DEMO MANUAL DC416 LTC1864 16-Bit 250ksps ADC Description Demonstration circuit 416 features the LTC1864 16-bit 250ksps analog-to-digital converter. is hence much greater than what would be required in almost any practical application. This board provides a means to evaluate the performance of the LTC1864 with either the Linear Technology PScope™ data acquisition system, or with other parallel or serial data acquisition systems. The LTC1864 and its demo board are intended to be used with the PScope data acquisition system for characterization of the ADC in AC applications extending from Hz to MHz. The full power bandwidth of the LTC1864 is high enough to produce good performance in under-sampling applications, as well as applications where the signal content is below Nyquist. The board also demonstrates proper layout techniques in the circuitry surrounding the ADC and in the segmentation of the planes required to achieve full performance with the ADC. These techniques include proper grounding of the device and associated bypass capacitors, placement of the device relative to interconnection of analog and digital subsystems and signal routing in proximity to the ADC. This board performs serial to parallel conversion in a manner that is unlikely to be used in an actual implementation, but is representative of what could be implemented in an FPGA. It is expected that with this ADC, the interface will be performed serially with either programmable logic, a general-purpose processor, a DSP, or across an isolated link of one of many types. The complexity of the circuitry The board contains a bandwidth-limiting filter at the input of the ADC (C7, C8, C9, R1 and R2), as well as provision for an amplifier (U2). This bandwidth-limiting filter (–3dB at 1.5MHz) is typical of what may be required for many applications, but it is not necessarily the best for all applications. The board also incorporates an LTC1799 resistor programmable oscillator as an optional clock source. Design files for this circuit board are available at http://www.linear.com/demo/DC416 L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and PScope is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. quick start procedure Demonstration circuit 416 is easy to set up to evaluate the performance of the LTC1864. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: NOTE: The demo board is shipped with jumpers in place to allow the use of an external oscillator at 80× the sample rate. Figure 1 shows the default jumper positions. 1.Connect the parallel output J4 to either the DC718 data collection board, or to a suitable acquisition system. Pin 3 of J4 is the data strobe. 2.Observe correct polarity; Connect +8V to +15V to terminal E1. Note that –15V is only required if U2 is installed. There are two on board regulators. Both are 5V, although U1 the reference can be substituted with a lower voltage. dc416f 1 DEMO MANUAL DC416 Quick Start Procedure 3.If the intent is to do an evaluation of AC performance, connect a sinusoidal (or other) input signal to J1, or J1 and J2, with a nominal DC bias of 2.5V. If only J1 is used (single-ended operation), JP3 should be installed. This converter converts unipolar differential inputs from 0 – VREF. NOTE: The AIN inputs do not have 50Ω termination. Most generators will produce the correct signal level only if the cable is terminated at 50Ω. If you are driving this from a generator, you should use 50Ω through terminators. Take care not to overdrive the inputs if you do not use terminators. 