DEMO MANUAL DC2197A Quad 12-/10-/8-Bit PWM to VOUT DACs with 10ppm/°C Reference Description Demonstration circuit 2197A features the LTC®2645, Quad 12-/10-/8-Bit PWM to VOUT DACs with 10ppm/°C reference in a tiny 4.9mm × 4mm 16-lead MSOP package. DC2197A-A is populated with the 2.5V, 12-bit version of the LTC2645. level can be between 1.71V and 5.5V, set by a separate IOVCC pin. This device solves many of the problems associated with filtering a PWM signal to produce an analog voltage, producing a fast-settling, accurate analog voltage in response to a digital PWM input. The LTC2645 measures the period and pulse width of the Pulse Width Modulation (PWM) input and updates the voltage output DAC at each rising edge. The PWM frequency can be any frequency between 30Hz and 100kHz. The input 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 of Linear Technology Corporation. All other trademarks are the property of their respective owners. Board Photo OPTIONAL LOGIC SUPPLY CONNECTION 1.71V TO 5.5V (SEE TEXT) PWM INPUTS ANALOG OUTPUTS IOVCC 0 VCC CONNECTION 2.7V TO 5.5V (SEE TEXT) POWER-DOWN, REFERENCE CONNECTIONS (SEE TEXT) HEADERS ON REVERSE SIDE ARE FOR OPERATION WITH A LINDUINO BOARD. (SEE TEXT) Figure 1. Basic Connections dc2197afa 1 DEMO MANUAL DC2197A Quick Start Procedure Standalone Operation Linduino Operation DC2197A makes evaluation of the LTC2645 very easy. Figure 1 shows the basic connections to operate the DC2197A as a standalone board. Connect a 2.7V to 5.5V supply to the VCC turret and a GND turret. IOVCC is connected to VCC by default such that the input logic level matches the VCC supply. If a different logic level is required, move the IOVCC jumper to the EXT position and connect a supply equal to the PWM signals’ logic level to the IOVCC and GND turrets. There is no sequencing requirement between VCC and IOVCC. DC2197A is in an “Arduino Shield” form factor, compatible with Linear Technology’s DC2026 Linduino board and other Arduino Uno compatible boards. This provides a convenient way to evaluate the LTC2645 under computer control. The Linduino board has two PWM outputs with 16-bit resolution and four with 8-bit resolution. INA and INB are connected to 16-bit PWM capable outputs on digital pins 9 and 10, INC and IND are connected to 8-bit PWM capable outputs on digital pins 5 and 6; these can be remapped by removing R8 – R11 and making appropriate connections to TPA – TPD. The Linduino program (“sketch”) provides a simple terminal interface allowing voltages or codes to be entered manually. It can also be controlled by any programming language that can communicate with a USB virtual COM port (Matlab, Python, C++, C#, etc.) The program can be modified as desired to change or add functionality. Any convenient PWM source can be used. A pulse generator with a computer interface (GPIP, USB, Ethernet, etc.) can be used for characterization. In the end application, signals can originate from an FPGA, microcontroller, programmable logic controller (PLC), optocoupler, etc. Install the DC2197A onto the DC2026 as shown in Figure 2. Ensure that the IOVCC jumper is set to VCC. dc2197afa 2 DEMO MANUAL DC2197A Quick Start Procedure LINE UP AND INSERT CONNECTORS ANALOG OUTPUTS USB CONNECTION TO COMPUTER Figure 2. Linduino Connections Follow the procedure for installing drivers and sketchbook in the DC2026 Demo Manual. Upload the DC2197 program (“sketch”). Select: File → Sketchbook → Part Number → 2000 → 2600 →2645 → DC2197 Then click the “Upload” button. Open the Serial Monitor to interact with the program. dc2197afa 3 DEMO MANUAL DC2197A Quick Start Procedure Altera C5G Board Operation Altera’s C5G evaluation board for the Cyclone 5 GX FPGA has an Arduino shield port that is compatible with the DC2197A. The C5G provides 5V to the LTC2645’s VCC supply, so IOVCC must be changed to 3.3V to match the voltage of the digital signals coming from the FPGA. Remove the IOVCC jumper and solder a 100Ω resistor from the IOVCC turret post to the test point indicated in Figure 3. Make sure gaps between connectors in the upper and lower rows line up properly. The upper row (JP3 and JP4 on the C5G board) will match perfectly; JP10 will have two empty holes on the left-hand side and JP11 will have two empty holes on the right-hand side. A Quartus archive project and FPGA configuration binary file are included with the DC2197A design files. The program sends PWM signals to all four DACs. Two quadrature numerically controlled oscillators supply data to the PWM generator. While not normally intended for AC signal generation, this demonstration