EVAL-AD5242DBZ User Guide UG-627 One Technology Way * P.O. Box 9106 * Norwood, MA 02062-9106, U.S.A. * Tel: 781.329.4700 * Fax: 781.461.3113 * www.analog.com Evaluation Board for the AD5242 Digital Potentiometer FEATURES GENERAL DESCRIPTION Full featured evaluation board used in conjunction with low voltage digiPOT motherboard (EVAL-MB-LV-SDZ) Multiple test circuits Multiple ac/dc input signals PC control via a separately purchased system demonstration platform (SDP-B or SDP-S) PC software for control This user guide describes the evaluation boards for evaluating the AD5242, a single-channel, 256-position, I2C-compatible digital potentiometer. EVALUATION KIT CONTENTS EVAL-AD5242DBZ evaluation board EVAL-MB-LV-SDZ motherboard CD that includes Self-installing software that allows users to control the board and exercise all functions of the device Electronic version of the AD5242 data sheet Electronic version of the EVAL-AD5242DBZ user guide The AD5242 supports single-supply 2.7 V to 5.5 V operation, making the device suitable for battery-powered applications and many applications requiring superior low temperature coefficient performance. In addition, the AD5242 uses a versatile I2C-compatible serial interface that operates in fast mode, allowing speeds of up to 400 kHz. This interface can be used to read back the wiper register and EEPROM content. The EVAL-AD5242DBZ daughter board and the EVAL-MBLV-SDZ motherboard can operate in single-supply mode and incorporate an internal power supply from the USB. Complete specifications for the AD5242 can be found in the AD5242 data sheet, which is available from www.analog.com and should be consulted in conjunction with this user guide when using the evaluation board. 11879-001 PHOTOGRAPH OF EVAL-AD5242DBZ WITH MOTHERBOARD AND SDP-B Figure 1. Digital Picture of Evaluation Board with Low Voltage DigiPOT Motherboard and System Demonstration Platform PLEASE SEE THE LAST PAGE FOR AN IMPORTANT WARNING AND LEGAL TERMS AND CONDITIONS. Rev. 0 | Page 1 of 16 UG-627 EVAL-AD5242DBZ User Guide TABLE OF CONTENTS Features .............................................................................................. 1 Test Circuits ...................................................................................4 Evaluation Kit Contents ................................................................... 1 Evaluation Board Software ...............................................................6 General Description ......................................................................... 1 Installing the Software ..................................................................6 Photograph of EVAL-AD5242DBZ with Motherboard and SDP-B .......................................................................................... 1 Running the Software ...................................................................6 Revision History ............................................................................... 2 Evaluation Board Schematics and Artwork ...................................8 Evaluation Board Hardware ............................................................ 3 Motherboard ..................................................................................8 Power Supplies .............................................................................. 3 Daughter Board .......................................................................... 12 Link Options ................................................................................. 3 Bill of Materials ............................................................................... 