DEMO MANUAL DC935A LTC2605 16-Bit Octal Rail-to-Rail DAC with I2C Interface Description Demonstration circuit 935A features the LTC(R)2605 octal 16-bit DAC. This device establishes a new board-density benchmark for 16-bit DACs and advances performance standards for output drive, crosstalk and load regulation in single supply, voltage-output multiple DACs. DC935A has many features for evaluating the performance of the LTC2605. Onboard 5V and 4.096V precision references are provided, and the LTC2605 may be powered by the 5V reference for evaluating rail-to-rail operation. Performance Summary PARAMETER Another feature of this board is the onboard LTC2428 20-bit ADC for monitoring DAC output voltage. The 16ppm total error of this device is adequate for taking meaningful measurements of various LTC2605 parameters. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and QuikEval is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Specifications are at TA = 25C CONDITION Resolution VALUE 16 Bits Monotonicity VCC = 5V, VREF = 4.096V 16 Bits Differential Nonlinearity VCC = 5V, VREF = 4.096V 1LSB Integral Nonlinearity VCC = 5V, VREF = 4.096V 18LSB Typical Load Regulation VCC = VREF = 5V, Mid-Scale IOUT = 15mA 2LSB/mA Max DC Crosstalk Due to Load Current Change on Any Other Channel 3.5V/mA dc935af 1 DEMO MANUAL DC935A Quick Start Procedure Figure 1. Proper Measurement Equipment Setup dc935af 2 DEMO MANUAL DC935A Quick Start Procedure Connect DC935A to a DC590 USB serial controller using the supplied 14-conductor ribbon cable. Connect DC590 to a host PC with a standard USB A/B cable. Run the evaluation software supplied with DC590 or download it from www.linear.com/software. The correct control panel will be loaded automatically. Click the COLLECT button to begin outputting codes to the DACs and reading back the resulting output voltage for each DAC. Complete software documentation is available from the Help menu item, as features may be added periodically. Figure 2. DC935A QuikEval Screen Shot dc935af 3 DEMO MANUAL DC935A Hardware Setup Jumpers JP1 - VREF Select either a 5V, 4.096V or 2.5V precision reference can be selected. To apply an external reference through the VREF Turret, remove this jumper. JP2 - VCC Select. VCC is taken either from the onboard 5V reference or the 5V regulated supply from the controller board. Selecting the 5V reference for VCC and VREF allows characterization of rail to rail operation of the LTC2605. JP3 - ADC Disable. Set to ON for normal operation with the onboard ADC enabled. For very sensitive noise measurements, the ADC may be disabled. The software will then display a positive full-scale reading. JP4, JP5, JP6 - I2C Address Selection. These are connected to the CA0, CA1, CA2 pins. The demo software uses the global I2C address, so these pins have no effect when used with the QuikEvalTM software. They can be used in prototyping to set the I2C address of the LTC2605 - refer to the data sheet for the mapping of CA0, 1, 2 levels to I2C addresses. Analog Connections DAC Outputs - The eight DAC outputs from the LTC2605 are brought out to turrets labeled DAC A through DAC H. These may be connected to external instruments or other circuitry. DAC outputs are not in alphabetical order on the circuit board. VREF - The VREF turret is connected directly to the reference terminals of the LTC2605 and LTC2428 ADC. When one of the onboard references is being used, the reference voltage may be monitored at this point. An external reference may also be applied to this turret after removing JP2. Grounding and Power Connections Power (VCC) - Normally DC935A is powered by the DC590 controller. VCC can be supplied to this turret, however the power supply on DC590 must be disabled. Refer