1 DC934AF demo manual dc934a description ltc 2607 16-bit dual rail-to-rail dac with i 2 c interface demonstration circuit 934 a features the lt c ? 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. dc934 a has many features for evaluating the performance of the ltc2607. onboard 5v, 4.096 v, and 2.5 v precision references are provided, and the ltc2607 may be powered by the 5v reference for evaluating rail-to-rail operation. 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. p erformance s ummary 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 specifications are at t a = 25c figure 1. proper measurement equipment setup parameter condition value resolution 16 bits monotonicity v cc = 5v, v ref = 4.096v 16 bits differential nonlinearity v cc = 5v, v ref = 4.096v 1lsb integral nonlinearity v cc = 5v, v ref = 4.096v 19lsb typical load regulation v cc = v ref = 5v, mid-scale i out = 15 ma 2lsb/ma max dc crosstalk due to load current change on any other channel 3v/ma
2 DC934AF demo manual dc934a quick s tart p roce d ure 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. har d ware s etup j umpers jp1: v ref select. select 5v, 4.096 v, or 2.5 v reference. to apply an external reference through the v ref turret, remove this jumper. jp2: v cc select. v cc is taken either from the onboard 5v reference or the 5 v regulated supply from the controller board. selecting the 5 v reference for v cc and v ref allows characterization of rail to rail operation of the ltc2607. jp3: adc disable. set to on for operation with dc590 se- rial controller. when using in customers end application, the adc can be completely disabled by setting jumper to disable. for very sensitive noise measurements when using lt c supplied software, set the output voltage and stop reading voltage via the collect button on the control panel. jp5: reflo connection C either grounded or externally supplied. refer to the ltc2607 data sheet for reflo details. figure 2. software screenshot
3 DC934AF demo manual dc934a har d ware s etup jp4,6,7: i 2 c address selection. these are connected to the ca0, ca1, ca2 pins. the demo software uses the global i 2 c address, so these pins have no effect when used with the quikeval? software. they can be used in prototyping to set the i 2 c address of the ltc2607 C refer to the data sheet for the mapping of ca0,1,2 levels to i 2 c addresses. a nalo g c onnections v outa , v outb : ltc2607 outputs v ref : the v ref 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. g rounding and power connections power (v cc ): normally dc934a is powered by the dc590 controller. v cc 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. g rounding: separate power and signal grounds are pro- vided. 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. e xperiments 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. most of the data sheet specifications use a 4.096 v refer- ence, so this is the preferred reference to use for these experiments. using the 5 v regulator as the source for v cc has the limitation that v cc may be slightly lower than v ref , which may affect the full-scale error. selecting the 5 v ref- erence as the source for v cc overcomes this, however the total current that the ltc2607 can source will be limited to approximately 5ma. 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. r esolution the onboard ltc2422 adc has an input resolution of 6v. this will easily resolve a 1lsb (76 v for v ref = 5v, 62.5v for v ref = 4.096 v) 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.) i nte g ral n onlinearit y 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 calcu- lated line by more than 64 lsbs, and they will typically be within 12lsbs. l oad r e g ula tion /dc o utput i mpedance select 5 v reg for v cc source. set one of the outputs to mid-scale (code 32768). source or sink 15 ma from one of the dac outputs by pulling it to power ground or v cc with an appropriate value resistor. the voltage change