4.Connect a 20MHz digital clock to CLKIN. With default jumpers in place, this will result in a 250ksps conversion rate. 5.Collect data via PScope for a Fourier transform into the frequency domain, or to allow data to be collected and saved to a file for subsequent import and analysis in Excel, Matlab or other analysis packages. Duplication of the FFT results shown in the data sheet requires the use of a low jitter clock and waveform generators synchronized such that the input waveform must be within a few ppm of an exact multiple of the conversion clock divided by the FFT size (termed coherent). For 250kHz sample rate and a 4096 point FFT, input frequencies should be an exact multiple of 61.035156Hz, and preferably a prime number multiple or at least an odd number multiple. The use of an even number multiple will exercise a minimal number of codes, producing poor results. IF U2 POPULATED WITH BIPOLAR AMPLIFIER – + + – SIGNAL SOURCE PARALLEL DATA COLLECTION SYSTEM IF DIFFERENTIAL SIGNAL SOURCE CLOCK SOURCE SERIAL DATA COLLECTION SYSTEM USE EITHER PARALLEL OR SERIAL DATA COLLECTION SYSTEM DC416 F01 Figure 1. Proper Measurement Equipment Setup 2 dc416f DEMO MANUAL DC416 OPERATION The conversion clock (CONV) is derived from the CLKIN connector (J3) via a programmable divider. The board is shipped with this divider set to divide by 80 (JP8 and JP9). In order for this converter to achieve its maximum throughput of 250ksps, the data transfer time must be completed in 1/fSAMPLE – TCONV, which requires that the SCLK be at 20MHz. The programmable divider can be strapped for different divide ratios if the required sample rate is less than 250ksps, allowing a greater percentage of the time available doing data transfer (divide ratio of less than 80), or if a comparable SCLK rate is used, with a lower sample rate (divide ratio greater than 80). JP8 and JP9 are set to code 16–(divide ratio/16) or 11 in the case of a divide ratio of 80. The counter circuitry gates a sequence of 16 clock pulses during CONV = 0. These can be observed on CLKOUT, or if CONV is introduced externally, (remove JP4) the clock pulses can be introduced via CLKIN (JP6 to pin 1, JP7 to pin 1 if no inversion is required). JP6 (pin 2–3) allows the use of the onboard LTC1799 oscillator. Note that this oscillator will not produce data sheet performance unless the input frequency is quite low, as the phase jitter of this oscillator will be transformed in the presence of high slew rate signals into random noise. If the amplitude of the signal falls off with increasing frequency as many natural phenomena do, this oscillator may produce acceptable results. If you are under-sampling, or operating the converter near Nyquist, it is important to have a low jitter clock source. The data output DOUT is shifted into a pair of 74HC595 serial to parallel shift registers that have output holding registers, and tri-stateable outputs. If you intend to incorporate the demo board into a prototype of a system, ENABLEDATA can be used to gate the outputs onto a 16-bit bus. Alternatively, all of the signals can be produced externally, and data can be read into a DSP via DOUT. If you elect to use the on-board timing to clock data into a slaved serial input port, you can use DOUT, CKOUT, along with CONV as a busy signal or as a means of producing a frame sync. In the event that you do not have “coherent” signal sources as described above, you can use windowing functions to reduce the “leakage” effect that occurs in the Fourier transform and get a reasonably accurate figure for SNR, THD, SINAD and the levels of the various harmonics. dc416f 3 DEMO MANUAL DC416 Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER 1 15 C1, C4-C6, C10, C11, C13-C20, C23 CAP., X7R, 0.1µF, 16V AVX, 0603YC104MAT1A 2 1 C2 CAP., X7R, 1µF, 10V, 20% AVX, 0805ZC105MAT1T 3 2 C3, C12 CAP., X5R, 10µF, 6.3V, 20%, 1206 TAIYO YUDEN JMK316BJ106MLT 4 2 C7,C9 CAP., NPO, 100PF, 50V, 1206 VITRAMON, VJ1206A101JXB 5 1 C8 CAP., NPO, 470PF, 100V,1206 AVX, 12061A471JAT 6 2 C21, C22 CAP., NPO, 47PF, 50V AVX, 06035A470MAT1A 7 9 E1-E9 TP, TURRET, .094" MILL-MAX, 2501-2 8 5 JP1, JP2, JP3, JP4, JP5 JMP, 1 × 2 .079CC COMM-CON, 2802S-02-G1 9 2 JP6, JP7 JMP, 1 × 3 .079CC COMM-CON, 2802S-03-G1 10 2 JP8, JP9 JMP, 2 × 3 .079CC COMM-CON, 2202S-06-G2 11 9 SHUNTS FOR JP1-JP9 SHUNT, .079" CENTER COMM-CON, CCIJ2MM-138G 12 3 J1-J3 CONN, BNC 50Ω, PCB-VERTICADTL CONNEX, 112404 13 1 J4 CON, HDR, .1 × .1 CNTRS, 40PIN COMMCON, 3201S-40G1 14 1 RN1 RES 2 × 4 ARRAY, CHIP, 330Ω, ISO CTS, 742-C083-331JTR-ND 