shows the cycle by cycle updating operation of the LTC2645. Figure 4 shows all four DAC outputs, and Figure 5 shows the details of the relationship between the PWM input and DAC output. REMOVE JUMPER 2 EMPTY LOCATIONS IOVCC TO PIN 2 2 EMPTY LOCATIONS Figure 3. Altera C5G Connections dc2197afa 4 DEMO MANUAL DC2197A Quick Start Procedure Figure 4. Altera Program Operation Figure 5. PWM Details dc2197afa 5 DEMO MANUAL DC2197A Quick Start Procedure EXTERNAL CONNECTIONS GND: Four ground turrets are provided. These are connected directly to the ground plane and are the common connection for all supplies and signals. IOVCC: I/O supply voltage that sets the high level of the PWM inputs. Connect to digital supply voltage between 1.71 and 5.5V. Often this can be connected to the same supply as the device that is providing the PWM signal (processor, FPGA, etc.). INA, INB, INC, IND: PWM Inputs. Logic high level is determined by IOVCC. VOUTA, VOUTB, VOUTC, VOUTD: DAC Voltage Outputs. VCC: Analog Supply. Connect to low noise power supply between 2.7V and 5.5V. PD: Active Low Power-Down Input. This signal may be driven externally if the PD jumper is removed. REF: Reference Output/Input. When the REFSEL jumper is set to INT, the LTC2645’s internal reference can be measured at this point. Nominal impedance is 500Ω. If it is used to drive external circuits it must be buffered appropriately. When REFSEL is set to EXT, an external reference between 1V and VCC may be connected to this point. Arduino Shield Connections (IOL1, IOH1, AD0, POWER headers installed on back side of board) – These headers mate with the DC2026 Linduino and other Arduino Uno compatible microcontroller boards. JUMPERS IOVCC: Set to VCC to connect IOVCC directly to VCC (default). No connection to the IOVCC turret is required in this case. Set to EXT if a separate supply is connected to the IOVCC turret. PD: Power Down – Set to ON to enable normal operation (default.) Set to PD to put the LTC2645 into shutdown mode. IDLSEL: Idle Mode Select Input. Determines the DAC behavior when the PWM input remains high or low for more than the Idle Mode Timeout time (50ms minimum, 70ms maximum). When set to HI-Z#/HOLD (default), a low level on a PWM input will set the DAC output to a highimpedance state. A high level will cause the DAC output to hold its last value. When set to ZS#/FS, a low level on a PWM input will set the DAC output to zero-scale, and a high level will set the DAC output to full-scale. REFSEL: Set to INT (default) to use the internal reference. Set to EXT to supply an external reference to the REF turret post. dc2197afa 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 E15 E13 E12 E11 E10 E9 E14 E8 PD ON EXT JP4 PD JP1 IOVCC VCC 1 2 3 1 2 3 VCC VCC R1 10k INT IOH1 HD1X8-100 5 IOL1 HD1X8-100 ADO HD1X6-100 POWER HD1X6-100 VCC IO2 1 2 3 VCC R7 49.9 R2 OPT VCC JP2 REFSEL EXT LINDUINO HEADERS PD GND IND INC INB INA GND IOVCC AREF 8 7 6 5 4 3 2 1 IO13 IO12 IO11 IO10 IO9 IO8 VIN 1 2 3 4 5 6 8 7 6 5 4 3 2 1 IO7 IO6 IO5 IO4 IO3 IO2 IO1 IO0 AD0 AD1 AD2 AD3 SDA SCL 1 2 3 4 5 6 RESET +3V3 4 4 NPD IND INC INB INA TPB IOVCC TPA ZS#/FS JP3 R8 49.9 1 2 3 R9 49.9 TPC VCC TPD IDLSEL HI-Z#/HOLD INB IO10 INA IO9 IND IO6 R10 49.9 INC IO5 R11 49.9 C3 0.1uF 13 REFSEL PD IND INC INB INA IOVCC REFSEL IDLSEL VCC VOUTD VOUTC VOUTB VOUTA REF * VOUTA VOUTB VOUTC VOUTD 3 14 15 REF 2 C1 10uF 6.3V 0805 U1 LTC2645 12 C2 0.1uF 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. CUSTOMER NOTICE * 2 E7 E5 E4 E3 E2 E6 E1 E16 GND VOUTD VOUTC VOUTB VOUTA GND REF VCC 1 VCC DESCRIPTION PRODUCTION REV SCALE = NONE MARK T. -BIT 12 DATE 02-11-16 1 DEMO CIRCUIT 2197A LTC2645CMS FAMILY Thursday, February 11, 2016 IC NO. SHEET 1 1 OF 1 REV. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only SUFFIX L12 MARK T. APPROVED QUAD 12/10/8-BIT PWM TO VOUT DACS DATE: N/A SIZE TECHNOLOGY U1 LTC2645-L12 TITLE: SCHEMATIC ASSY TYPE A 1. ALL RESISTORS AND CAPACITORS ARE 0603. KIM T. 2 __ ECO 1 REVISION HISTORY NOTE: UNLESS OTHERWISE SPECIFIED APPROVALS LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED APP ENG. CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. DACS C AND D CONNECTED TO 8-BIT CAPABLE PWM LINDUINO OUTPUTS DACS A AND B CONNECTED TO 16-BIT CAPABLE PWM LINDUINO OUTPUTS TEST PADS ALLOW REMAPPING LINDUINO CONNECTIONS 9 10 11 5 6 7 4 IDLSEL 3 1 VCC GND 8 GND 16 5 A B C D DEMO MANUAL DC2197A Schematic Diagram dc2197afa 7 DEMO MANUAL DC2197A 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 dc2197afa 8 Linear Technology Corporation LT 0216 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2014