4 DC934AF demo manual dc934a p arts list should be less than 2.25 mv, 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.) z ero s cale e rror set one of the dacs to code 0. the measured output should be less than 9mv and will typically be less than 1mv. o ffset e rror set one of the dacs to code 256. the output voltage should be within 9 mv of the correct value, or v ref ? 256/65535. gain e rror set one of the dacs to code 65,535. the output voltage should be within 0.7% of v ref , and will typically be within 0.2%. dc c rosst al k set one of the dacs to mid-scale. connect a 250 resistor from the output to v cc or power ground ( to sink or source 10ma, respectively, when the 5 v reference is being used.) the other output should not change by more than 3.5v per milliamp of load current. e xperiments item qt y reference par t description manufacturer/ part number required circuit components 1 6 c1, c2, c4, c5, c6, c11 cap., x5r, 1f 10v, 0402 tdk, c1005x5r1a105mt 2 4 c3, c7, c8, c12 cap., x7r, 0.1f 16v, 0402 tdk, c1005x7r1c104mt 3 2 c9, c10 cap., npo, 100pf 50v, 0402 avx , 04025a101 jat 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 100 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 u 7 i.c., nc7wb66k8x, us8 f airchild, nc7wb66k8x
5 DC934AF demo manual dc934a 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. s c h ematic diagram 5 5 4 4 3 3 2 2 1 1 d d c c b b a a notes: unless otherwise specified 2. install shunts on jp1-jp7 pin 1 and 2. 5.0v 2.5v 4.096v vref i2c address 3. u7 multiplexes the spi and i2c busses and is for compatibility with the dc590 controller board only. 1. all resistors are in ohms, 0402. all capacitors are in microfarads, 0402. (note 3) a dc934a-ltc2607cde monday, september 26, 2005 1 1 16-bit dual rail-to-rail dac with i2c interface kim t. mark t. a schematic size date: dwg no. rev sheet of title: contract no. approvals drawn: checked: approved: engineer: designer: technology fax: (408)434-0507 milpitas, ca 95035 phone: (408)432-1900 1630 mccarthy blvd. ltc confidential-for customer use only customer notice 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. this circuit is proprietary to linear technology and supplied for use with linear technology parts. sck vouta ch1 sck cs ch0 miso mosi ca0 ca1 ca2 ldac scl sda voutb +5v v+ v+ v+ v+ vref vcc +5v vcc vref vref vcc vcc vcc vcc vcc vcc e1 vcc r10 10k jp6 ca1 c7 0.1uf,16v u4 lt1790acs6-4.096 4 2 6 1 in gnd out gnd e4 gnd r3 4.99k 1% r12 7.5k r8 10k e5 gnd jp3 adc disable enable r1 4.99k 1% c9 100pf c5 1uf,10v e2 vref c2 1uf,10v u2 ltc2422cms 5 8 1 2 3 4 7 6 9 10 zsset sdo vcc fsset ch1 ch0 cs gnd sck f0 u7 nc7wb66k8x 3 5 4 1 2 6 7 8 oe2 2a gnd 1a 1b 2b oe1 vcc jp7 ca2 e8 ldac r5 7.5k e7 voutb u3 lt1790acs6-5 4 2 6 1 in gnd out gnd c12 0.1uf,16v u1 ltc2607cde 5 8 1 2 3 4 7 6 9 10 11 12 13 sda vcc ca0 ca1 ldac scl voutb ca2 ref gnd reflo vouta gnd e9 reflo j1 hd2x7-079-molex 7 9 1 2 6 4 10 5 11 12 14 13 3 8 mosi eesda v+ 5v cs sck eevcc miso eescl eegnd nc gnd gnd gnd r7 7.5k u6 24lc025 5 8 1 2 3 4 7 6 sda vcc a0 a1 a2 vss wp scl c8 0.1uf,16v e6 vouta c11 1uf,10v c10 100pf jp5 reflo ext gnd c3 0.1uf,16v jp2 vcc 5v reg 5v ref c1 1uf,10v e3 pwr gnd u5 lt1790acs6-2.5 4 2 6 1 in gnd out gnd r9 100 c4 1uf,10v r4 100 r2 4.99k 1% r11 10k c6 1uf,10v jp4 ca0 r6 100 c b a jp1 hd2x3-079 1 3 5 6 4 2
6 DC934AF demo manual dc934a linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax : (408) 434-0507 www.linear.com ? linear technology corporation 2013 lt 0613 ? printed in usa demonstration board important notice linear technology corporation ( lt c ) 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 en g ineerin g development or evaluation purposes onl y and is not provided by lt c 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 p arty 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 lt c from all claims arising from the handling or use of the goods. due to the open construction of the product, it is the users 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. lt c assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. lt c 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 lt c applica- tion engineer. mailing address: linear technology 1630 mccarthy blvd. milpitas, ca 95035 copyright ? 2004, linear technology corporation
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