14 Operating the Software .................................................................7 Logic Outputs................................................................................ 3 REVISION HISTORY 5/14--Revision 0: Initial Version Rev. 0 | Page 2 of 16 EVAL-AD5242DBZ User Guide UG-627 EVALUATION BOARD HARDWARE POWER SUPPLIES LINK OPTIONS The EVAL-MB-LV-SDZ supports using single power supplies. Several link and switch options are incorporated on the EVALMB-LV-SDZ and EVAL-AD5242DBZ boards and must be set up before using the evaluation system. The functions of these link options are described in detail in Table 2 through Table 5. By default, the evaluation system is set up to be controlled by a PC via the SDP board. The evaluation board can be powered either from the SDP port or externally by the J1 and J2 connectors, as described in Table 1. All supplies are decoupled to ground using 10 F tantalum and 0.1 F ceramic capacitors. LOGIC OUTPUTS Header P6 of the evaluation board is connected to the O1 and O2 logic outputs of the AD5242. Table 1. Connector Functions Connector No. J1-1 J1-2 J2-1 J2-2 Label VDD AGND VLOGIC DGND Description Analog positive power supply, VDD Analog ground Digital supply Digital ground Voltage Min Max 2.7 V 5.5 V 2.7 V VDD Table 2. Link Functions Link No. A5 Power Supply VLOGIC A11 VDD A12 GND Options Digital supply select options: 3.3 V (from the SDP board) VLOGIC EXT (external supply from the J2 connector) Positive power supply select options: 5 V (from the SDP board) 3.3 V (from the SDP board) VDD (external supply from the J1 connector) AGND Rev. 0 | Page 3 of 16 Default Position 3.3 V 3.3 V AGND UG-627 EVAL-AD5242DBZ User Guide TEST CIRCUITS 1kHz The EVAL-AD5242DBZ and EVAL-MB-LV-SDZ incorporate several test circuits to evaluate the performance of the AD5242. DAC VDD 2 HPF AC+ AC AC_INPUT R34 The RDAC can be operated as a digital-to-analog converter (DAC), as shown in Figure 2. VDD 2 RDAC A A1 W1 W AC+ VOUT1 BUF-W1 B B1 VDD VDD RDAC A R35 A1 W1 W VOUT1 BUF-W1 B1 AGND 11879-002 BIAS AGND Table 3. AC Signal Attenuation Link Options Figure 2. DAC Link A9 Options AC+ A10 AC BIAS AGND Table 4 shows the options available for the voltage references. The output voltage is defined in Equation 1. VOUT = (VA - VB ) x 2 Depending on the voltage supply rails and the dc offset voltage of the ac signal, various configurations can be used, as described in Table 3. R35 2 BIAS Figure 3. AC Signal Attenuator B VDD VDD 11879-003 R34 RDAC 256 (1) where: RDAC is the code loaded in the RDAC register. VA is the voltage applied to the A terminal (A9 link). VB is the voltage applied to the B terminal (A10 link). 1 However, by using the R34 and R35 external resistors, you can reduce the voltage of the voltage references. In this case, use the A1 and B1 test points to measure the voltage applied to the A and B terminals and recalculate VA and VB in Equation 1. AC Signal Attenuation The RDAC can be used to attenuate an ac signal, which must be provided externally using the AC_INPUT connector, as shown in Figure 3. Conditions No dc offset voltage. AC signal is outside the voltage supply rails due to the dc offset voltage. DC offset voltage VDD/2.1 All other conditions. Use in conjunction with AC+ link.1 All other conditions. Recommended to ensure optimal total harmonic distortion (THD) performance. The signal attenuation is defined in Equation 2. R + RW Attenuation (dB) = 20 x log WB REND -TO -END where: RWB is the resistance between the W and B terminals. RW is the wiper