DEMO MANUAL DC936A LTC2609 Quad 16-Bit Rail-to-Rail DAC with I2C Interface Description Demonstration circuit 936A features the LTC(R)2609 Quad 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. DC936A has many features for evaluating the performance of the LTC2609. Onboard 5V, 4.096V, and 2.5V precision references are provided. The LTC2609 features separate reference inputs for each DAC, and any of the onboard references can be used for any of the reference inputs. 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 LTC2609 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 4V/mA dc936af 1 DEMO MANUAL DC936A Quick Start Procedure Figure 1. Proper Measurement Equipment Setup dc936af 2 DEMO MANUAL DC936A Quick Start Procedure Connect DC936A 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. Evaluation Software dc936af 3 DEMO MANUAL DC936A Hardware Setup Jumpers Analog Connections JP1 - REFLO Selection. Either tied to ground or supplied externally to the REFLO turret post. DAC Outputs - The four DAC outputs from the LTC2609 are brought out to turrets labeled DAC A through DAC D. These may be connected to external instruments or other circuitry. JP2 - 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. JP7 - VREF Select for ADC. This selects which onboard reference is used for the LTC2428 ADC. If all DAC references are set to the same voltage, set the ADC reference to the same voltage. If different DAC reference voltages are used, set the ADC reference to the highest DAC reference voltage. JP3, JP4, JP5, JP6 - Select reference for DAC A, B, C, and D, respectively. Onboard references are 2.5V, 4.096V, and 5.0V. Remove jumper entirely to apply an external reference. JP11 - 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 LTC2609. JP8, JP9, JP10 - 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 LTC2607 - refer to the data sheet for the mapping of CA0, 1, 2 levels to I2C addresses. DAC outputs are not in alphabetical order on the circuit board. DAC References - The REFA, REFB, REFC, and REFD turrets are connected directly to the reference terminals of the onboard references. 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 the associated reference selection jumper. REFLO - This is connected to the LTC2609 REFLO pin and can be used to raise the zero-code output of all of the DACs above ground potential. This is normally set to ground, but may be raised up to 1V above ground. Refer to the LTC2609 data sheet for details. Ground Connections Grounding - Separate power and signal grounds are provided. Any large currents drawn from the DAC outputs should be returned to the power ground turret closest to Pin 1 on the 14-pin header. 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. dc936af 4 DEMO MANUAL DC936A Experiments The following experiments are intended to demonstrate some of the outstanding features of the LTC2609. 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 5 volt reference has the limitation that VCC may be slightly lower than VREF, which may affect the full scale error. 