15 2 R1, R2 RES, CHIP 100, 1/16W, 5%, 1206 AAC, CR18-101JM 16 2 R3, R4 RES, CHIP 2, 1/16W, 5%, 0603 AAC, CR16-2R0JM 17 2 R5, R6 RES, CHIP 402, 1/16W, 1%,0603 AAC, CR16-4020FM 18 1 R7 RES, CHIP 20k, 1/16W, 5%,0603 AAC, CR16-203JM 19 1 R8 RES, CHIP 15k, 1/16W, 5%,0603 AAC, CR16-153JM 20 1 R9 RES, CHIP 51, 1/16W, 5%,0603 AAC, CR16-510JM 21 1 R10 RES POT3321H, POT-3321H-MURATA MURATA, POT3321H-1-103 22 1 U1 IC, LT1021DCS8-5, SO8 LINEAR TECH., LT1021DCS8-5 23 0 U2 IC, OP AMP, SO8 TBD 24 1 U3 IC, LTC1864AIMS8, MSOP8 LINEAR TECH., LTC1864AIMS8 25 2 U4, U5 IC, MC74HC595ADT, TSSOP16 MOTOROLA, MC74HC595ADT 26 2 U6, U7 IC, MC74HC163AD, SO16 MOTOROLA, MC74HC163AD 27 1 U8 IC, MC74AC14DTR2, TSSOP14 ON SEMI., MC74AC14DTR2 28 1 U9 IC, MC74AC00DTR2, TSSOP14 ON SEMI., MC74AC00DTR2 29 1 U10 IC, LTC1799, SOT23-5 LINEAR TECH., LTC1799 30 1 U11 IC, LT1121CST-5, SOT223 LINEAR TECH., LT1121CST-5 31 1 U12 IC, MC74AC109DR2, SO16 ON SEMI., MC74AC109DR2 32 1 U13 IC, MC74AC32DTR2, TSSOP14 ON SEMI., MC74AC32DTR2 33 4 MTGS AT 4 CORNERS SCREW, #4-40, 1/4" ANY 34 4 MTGS AT 4 CORNERS STANDOFF, NYLON HEX #4-40 1/2" MICRO PLASTICS 14HTSP003 NOTES: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS ARE IN OHMS. 2. INSTALL SHUNTS ON JP1, JP3-JP7 PIN 1 AND 2; ON JP8 AND JP9 PIN 2 AND 4, PIN 3 AND 5. 4 dc416f A B C IN+ J1 IN- AGND -15V J2 E9 E8 +5VDIG 1 IN- 1 IN+ JP8 JP9 5 2 3 - + -15V 6 JP2 JP3 1 1 JP1 VIN 2 2 1206 R2 100 1206 R1 100 VOUT U1 LT1021-5 6 C8 470PF 1206 R3 2 C9 100PF 1206 C7 100PF 1206 C1 0.1UF +5VDIG 8 7 6 5 4 3 2 1 RCO Q0 Q1 Q2 Q3 ENT LD CLK P0 P1 P2 P3 ENP GND 74HC163AD VCC 2 1 U9A 74AC00 6 RESET U6 3 5 4 U9B 74AC00 9 10 11 12 13 14 15 16 PRE CLR CLK K J 8 7 6 5 4 3 2 1 6 4 4 3 2 1 CLK 1 2 U13A 74AC32 1 JP6 JP4 2 1 +15V 12 10 9 1 2 3 3 13 OUT U13D 74AC32 U13C 74AC32 JP7 9 C22 47PF C21 47PF 3 8 11 8 U8D 74AC14 3 1 +5VAN +5VDIG C10 0.1UF R6 402, 1% R5 402, 1% VIN U11 LT1121CST-5 +5VDIG C19 0.1UF 4 3 5 4 5 6 3 OUT 7 8 2 1 RN1 330 SET DIV LTC1799 GND V+ U10 C18 0.1UF 9 5 10 9 3 R10 10K 12 11 2 13 Q 1 R8 15K R7 20K +5VDIG PRE CLR CLK K Q 10 U12B 74AC109 14 15 16 C17 0.1UF 11 15 12 13 J C11 0.1UF 7 +5VDIG 5 6 7 8 4 LD ENT Q3 Q2 Q1 Q0 RCO VCC GND 14 +5VDIG Q Q CONV -IN LTC1864CMS8 SCLK DOUT +IN VCC C4 0.1UF VREF U3 C3 10UF 6.3V 1206 +5VAN 6 U12A 74AC109 C23 0.1UF C2 1UF 10V 0805 74HC163AD GND ENP P3 P2 P1 P0 CLK RESET U7 C16 0.1UF +5VDIG 5 1 4 3 2 U13B 74AC32 +5VDIG +5VDIG ANALOG GROUND PLANE C6 0.1UF U2 OPT +15V C5 0.1UF 7 4 D C20 0.1UF 2 1 GND 4 2 14 +15V 16 VCC GND 16 VCC GND 8 GND 2 14 7 14 7 14 7 E1 +15V 3 6 11 4 U8B 74AC14 2 U8A 74AC14 R4 2 2 KIM T. 2 DESIGNER: ENGINEER: DEREK R. APPROVED: CHECKED: DRAWN: APPROVALS CONTRACT NO. DATE: A SIZE 12 CLKIN CLKOUT DOUT R9 51 JP5 ENABLEDATA 1 8 U9C 74AC00 J3 E5 E4 E6 E7 E3 E2 13 12 CLKIN CLKOUT DOUT DGND DGND ENABLEDATA CONV +5VDIG Wednesday, February 06, 20 02 1 SHEET DC416A-2 * LTC1864CMS8 16 BIT 250 KSPS ADC DWG NO. B C D 1 OF 1 A REV 1630 McCarthy Blvd. Milpitas, CA 95035 A Phone: (408)432-1900 (408)434-0507 TECHNOLOGY Fax: LTC Confidential-For Customer Use Only 11 C15 0.1UF 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 3201S-40G1 J4 U9D 74AC00 2. INSTALL SHUNTS ON JP1,JP3-JP7 PIN 1 AND 2; ON JP8 AND JP9 PIN 2 AND 4, PIN 3 AND 5. 1. ALL RESISTORS ARE IN OHMS. U8F 74AC14 9 10 CONV 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 1 NOTES: UNLESS OTHE RWISE SPECIFIED 13 74HC595ADT GND QH SQH QG RESET QF QE QD QC SCLK LCLK OENB A QA VCC U5 QB GND QH SQH QG RESET QF QE QD QC QB SCLK LCLK OENB A QA VCC C14 0.1UF +5VDIG 74HC595ADT TITLE: 9 10 11 12 13 14 15 16 9 10 11 12 13 14 15 16 C13 0.1UF +5VDIG +5VDIG U4 U8C 74AC14 5 U8E 74AC14 10 C12 10UF 6.3V 1206 +5VDIG 14 7 14 7 5 4 3 2 5 4 3 2 4 3 2 1 6 5 6 5 2 1 4 3 14 7 7 14 7 2 1 4 2 14 7 14 7 8 14 7 1 14 3 7 14 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. 7 2 3 4 5 14 7 5 DEMO MANUAL DC416 Schematic Diagram dc416f 5 DEMO MANUAL DC416 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 6 dc416f Linear Technology Corporation LT 0713 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2013