resistance. REND-TO-END is the end-to-end resistance value. Table 4. DAC Voltage References Terminal A1 W1 B1 Link Settings Daughter Board Motherboard Hardwired to RDAC1 A9: AC+ position of daughter board A9: VDD position Hardwired to RDAC1 BUF-W1: inserted of daughter board Hardwired to RDAC1 A10: BIAS position of daughter board A10: AGND position P5: inserted Description Connects Terminal A1 to VDD/2 Connects Terminal A1 to VDD Connects Terminal W1 to an output buffer Connects Terminal B1 to VDD/2 Connects Terminal B1 to analog ground Closes the feedback loop of the second op amp in the AD8618 Rev. 0 | Page 4 of 16 (2) EVAL-AD5242DBZ User Guide UG-627 The RDAC can be operated as an inverting or noninverting signal amplifier and can support linear or pseudologarithmic gain. Table 5 shows the available configurations. RWB R38 R41 1.7k RDAC Figure 5. Noninverting Amplifier with Pseudologarithmic Gain G=- C1 10nF B2 B R42 RDAC RWB R38 (5) where RWB is the resistance between the W and B terminals. 11879-004 W R42 B The inverting amplifier with linear gain is shown in Figure 6, and the gain is defined in Equation 5. VOUT2 W2 B2 W A R43 and R42 can be used to set the maximum and minimum gain limits. where RWB is the resistance between the W and B terminals. R38 2.7k C1 10nF A2 R43 (3) Note that the input signal, VIN, must be negative. Figure 4. Noninverting Amplifier with Linear Gain R41 1.7k The noninverting amplifier with pseudologarithmic gain is shown in Figure 5, and the gain is defined in Equation 4. R G = 1 + WB R AW VIN (4) VOUT2 R38 2.7k C1 10nF W2 B2 W where: RWB is the resistance between the W and B terminals. RAW is the resistance between the A and W terminals. B R42 RDAC NOTES 1. THE INPUT SIGNAL, VIN, MUST BE NEGATIVE. 11879-006 VIN VOUT2 W2 The noninverting amplifier with linear gain is shown in Figure 4, and the gain is defined in Equation 3. G =1+ R41 1.7k VIN 11879-005 Signal Amplifier Figure 6. Inverting Amplifier with Linear Gain Table 5. Amplifier Selection Link Settings Amplifier Noninverting Gain Linear Pseudologarithmic Inverting Linear Link Settings Motherboard A7: LIN position, A6: N-INV position, P5: not inserted A8: N-INV position Hardwired to RDAC2 of A7: LOG position, daughter board, A6: N-INV position, P5: not inserted A8: N-INV position Hardwired to RDAC2 of A7: LIN position, daughter board, A6: INV position, P5: not inserted A8: INV position Daughter Board Hardwired to RDAC2 of daughter board, Rev. 0 | Page 5 of 16 VIN Range 0 V to VDD 0 V to VDD -VDD to 0 V UG-627 EVAL-AD5242DBZ User Guide EVALUATION BOARD SOFTWARE 2. INSTALLING THE SOFTWARE The EVAL-AD5242DBZ kit includes evaluation board software provided on a CD. The software is compatible with Windows(R) XP, Windows Vista, and Windows 7 (both 32-bit and 64-bit versions). Install the software before connecting the SDP board to the USB port of the PC to ensure that the SDP board is recognized when it is connected to the PC. 3. 4. 5. Start the Windows operating system and insert the CD. The installation software opens automatically. If it does not, run the setup.exe file from the CD. After the installation is complete, power up the evaluation board as described in the Power Supplies section. Connect the EVAL-AD5242DBZ and EVAL-MB-LV-SDZ to the SDP board and the SDP board to the PC. When the software detects the evaluation board, follow the instructions that appear to finalize the installation. 11879-007 1. 