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 LTC2609 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 LTC2609 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. dc936af 5 DEMO MANUAL DC936A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER 1 8 C1, C4, C5, C6, C8, C10, C13, C14 CAP., X7R, 0.1F 16V,0402 TDK, C1005X7R1C104M 2 5 C2, C7, C9, C11, C12 CAP., X5R, 1.0F 10V, 0402 TDK, C1005X5R1A105MT 3 1 C3 CAP., NPO, 100pF 50V, 0402 AVX, 04025A101MAT 4 14 E1-E14 TESTPOINT, TURRET, 0.064" MILL-MAX, 2308-2 5 6 JP1, JP2, JP8, JP9, JP10, JP11 JMP, 3 PIN 1 ROW .079CC SAMTEC TMM-103-02-L-S 6 5 JP3, JP4, JP5, JP6, JP7 HEADER, 2x3 PIN, 0.079CC SAMTEC TMM-103-02-L-D 7 11 JP1-JP11 PIN 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%, 0402 AAC, CR05-4991FM 10 2 R4, R9 RES., CHIP 10k 1/16W 5%, 0402 PANASONIC, ERJ2GEJ103X 11 3 R5, R6, R7 RES., CHIP, 7.5k, 5%, 0402 AAC, CR05-752JM 12 1 R8 RES., CHIP, 22, 5%, 0402 AAC, CR05-220JM 13 1 U1 I.C., LTC2609CGN, SSOP16GN LINEAR TECH., LTC2609CGN 14 1 U2 I.C., 24LC025, TSSOP8 MICROCHIP, 24LC025-I /ST 15 1 U3 I.C., LTC2428CG, SSOP28G LINEAR TECH., LTC2428CG 16 1 U4 I.C., LT1790ACS6-5.0, SOT23-6 LINEAR TECH., LT1790ACS6-5 17 1 U5 I.C., LT1790ACS6-4.096, SOT23-6 LINEAR TECH., LT1790ACS6-4.096 18 1 U6 I.C., LT1790ACS6-2.5, SOT23-6 LINEAR TECH., LT1790ACS6-2.5 19 1 U7 I.C., NC7WB66K8X, US8 FAIRCHILD, NC7WB66K8X dc936af 6 A B C D MOSI 7 MISO 5 CS 6 SCK 4 V+ 1 5V 2 V+ V+ V+ VOUT 6 NC 5 4 VIN 3 NC VOUT 6 NC 5 U5 LT1790ACS6-4.096 VOUT 6 NC 5 U6 LT1790ACS6-2.5 4 VIN C10 3 NC 0.1UF C8 0.1UF MISO MOSI SCK CS C12 1.0UF,10V U4 LT1790ACS6-5 4 VIN 3 NC E13 E12 C6 0.1UF PWR GND VCC VCC EESCL 11 EEGND 12 NC 14 EEVCC 10 EESDA 9 GND 3 GND 8 GND 13 5 VCC R1 4.99K 1% C2 1.0UF,10V JP11 VCC 2B 6 2A 5 5V REF 5V REG 3 OE2 4 GND VCC 8 OE1 7 A0 1 A1 2 R9 10K VCC C14 0.1UF 6 SCL A2 3 5 SDA VSS 4 8 VCC 7 WP U2 24LC025 SCL SDA CA2 E1 8 SCL 7 CA2 9 SDA 11 CA0 10 CA1 1 0 REF LO SCL SDA CA0 CA1 JP8 CA2 4 3 VCC C1 0.1UF 1 0 VCC JP10 CA0 VOUT D 14 REF D 15 VOUT C 13 REF C 12 VOUT B 5 REF B 6 VOUT A 4 REF A 3 U1 LTC2609CGN JP9 CA1 I2C ADDRESS 3. U7 MULTIPLEXES THE SPI AND I2C BUSSES AND IS OR COMPATIBILITY WITH THE DC590 CONTROLLER BOARD ONLY. 2. INSTALL SHUNTS ON JP1-JP11 PIN 1 AND 2. 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS, 0402. NOTES: UNLESS OTHERWISE SPECIFIED C11 1.0UF,10V 2.5VREF C9 1.0UF,10V 4.096VREF C7 1.0UF,10V C13 0.1UF U7 (NOTE 3) NC7WB66K8X R3 4.99K 1% 1 1A 2 1B R2 4.99K 1% R4 10K 5VREF VCC +5V +5V 4 VCC 16 1 0 A B C 1 3 5 REFA JP3 5 ZSSET 15 CH6* 17 CH7* 13 CH4* 14 CH5* THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 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. 3 5 3 1 C B A REFB JP4 C3 100PF 6 4 2 2 4-/8-CHANNEL MUX U3 LTC2428CG 11 CH2 12 CH3 6 4 2 9 CH0 10 CH1 CUSTOMER NOTICE GND JP1 REF LO EXT REF LO 2 REFLO GND 1 V+ GND KIM T. DESIGNER: 2 ENGINEER: MARK T. APPROVED: CHECKED: DRAWN: APPROVALS CONTRACT NO. R5 7.5K 5 3 1 DATE: A SIZE TITLE: + C B A 6 4 2 B C 5 CLK 19 DIN 21 E7 E8 E9 REFC VOUTD REFD R7 7.5K MISO MOSI SCK R6 7.5K CS DISABLE ENABLE E11 1 SHEET 1 DC936A-1 * LTC2609CGN Tuesday, October 11, 2005 MISO MOSI SCK CS GND GND REFD VOUTD REFC VOUTC REFB VOUTB QUAD 16-BIT DAC WITH I2C DWG NO. SCHEMATIC TECHNOLOGY E6 VOUTC REFA VOUTA 2.5VREF 4.096VREF OF 1 A-1 REV 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only FO 26 SD0 24 CSADC 23 CSMUX 20 SCK 25 E5 REFB VCC E4 5.0 4.096 2.5 E14 VREF 5VREF E10 E3 6 VOUTB JP2 ADC C 4 2 E2 5 6 B A VREF REFA 3 4 ADC REF JP7 1 VOUTA 1 2 VCC C5 0.1UF A 3 REFD JP6 1 LTC2424/LTC2428 - 20-BIT ADC R8 22 VREF C4 0.1UF REFC JP5 ADCIN 4 J1 HD2X7-079-MOLEX GND 1 GND 2 GND 1 GND 2 GND 1 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. 2 GND 1 MUXOUT 7 GND 6 GND 16 GND 18 FSSET 3 GND 27 GND 28 GND 22 VCC 2 VCC 8 5 A B C D DEMO MANUAL DC936A Schematic Diagram dc936af 7 DEMO MANUAL DC936A 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 dc936af 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