to DC590 quick start guide for more details on this mode of operation. Grounding - Separate power and signal grounds are provided. Any large currents drawn from the DAC outputs should be returned to power ground. Also, if an external power supply is connected, power ground should be used. Signal ground is connected to the exposed ground planes at the top and bottom edges of the board, and to the two turrets labeled "GND." Use signal ground as the reference point for measurements and connections to external circuits. dc935af 4 DEMO MANUAL DC935A Experiments The following experiments are intended to demonstrate some of the outstanding features of the LTC2605. All can be performed using the onboard LTC2428 to monitor the DAC output voltage. The indicated output voltage will typically agree with an HP3458A voltmeter to 5 digits. If a DAC will be sinking or sourcing a significant current, then the output voltage should be measured as close to the DAC as possible. Most of the data sheet specifications use a 4.096V reference, so this is the preferred reference to use for these experiments. Using the 5V regulator as the source for VCC has the limitation that VCC may be slightly lower than VREF, which may affect the full-scale error. Selecting the 5V reference as the source for VCC overcomes this, however the total current that the LTC2605 can source will be limited to approximately 5mA. Using an external power supply is highly recommended for these experiments, especially those that draw significant current. Refer to the DC590 quick start guide for details. Resolution The onboard LTC2428 ADC has an input resolution of 6V. This will easily resolve a 1LSB (76V for VREF = 5V, 62.5V for VREF = 4.096V) change in the LTC2605 output. Set one of the DAC channels to a voltage close to mid-scale. Select the FINE slider on the control panel with the mouse and use the right and left arrow keys to step the output by single LSBs. The change should be clearly visible in the output graph. (It may be necessary to wait for the graph to clear if a large step has just occurred. This can be sped up by disabling all other DAC channels in the software by un-checking them.) Load Regulation/DC Output Impedance Select "Regulator" for VCC source. Set one of the outputs to mid-scale (code 32768). Source or sink 15mA from one of the DAC outputs by pulling it to power ground or VCC with an appropriate value resistor. The voltage change should be less than 2.25mV, corresponding to an output impedance of 0.15. Output impedance is typically less than 0.030. (Measure DAC voltage at the output pin if using a voltmeter.) Zero Scale Error Set one of the DACs to code 0. The measured output should be less than 9mV and will typically be less than 1mV. Offset Error Set one of the DACs to code 256. The output voltage should be within 1mV of the correct value, or VREF * 256/65535. Gain Error Set one of the DACs to code 65,535. The output voltage should be within 0.7% of VREF, and will typically be within 0.2%. DC Crosstalk Set all DACs to mid-scale. Connect a 250 resistor from one output to VCC or power ground (to sink or source 10mA, respectively, when the 5V reference is being used.) A given output should not change by more than 3.5V per milliamp of output current in all other DACs combined. Integral Nonlinearity A rough measurement of INL can be taken using the onboard ADC. Measure one of the LTC2605 outputs at code 256 and 65,535 and calculate the slope and intercept using a spreadsheet. Next, take several readings at intermediate points. The readings should not deviate from the calculated line by more than 64LSBs, and they will typically be within 12LSBs. dc935af 5 DEMO MANUAL DC935A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER 1 6 C1, C2, C4-C7 CAP., X5R, 1F 10V, 0402 TDK, C1005X5R1A105MT 2 6 C3, C8, C9, C10, C12, C13 CAP., X7R, 0.1F 16V, 0402 TDK, C1005X7R1C104MT 3 1 C11 CAP., NPO, 100pF 50V, 0402 AVX, 04025A101KAT 4 13 E1-E13 TESTPOINT, TURRET, 0.064" MILL-MAX, 2308-2 5 1 JP1 JMP, 2x3, .079CC COMM CON, 2202S-06G2 6 5 JP2, JP3, JP4, JP5, JP6 JMP, 3 PIN 1 ROW .079CC SAMTEC, TMM-103-02-L-S 7 6 SHUNTS FOR JP1 (3 AND 4), JP2-JP6 (1 AND 2) SHUNT, .079" CENTER SAMTEC, 2SN-BK-G 8 1 J1 HEADER, 2x7 PIN, 0.079CC MOLEX, 87831-1420 9 3 R1, R2, R3 RES., CHIP 4.99k 1/16W 1%, 0402 AAC, CR05-4991FM 10 2 R4, R5 RES., CHIP 10k 1/16W 5%, 0402 AAC, CR05-103JM 11 3 R6, R8, R9 RES., CHIP 7.5k 1/16W 1%, 0402 AAC, CR05-7501FM 12 1 R7 RES., CHIP 22 1/16W 5%, 0402 AAC, CR05-220JM 13 1 U1 I.C., LTC2605CGN, SSOP16GN LINEAR TECH., LTC2605CGN 14 1 U2 I.C., LTC2428CG, SSOP28G LINEAR TECH., LTC2428CG 15 1 U3 I.C., LT1790ACS6-5, SOT23-6 LINEAR TECH., LT1790ACS6-5 16 1 U4 I.C., LT1790ACS6-4.096, SOT23-6 LINEAR TECH., LT1790ACS6-4.096 17 1 U5 I.C., LT1790ACS6-2.5, SOT23-6 LINEAR TECH., LT1790ACS6-2.5 18 1 U6 I.C., 24LC025, TSSOP8 MICROCHIP, 24LC025I/ST 19 1 U7 I.C., NC7WB66K8X, US8 FAIRCHILD, NC7WB66K8X dc935af 6 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. A B C D MOSI 7 MISO 5 CS 6 SCK 4 NC 14 EESCL 11 EEGND 12 EEVCC 10 EESDA 9 GND E3 JP6 CA2 JP5 CA1 VCC JP4 CA0 0 0 0 1 1 1 SCL 5 SDA R4 10K 9 SDA 8 SCL SDA SCL 7 CA2 11 CA0 10 CA1 6 REF 2B 6 2A 5 VCC 8 OE1 7 VOUT G 14 VOUT H 15 VOUT E 12 VOUT F 13 VOUT C 4 VOUT D 5 VOUT A 2 VOUT B 3 C8 0.1UF,16V 4 3. U7 MULTIPLEXES THE SPI AND I2C BUSSES AND IS FOR COMPATIBILITY WITH THE DC590 CONTROLLER BOARD ONLY. 2. INSTALL SHUNTS ON JP1-JP8 PIN 1 AND 2. 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS, 0402. DACH DACG DACF DACE DACD DACC DACB DACA R5 10K VCC 6 SCL 5 SDA VSS 4 A0 1 A1 2 A2 3 U6 24LC025 8 VCC 7 WP U1 LTC2605CGN VCC C9 0.1UF,16V 3 OE2 4 GND 1 1A 2 1B CA2 CA1 CA0 C3 0.1UF,16V U7 (NOTE 3) NC7WB66K8X R3 4.99K 1% VREF R2 4.99K 1% C10 0.1UF,16V R1 4.99K 1% MISO MOSI SCK CS C2 1UF,10V VCC +5V NOTES: UNLESS OTHERWISE SPECIFIED MISO MOSI SCK CS I2C ADDRESS PWR GND 3 GND 8 GND 13 C11 R6 100PF 7.5K 4-/8-CHANNEL MUX 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. APPROVALS 2 DESIGNER: KIM T. ENGINEER: MARK T. APPROVED: CHECKED: DRAWN: CONTRACT NO. OUT 6 SCK 25 CLK 19 SCHEMATIC C B A 1 6 4 2 5V REF 5V REG JP1 VREF JP2 VCC EN DIS R8 7.5K CS JP3 ADC HD2X3-079 VREF E2 E1 VREF VCC 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only R9 7.5K MISO MOSI SCK VCC TECHNOLOGY FO 26 DIN 21 SDO 24 CSADC 23 CSMUX 20 1 4.096V 3 2.5V 5 5.0V VCC +5V DATE: A SIZE 1 SHEET 1 DC935A-LTC2605CGN Monday, September 26, 2005 DWG NO. OF 1 A REV 16-BIT OCTAL RAIL-TO-RAIL DAC WITH I2C INTERFACE TITLE: C6 1UF,10V C5 1UF,10V C4 1UF,10V VCC C13 0.1UF,16V LTC2424/LTC2428 - 20-BIT ADC + R7 22 C12 VREF 0.1UF,16V * NC FOR LTC2824CGN 5 ZSSET 15 CH6* 17 CH7* 13 CH4* 14 CH5* 11 CH2 12 CH3 U2 LTC2428CG 9 CH0 10 CH1 4 IN C7 1UF,10V CUSTOMER NOTICE DAC H DAC G DAC F DAC E DAC D DAC C DAC B DAC A GND GND OUT 6 U5 LT1790ACS6-2.5 4 IN U4 LT1790ACS6-4.096 OUT 6 U3 LT1790ACS6-5 4 IN LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. E13 E12 E11 E10 E9 E8 E7 E6 E5 E4 V+ V+ V+ 2 GND V+ 1 5V 2 3 1 GND 16 4 1 GND 22 C1 1UF,10V GND 5 GND 27 V+ VCC 16 GND 1 GND 6 GND 1 GND 2 GND 1 GND 2 GND 2 MUXOUT 7 ADCIN 4 GND 18 FSSET 3 VCC 2 VCC 8 GND 28 J1 HD2X7-079-MOLEX A B C D DEMO MANUAL DC935A Schematic Diagram dc935af 7 DEMO MANUAL DC935A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user's responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright (c) 2004, Linear Technology Corporation dc935af 8 Linear Technology Corporation LT 0513 * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 2013