2. If the SDP board is not connected to the USB port when the software is launched, a connectivity error displays (see Figure 7). If a connectivity error is displayed, connect the evaluation board to the USB port of the PC and wait a few seconds, and then click Rescan and follow the instructions that appear on-screen. RUNNING THE SOFTWARE To run the program, do the following: Click Start > All Programs > Analog Devices > AD5242 > AD5242 Eval Board. (To uninstall the program, click Start > Control Panel > Add or Remove Programs > AD5242 Eval Board.) The main window of the EVAL-AD5242DBZ software then opens, as shown in Figure 8. 11879-008 1. Figure 7. Pop-Up Window Error Figure 8. EVAL-AD5242DBZ Software Main Window, Visual Mode Tab Rev. 0 | Page 6 of 16 EVAL-AD5242DBZ User Guide UG-627 OPERATING THE SOFTWARE Manual Control Tab The main window of the EVAL-AD5242DBZ software is divided into two tabs: Visual Mode and Manual Control. The Manual Control tab, as shown in Figure 9, allows customizing an I2C data-word by manually switching each serial data-word from 0 to 1 or from 1 to 0, as desired, and then clicking Write Registers. Data can also be read by clicking Read Registers. Visual Mode Tab The Visual Mode tab, as shown in Figure 8, is divided into two sections, with a block diagram on the right and command buttons on the left. Exiting the window closes the program. 11879-009 The block diagram allows updating the control register status. Each register value can easily be updated by changing the value in its respective block within the diagram. Figure 9. EVAL-AD5242DBZ Software Main Window, Manual Control Tab Rev. 0 | Page 7 of 16 UG-627 EVAL-AD5242DBZ User Guide EVALUATION BOARD SCHEMATICS AND ARTWORK 11879-010 MOTHERBOARD Figure 10. SDP Connector and Power Supply Rev. 0 | Page 8 of 16 EVAL-AD5242DBZ User Guide UG-627 11879-011 Figure 11. Schematic of Test Circuits Rev. 0 | Page 9 of 16 EVAL-AD5242DBZ User Guide 11879-012 UG-627 Figure 12. Schematic of Connectors to Daughter Board Rev. 0 | Page 10 of 16 UG-627 11879-013 EVAL-AD5242DBZ User Guide 11879-014 Figure 13. Component Side View 11879-015 Figure 14. Component Placement Drawing Figure 15. Layer 2 Side PCB Drawing Rev. 0 | Page 11 of 16 UG-627 EVAL-AD5242DBZ User Guide DAUGHTER BOARD VDD U1 5 VDD 2 A1 A1 W1 3 W1 4 B1 B1 O1 1 O1 A2 16 A2 W2 15 W2 B2 14 B2 O2 13 O2 VDD VDD C1 0.1F SHDN_N DIS 6 SCL 7 SCL SDA 8 C2 10F C3 0.1F C4 10F SDA DGND 9 ADDR0 AD0 ADDR1 10 AD1 VSS VSS DGND 11 12 VSS AD5242BRZ10 DGND RESET_N WP_N LRDAC_N DIS INDEP OP AMP PROTECTION P5 B2 1 W2 2 69157-102 INSERT P1, P2, P3, AND P4 ON THE SOLDER SIDE OF THE BOARD 1 2 3 4 5 LOGIC OUTPUT P3 P1 1 2 3 4 5 6 7 8 P2 A3 W3 B3 A4 W4 B4 22-03-2081 1 3 5 7 9 11 P2 2 4 6 8 10 12 A1 W1 B1 A2 W2 B2 TSW-105-08-G-S VSS VDD AGND 11879-016 DGND VLOGIC P4 1 2 3 4 5 69157-102 ADDR0 ADDR1 SDA SCL SYNC_N SDO SDI SCLK TSW-106-08-G-D 1 2 TSW-106-08-G-D TSW-105-08-G-S P6 O1 O2 Figure 16. Schematic of Daughter Board Rev. 0 | Page 12 of 16 UG-627 11879-017 EVAL-AD5242DBZ User Guide 11879-018 Figure 17. Component Side View 11879-019 Figure 18. Component Placement Drawing Figure 19. Layer 2 Side PCB Drawing Rev. 0 | Page 13 of 16 UG-627 EVAL-AD5242DBZ User Guide BILL OF MATERIALS Table 6. Motherboard Bill of Materials Qty 3 3 5 1 2 1 1 1 2 17 1 1 1 1 1 1 3 5 1 8 4 2 4 2 1 1 1 1 1 1 1 1 1 18 5 1 Reference Designator BUF-3, BUF-4, BUF-W1 A6, A7, A8 A5, A9, A10, A11, A12 J1 J7, J8 J4 J10 J5 J2, J3 R1, R3, R6, R7, R8, R9, R10, R11, R12, R13, R20, R22, R23, R34, R35, R42, R43 R2 R41 R21 R38 R14 R4 R5, R25, R26 R15, R16, R17, R18, R19 C1 C4, C9, C10, C11, C12, C17, C19, C21 C2, C6, C7, C14 C8, C13 C18, C20, C22, C5 C3, C15 C16 C34 L2 D1 U1 U2 U3 U4 U5 