ground 04589-008 04589-005 Figure 4. Top Silkscreen Figure 5. Primary Side Copper 04589-006 Figure 8. Power Plane Figure 6. Secondary Side Copper Rev. A | Page 3 of 4 AD8331-EVAL Table 3. Parts List Qty 5 1 2 2 1 10 Name Inductors Resistor Resistors Resistors Capacitor Capacitor Description Ferrite Bead, 120 nH, 0603 SM, 274 Ω, 1%, 1/10 W, 0603 SM, 237 Ω, 1%, 1/10 W, 0603 SM, 100 Ω, 1%, 1/10 W, 0603 0.018 μF, 10%, X7R, 0603 0.1 μF, 50 V, 0603 1 1 6 Capacitor Capacitor Shunt 1000 pF, 50 V, 0603 10 μF, 10V Tantalum Shunt 1 1 4 Capacitor Transformer Bumper 22 pF, 50 V, 0603 RF, 0.015 MHz to 300 MHz Foot 1 3 4 2 1 5 1 Integrated Circuit Connector Connector Connectors Test Point Test Points Test Points Variable Gain Amplifier 2-Pin Header 3-Pin Header SMA, Right Angle PC Mount Red Loop Black Loop Purple Loop Reference Designation L1, L2, L3, L4, L5 RFB R16, R20 R43, R44 CFB C6, C14, C16, C18, C24, C26, C32, C35, CINH, CLMD C34 C3 HI_LO (HI), MODE (UP), ENBL (EN), ENBV (EN), W5, W6 CSH T1 Used as feet. Mount to wiring side of board at 4 corners DUT VO, W5, W6 ENBL, ENBV, HI_LO, MODE Fixed INH, VOH +5V GND, GND 1, GND 2, GND 3, GND 4 VCM Fixed Mfg. Murata Panasonic Panasonic Panasonic Panasonic Kemet Mfg. Part Number BLM18BA750SN1D ERJ-3EKF2740V ERJ-3EKF2370V ERJ-3EKF1 ECJ-1VB1E183K C0603C104K4RAC Panasonic Nichicon W. M. Berg ECJ-1VB2A102K F931A106MAA 65474-001 Panasonic Mini-Circuit 3M ECJ-1VC1H220J #T1-6T KK81 SJ-67A11 Analog Devices, Inc. W. M. Berg Molex Amphenol Bisco Bisco Bisco AD8331ARQ 69157-102 22-11-2032 901-143-6RFX TP-104-01-02 TP-104-01-00 TP-104-01-07 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. ORDERING GUIDE Model AD8331-EVAL Description Evaluation Board with AD8331ARQ ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04589-0-4/06(A) Rev. A | Page 4 of 4