DEMO MANUAL DC934A LTC2607 16-Bit Dual Rail-to-Rail DAC with I2C Interface Description Demonstration circuit 934A features the LTC®2607 dual 16-bit DAC. This device establishes a new board-density benchmark for 16-bit DACs and advances performance standards for output drive, load regulation, and crosstalk in single supply, voltage-output DACs. DC934A has many features for evaluating the performance of the LTC2607. Onboard 5V, 4.096V, and 2.5V precision references are provided, and the LTC2607 may be powered by the 5V reference for evaluating rail-to-rail operation. Another feature of this board is the onboard LTC2422 20‑bit ADC for monitoring DAC output voltage. The 16ppm total error of this device is adequate for taking meaningful measurements of various LTC2607 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. Figure 1. Proper Measurement Equipment Setup Performance Summary PARAMETER Specifications are at TA = 25°C 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 ±19LSB Typical Load Regulation VCC = VREF = 5V, Mid-scale IOUT = ±15 mA 2LSB/mA Max DC Crosstalk Due to Load Current Change on Any Other Channel 3µV/mA dc934af 1 DEMO MANUAL DC934A Quick Start Procedure Connect DC934A 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 DAC and reading back the resulting output voltage. Complete software documentation is available from the Help menu item, as features may be added periodically. Figure 2. Software Screenshot Hardware Setup Jumpers JP1: VREF Select. Select 5V, 4.096V, or 2.5V reference. 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 LTC2607. JP3: ADC Disable. Set to ON for operation with DC590 serial controller. When using in customer’s end application, the ADC can be completely disabled by setting jumper to DISABLE. For very sensitive noise measurements when using LTC supplied software, set the output voltage and stop reading voltage via the collect button on the control panel. JP5: REFLO connection – either grounded or externally supplied. Refer to the LTC2607 data sheet for REFLO details. dc934af 2 DEMO MANUAL DC934A Hardware Setup JP4,6,7: 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 QuikEval™ software. They can be used in prototyping to set the I2C address of the LTC2607 – refer to the data sheet for the mapping of CA0,1,2 levels to I2C addresses. Analog Connections VOUTA, VOUTB: LTC2607 Outputs VREF: The VREF turret is connected directly to the reference terminals of the LTC2607 and LTC2422 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 JP1. Grounding and Power Connections Power (VCC): Normally DC934A 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. Experiments The following experiments are intended to demonstrate some of the outstanding features of the LTC2607. All can be performed using the onboard LTC2422 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. 62.5μV for VREF = 4.096V) change in the LTC2607 output. Set the DAC output 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.) 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 LTC2607 can source will be limited to approximately 5mA. Integral Nonlinearity 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 LTC2422 ADC has an input resolution of 6μV. This will easily resolve a 1LSB (76μV for VREF = 5V, A rough measurement of INL can be taken using the onboard ADC. Measure one of the LTC2607 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. Load Regulation/DC Output Impedance Select 5V REG 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 dc934af 3 DEMO MANUAL DC934A Experiments should be less than 2.25mV, corresponding to an output impedance of 0.15Ω. Output impedance is typically less than 0.030Ω. (measure DAC voltage at the output pin if using a voltmeter.) Gain Error Zero Scale Error DC Crosstalk 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 9mV of the correct value, or VREF • 256/65535. 