LRDAC, RESET, SYNC, WP, A1, A2, A3, A4, AGND, B1, VOUT_C1, VOUT_C2, VOUT3, VOUT4, W1, W2, W3, W4 +3.3V, +5V, EXT_VDD, VLOGIC, EXT_VSS Description 2-pin (0.1" pitch) header and shorting shunt 3-pin SIL header and shorting link 6-pin (3 x 2), 0.1" header and shorting block 3-pin terminal block (5 mm pitch) 4-pin SIL header Receptacle, 0.6 mm, 120-way 8-pin inline header; 100 mil centers 12-pin (2 x 6), 0.1" pitch header 2-pin terminal block (5 mm pitch) SMD resistor, 0 , 0.01, 0603 Supplier 1/Part Number FEC 1022247 and FEC 150411 FEC 1022248 and FEC 150410 FEC 148535 and FEC 150411 (36-pin strip) FEC 151790 FEC 1098035 Digi-Key H1219-ND FEC 1098038 FEC 1098051 FEC 151789 FEC 9331662 SMD resistor, 2.2 k, 0.01, 0603 SMD resistor, 1.7 k, 1%, 0603 Resistor, surge, 1.6 , 1%, 0603 SMD resistor, 2.7 k, 1%, 0603 SMD resistor, 100 , 1%, 0603 SMD resistor, 1 k, 0.01, 0603 SMD resistor, 100 k, 1%, 0603 SMD resistor, 33 k, 1%, 0603 SMD capacitor, 100 nF, 10%, 0805 SMD capacitor, 0.1 F, 10%, 0603 SMD capacitor, 0.1 F, 10%, 0603 SMD capacitor, 10 F, 10% Capacitor, 10 F, 20% Capacitor, 470 nF, 10%, 0603 Capacitor, 4.7 nF, 10%, 0603 Capacitor, 4.7 nF, 20% Inductor, SMD, 600Z Green SMD LED Two-port level translating bus switch Dual op amp Precision low dropout voltage regulator Operational amplifier I2C serial EEPROM, 64k, 2.5 V, MSOP-8 Terminal, PCB, black, PK100, test point FEC 1750676 FEC 1170811 FEC 1627674 FEC 1750678 FEC 9330364 FEC 9330380 FEC 9330402 FEC 9331034 FEC 1650863 FEC 1759122 FEC 3019482 FEC 197130 FEC 1190107 FEC 1414037 FEC 1414642 FEC 1432350 FEC 9526862 FEC 5790852 ADG3247BCPZ AD8652ARZ ADP3303ARZ-3.3 AD8618ARZ FEC 1331335 FEC 8731128 Terminal, PCB, red, PK100 FEC 8731144 FEC refers to Farnell Electronic Component Distributors; Digi-Key refers to Digi-Key Corporation. Rev. 0 | Page 14 of 16 EVAL-AD5242DBZ User Guide UG-627 Table 7. Daughter Board Bill of Materials Qty 1 1 3 2 2 1 1 2 1 Reference Designator U1 P8 P5, P6, P7 C2, C4 C1, C3 P1 P2 P3, P4 Description 256-position digital potentiometer 2-pin (0.1" pitch) header and shorting shunt 3-pin SIL header and shorting link 6.3 V, X5R, ceramic capacitor, 10 F, 20% 50 V, X7R, ceramic capacitor, 0.1 F, 10% Header, 2.54 mm, PCB, 1 x 8-way 12-pin (2 x 6), 0.1" pitch header 5-pin SIL header FEC refers to Farnell Electronic Component Distributors. Rev. 0 | Page 15 of 16 Supplier 1/Part Number AD5242BRZ10 FEC 1022247 and FEC 150411 FEC 1022248 and FEC 150410 GRM188R60J106ME47D GRM188R71H104KA93D FEC 1766172 FEC 1804099 FEC 1929016 UG-627 EVAL-AD5242DBZ User Guide NOTES I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors). ESD Caution ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality. Legal Terms and Conditions By using the evaluation board discussed herein (together with any tools, components documentation or support materials, the "Evaluation Board"), you are agreeing to be bound by the terms and conditions set forth below ("Agreement") unless you have purchased the Evaluation Board, in which case the Analog Devices Standard Terms and Conditions of Sale shall govern. Do not use the Evaluation Board until you have read and agreed to the Agreement. Your use of the Evaluation Board shall signify your acceptance of the Agreement. This Agreement is made by and between you ("Customer") and Analog Devices, Inc. ("ADI"), with its principal place of business at One Technology Way, Norwood, MA 02062, USA. Subject to the terms and conditions of the Agreement, ADI hereby grants to Customer a free, limited, personal, temporary, non-exclusive, non-sublicensable, non-transferable license to use the