DESCRIPTION Demonstration circuit 8A features the LTC 98, a precision reference that can be programmed through an easy-to-use I C interface. While external pins or internal register bits select the central output voltage for sixteen values from V to V, an 8-bit DAC adjusts this mid-scale output with a selectable, relative ±% or ±0% range. DC8A is a part of Linear Technology s QuikEval family of demonstration boards. It is designed to allow easy evaluation of the LTC98 and may be connected directly to the target application s reference inputs while using the DC90 USB Serial Controller board and supplied software to measure performance. DEMO MANUAL DC8A LTC98: I C Programmable Precision Reference with EEPROM Ground turrets are provided to allow for proper grounding to prototype circuitry. After evaluating with Linear Technology s software, the digital signals can be connected to the end application s processor/controller for development of the serial interface. Design files for this circuit board are available at www. linear.com/demo. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. RIBBON CABLE TO DC90 CONTROLLER Figure. Proper Measurement Equipment Setup dc8af
DEMO MANUAL DC8A QUICK START PROCEDURE Connect DC8A to a DC90 USB Serial Controller using the supplied conductor ribbon cable. Connect DC90 to host PC with a standard USB A/B cable. Run the evaluation software supplied with DC90 or downloaded from http://www.linear.com/software. The correct program will be loaded automatically. Click the COLLECT button to start reading the input voltage. Details on software features are documented in the control panel s help menu. Figure. Software Screenshot dc8af
DEMO MANUAL DC8A HARDWARE SET-UP CONNECTION TO DC90 SERIAL CONTROLLER J is the power and digital interface connector. Connect to DC90 serial controller with supplied conductor ribbon cable. JUMPER SETTINGS AD0, AD Set the I C address. Any changes made on the jumpers should also be made in software in order for digital communication to work properly. VP0, VP, VP Voltage Programming Bits. V CC Either V or 0V, this sets the V IN of the LTC98. Table. LTC98 Voltage Selection (L = Low, H = High, F = Float) INTERNAL REGISTER BIT-FIELD, PIN SELECTION vsel[:0], SELECTION V OUT (V) V P V P V PO [] [] [] [0] 0. L L L 0 0 0 0 0. L L F 0 0 0 0.8 L L H 0 0 0 L F L 0 0.0 L F F 0 0 0. L F H 0 0. L H L 0 0. L H F 0.8 L H H 0 0 0 H L L 0 0.08 H L F 0 0. H L H 0 H F L 0 0. H F F 0.09 H F H 0 H H L vsel[:0]* H H F H H H *Output voltage is selected by the internal CONFIG register bit-field, vsel[:0], when (V P, V P, V P0 ) = (H, H, F) or (H, H, H). dc8af
DEMO MANUAL DC8A HARDWARE SETUP Analog Connections Analog signal connections are made via the row of turret posts along the edge of the board. : This turret is connected directly to the internal ground planes. V IN : This turret is connected to either the V or 0V output of the DC90 depending on the V CC Jumper setting. An external supply can be applied to this point if the V CC jumper is removed. STAT: The STAT turret is connected directly to the STAT pin of the DAC. This is not implemented in the QuikEval software. SHDN: Device Shutdown. The internal regulated supply shuts down when the SHDN is pulled low. TEMP: Voltage V TEMP, indicates internal temperature of the die. T = C + V TEMP.8V.98mV / C V OUT /V OUT_SENSE : Voltage Output of the LTC98. This can be set either by the QuikEval software or the Voltage Programming bits. V OUT_SENSE is Kelvin connected near the V OUT pin. dc8af
DEMO MANUAL DC8A SCHEMATIC DIAGRAM T V+ D D J HDRX7-079-MOLEX V+ +V +V E SCL C C R R JP JP VP VP JP R U LC0ST VP0.99K.99K.99K E8 SCL 0 0 0 WP 7 E B B 0.0 VIA TESTPOINTS T LTC98ACUFD R 0K JP AD0 0 0 JP AD.V JP VCC V+ V +V VUNREG V CS SCK/SCL MOSI/SDA MISO EEVCC EESDA EESCL EE NC 9 7 0 0 U LTC98ACUFD C uf 8 7 8 9 SCL SDA STAT SHDN VP0 TEMP VOUT DNC R AD0 AD T VP VP E C 0.uF E7 SDA SHDN E R 0K C7 0.uF R7 C.7uF C.7uF E E0 E TEMP VOUT_SENSE Array EEPROM 8 SDA VCC A A A0 STAT E E VOUT LINEAR TECHNOLOGY CORPORATION 0 McCARTHY BLVD. MILPITAS, CA. 90 08--900 08--007 FAX A A Title IC Programmable Reference Size Document Number Rev DC8A LTC98ACUFD Monday, January, 009 Date: Sheet of 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. dc8af
DEMO MANUAL DC8A 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 0 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 0 McCarthy Blvd. Milpitas, CA 90 Copyright 00, Linear Technology Corporation LT 00 PRINTED IN USA Linear Technology Corporation 0 McCarthy Blvd., Milpitas, CA 90-77 (08) -900 FAX: (08) -007 www.linear.com LINEAR TECHNOLOGY CORPORATION 00 dc8af