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%. Set one of the DACs to mid-scale. Connect a 250Ω resistor from the output to VCC or power ground (to sink or source 10mA, respectively, when the 5V reference is being used.) The other output should not change by more than 3.5μV per milliamp of load current. Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 6 C1, C2, C4, C5, C6, C11 CAP., X5R, 1µF 10V, 0402 TDK, C1005X5R1A105MT 2 4 C3, C7, C8, C12 CAP., X7R, 0.1µF 16V, 0402 TDK, C1005X7R1C104MT 3 2 C9, C10 CAP., NPO, 100pF 50V, 0402 AVX, 04025A101JAT 4 9 E1-E9 TESTPOINT, TURRET, 0.064" MILL-MAX, 2308-2 5 1 JP1 JMP, 2X3, 0.079CC SAMTEC, TMM-103-02-L-D 6 6 JP2-JP7 JMP, 3 PIN 1 ROW 0.079CC SAMTEC, TMM-103-02-L-S 7 7 SHUNTS FOR JP1-JP7 PIN 1 AND 2 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G 8 1 J1 HEADER, 2X7 PIN, 0.079CC MOLEX, 87331-1420 9 3 R1, R2, R3 RES., CHIP 4.99k 1/16W 1%, 0402 AAC, CR05-4991FM 10 3 R4, R6, R9 RES., CHIP 100Ω 1/16W 5%, 0402 VISHAY, CRCW0402101J 11 3 R5, R7, R12 RES., CHIP 7.5k 1/16W 5%, 0402 AAC, CR05-752JM 12 3 R8, R10, R11 RES., CHIP 10k 1/16W 5%, 0402 AAC, CR05-103JM 13 1 U1 I.C., LTC2607CDE, DFN12DE LINEAR TECH., LTC2607CDE 14 1 U2 I.C., LTC2422CMS, MSOP10 LINEAR TECH., LTC2422CMS 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, 24LC025-I/ST 19 1 U7 I.C., NC7WB66K8X, US8 FAIRCHILD, NC7WB66K8X dc934af 4 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 1 EEVCC NC EEGND EESCL EESDA MISO MOSI SCK CS C1 1UF,10V LDAC E8 JP7 CA2 JP6 CA1 JP4 VCC CA0 +5V 2 1 CA2 SDA C3 0.1UF,16V SCL LDAC CA1 CA0 U1 LTC2607CDE 3 OE2 4 GND 1 1A 2 1B VOUTB VCC REF GND REFLO 5 4 A1 A0 2 1 7 8 9 10 11 12 E9 REFLO C12 0.1UF,16V C10 100PF R5 7.5K C9 100PF R7 7.5K CH0 CH1 VREF 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. DRAWN: KIM T. DESIGNER: OUT OUT 1 5V REG C B A 6 4 2 JP3 ADC E7 E6 ENABLE GND GND VREF VCC VOUTB VOUTA E5 E4 E2 E1 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only VCC VREF DISABLE 5V REF JP1 VREF JP2 VCC HD2X3-079 4.096V 3 2.5V 5 5.0V R8 R9 10K 100 SCK C6 1UF,10V C5 1UF,10V C4 1UF,10V TECHNOLOGY SCHEMATIC CS 7 GND 6 SDO 8 9 10 6 6 6 VCC +5V 1 2 DATE: A SIZE 1 SHEET 1 DC934A-LTC2607CDE Monday, September 26, 2005 DWG NO. OF 1 A REV 16-BIT DUAL RAIL-TO-RAIL DAC WITH I2C INTERFACE TITLE: 5 ZSSET 3 CH1 4 CH0 SCK F0 U2 LTC2422CMS IN U5 LT1790ACS6-2.5 IN 1 VCC 2 FSSET ENGINEER: MARK T. APPROVED: CHECKED: OUT U4 LT1790ACS6-4.096 APPROVALS R4 100 R6 100 2 U3 LT1790ACS6-5 IN CONTRACT NO. VOUTB VOUTA C11 1UF,10V 4 4 4 VCC C8 0.1UF,16V V+ V+ V+ CUSTOMER NOTICE 3 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. VCC C7 0.1UF,16V VREF REFLO EXT JP5 GND R11 10K VCC 6 SCL A2 3 5 SDA VSS 4 8 VCC 7 WP U6 24LC025 3. U7 MULTIPLEXES THE SPI AND I2C BUSSES AND IS FOR COMPATIBILITY WITH THE DC590 CONTROLLER BOARD ONLY. 2. INSTALL SHUNTS ON JP1-JP7 PIN 1 AND 2. 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS, 0402. 5 6 7 8 VOUTA 2A 2B OE1 VCC U7 (NOTE 3) NC7WB66K8X SDA 6 CA2 5 LDAC 3 SCL 4 CA1 CA0 R10 10K VCC R1 R2 R3 4.99K 4.99K 4.99K 1% 1% 1% C2 1UF,10V 4 NOTES: UNLESS OTHERWISE SPECIFIED R12 7.5K VCC I2C ADDRESS E3 PWR GND 14 12 11 9 10 MOSI 7 MISO 5 SCK CS 6 4 5V 2 V+ J1 HD2X7-079-MOLEX GND 3 GND 8 GND 13 GND 1 GND 1 GND 1 V+ GND 13 GND 2 GND 2 GND 2 5 A B C D DEMO MANUAL DC934A Schematic Diagram dc934af 5 DEMO MANUAL DC934A 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 © 2004, Linear Technology Corporation dc934af 6 Linear Technology Corporation LT 0613 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2013