Evaluation Board FOR EVALUATION PURPOSES ONLY. Customer understands and agrees that the Evaluation Board is provided for the sole and exclusive purpose referenced above, and agrees not to use the Evaluation Board for any other purpose. Furthermore, the license granted is expressly made subject to the following additional limitations: Customer shall not (i) rent, lease, display, sell, transfer, assign, sublicense, or distribute the Evaluation Board; and (ii) permit any Third Party to access the Evaluation Board. As used herein, the term "Third Party" includes any entity other than ADI, Customer, their employees, affiliates and in-house consultants. The Evaluation Board is NOT sold to Customer; all rights not expressly granted herein, including ownership of the Evaluation Board, are reserved by ADI. CONFIDENTIALITY. This Agreement and the Evaluation Board shall all be considered the confidential and proprietary information of ADI. Customer may not disclose or transfer any portion of the Evaluation Board to any other party for any reason. Upon discontinuation of use of the Evaluation Board or termination of this Agreement, Customer agrees to promptly return the Evaluation Board to ADI. ADDITIONAL RESTRICTIONS. Customer may not disassemble, decompile or reverse engineer chips on the Evaluation Board. Customer shall inform ADI of any occurred damages or any modifications or alterations it makes to the Evaluation Board, including but not limited to soldering or any other activity that affects the material content of the Evaluation Board. Modifications to the Evaluation Board must comply with applicable law, including but not limited to the RoHS Directive. TERMINATION. ADI may terminate this Agreement at any time upon giving written notice to Customer. Customer agrees to return to ADI the Evaluation Board at that time. LIMITATION OF LIABILITY. THE EVALUATION BOARD PROVIDED HEREUNDER IS PROVIDED "AS IS" AND ADI MAKES NO WARRANTIES OR REPRESENTATIONS OF ANY KIND WITH RESPECT TO IT. ADI SPECIFICALLY DISCLAIMS ANY REPRESENTATIONS, ENDORSEMENTS, GUARANTEES, OR WARRANTIES, EXPRESS OR IMPLIED, RELATED TO THE EVALUATION BOARD INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, TITLE, FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS. IN NO EVENT WILL ADI AND ITS LICENSORS BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES RESULTING FROM CUSTOMER'S POSSESSION OR USE OF THE EVALUATION BOARD, INCLUDING BUT NOT LIMITED TO LOST PROFITS, DELAY COSTS, LABOR COSTS OR LOSS OF GOODWILL. ADI'S TOTAL LIABILITY FROM ANY AND ALL CAUSES SHALL BE LIMITED TO THE AMOUNT OF ONE HUNDRED US DOLLARS ($100.00). EXPORT. Customer agrees that it will not directly or indirectly export the Evaluation Board to another country, and that it will comply with all applicable United States federal laws and regulations relating to exports. GOVERNING LAW. This Agreement shall be governed by and construed in accordance with the substantive laws of the Commonwealth of Massachusetts (excluding conflict of law rules). Any legal action regarding this Agreement will be heard in the state or federal courts having jurisdiction in Suffolk County, Massachusetts, and Customer hereby submits to the personal jurisdiction and venue of such courts. The United Nations Convention on Contracts for the International Sale of Goods shall not apply to this Agreement and is expressly disclaimed. (c)2014 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. UG11879-0-5/14(0) Rev. 0 | Page 16 of 16 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Analog Devices Inc.: EVAL-AD5242DBZ