DC812A - Demo Manual

DEMO MANUAL DC812A
LTC2606
16-Bit Rail-to-Rail VOUT DAC
with I2C Interface
Description
Demonstration circuit 812A features the LTC®2606
16-bit DAC with I2C interface. This device establishes a
new board-density benchmark for 16-bit DACs and advances performance standards for output drive and load
regulation in single-supply, voltage output DACs.
DC812A has many features for evaluating the performance
of the LTC2606. Onboard 5V, 4.096V and 2.5V precision
references are provided, and the LTC2606 may be powered
by the 5V reference for evaluating rail-to-rail operation.
Performance Summary
SYMBOL
Another feature of this board is the onboard LTC2421 20-bit
ADC for monitoring DAC output voltage. The 16ppm total
error of this device is adequate for taking meaningful
measurements of various LTC2606 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 = 25°C
PARAMETER
CONDITIONS
Resolution
16 Bits
Monotonicity
VCC = 5V, VREF = 4.096V
16 Bits
Differential Nonlinearity
VCC = 5V, VREF = 4.096V
±1 LSB
Integral Nonlinearity
VCC = 5V, VREF = 4.096V
±12 LSB Typical
Load Regulation
VCC = VREF = 5V, Mid-Scale, IOUT = ±15mA
2 LSB/mA Max
Board Photo
RIBBON CABLE
–
+
TO
DC590
+
TO DAC OUTPUT
FOR LOAD
REGULATION
EXPERIMENTS
–
VOLTMETER
REFERENCE MONITOR
(OR EXTERNAL
REFERENCE SOURCE;
SEE HARDWARE SET-UP)
dc812a F01
Figure 1. DC812A Connection Diagram
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DEMO MANUAL DC812A
Quick Start Procedure
1. Connect the DC812A to a DC590 USB serial controller
using the supplied 14-conductor ribbon cable.
4. Click the Collect button to begin outputting codes to
the DAC and reading back the resulting output voltage.
2. Connect the DC590 to a host PC with a standard USB
A/B cable.
Complete software documentation is available from the
Help menu item, as features may be added periodically.
3. Run the QuikEval™ evaluation software supplied with the
DC590 or download it from www.linear.com/software.
The correct control panel will be loaded automatically.
Figure 2. QuikEval Software
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DEMO MANUAL DC812A
Hardware Setup
Jumper Settings
ANALOG CONNECTIONS
VREF: VREF Select. Select 5V, 4.096V, or 2.5V reference.
To apply an external reference through the VREF turret,
remove this jumper.
DAC VOUT: LTC2606 Output.
VCC: 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 both the VCC jumper
and VREF jumper allows characterization of rail-to-rail
operation of the LTC2606.
ADC: ADC Enable/Disable. Set to ENABLE for operation
with DC590 serial controller. When using in customer’s
end application, the ADC can be completely disabled by
setting jumper to DISABLE.
For very sensitive noise measurements when using LTC
supplied software, set the output voltage and stop reading
the voltage via the collect button on the control panel. This
will stop the ADC from converting.
VREF: The VREF turret is connected directly to the reference
terminals of the LTC2606 and LTC2421 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.
GROUNDING AND POWER CONNECTIONS
Power (VCC): Normally the DC812A is powered by the
DC590 controller. VCC can be supplied to this turret, however the power supply on the DC590 must be disabled!
Refer to the DC590 Quick Start guide for more details on
this mode of operation.
Grounding: Separate power and signal grounds are provided. 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.
Experiments
The following experiments are intended to demonstrate
some of the outstanding features of the LTC2606. All can
be performed using the onboard LTC2421 to monitor
the DAC output voltage. The indicated output voltage will
typically agree with an HP3458A voltmeter to five 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 5V reference has the limitation that
VCC may be slightly lower than VREF, which may affect the
full-scale error. Selecting the 5V reference as the source
for VCC overcomes this, however the total current that the
LTC2606 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.
Resolution
The onboard LTC2421 ADC has an input resolution of
6μV. This will easily resolve a 1 LSB (76μV for VREF = 5V,
62.5μV for VREF = 4.096V) change in the LTC2606 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. Note: It may be necessary to wait for the graph to
clear if a large step has just occurred.
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DEMO MANUAL DC812A
Experiments
Integral Nonlinearity
A rough measurement of INL can be taken using the
onboard ADC. Measure the LTC2606 output 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 64 LSBs, and they will typically
be within 12 LSBs.
Load Regulation /DC Output Impedance
Select “5V REG” for the 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 0.15Ω. Output impedance is typically less
than 0.030Ω (measure DAC voltage at the output pin if
using a voltmeter).
Zero-Scale Error
Set the DAC output to code 0. The measured output should
be less than 9mV and will typically be less than 1mV.
Offset Error
Set the DAC output to code 256. The output voltage should
be within 9mV of the correct value, or VREF × 256/65535.
Gain Error
Set the DAC output to code 65,535. The output voltage should be within 0.7% of VREF, and will typically be
within 0.2%.
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
U7
IC, 24LC025
MICROCHIP, 24LC025
2
3
C3, C7, C10
CAP, X7R, 0.1µF, 16V, 10%, 0402
TDK, C1005X7R1C104KT
3
1
C9
CAP, NPO, 100pF, 50V, 10%, 0402
AVX, 04025A101KAT
4
3
C4-C6
CAP, X5R, 1µF, 6.3V, 20%, 0603
AVX, 06036D105MAT
5
2
C1-C2
CAP, X7R, 1µF, 16V, 20%, 0603
TDK, C1608X7R1C105M
6
1
J1
HEADER, 2×7P, 2mm
MOLEX, 87831-1420
7
0
JP7
DO NOT STUFF
OPTION
8
1
JP1
HEADER, 2×3P, 2mm
COMM CON, 2202S-06-G2
9
5
JP2-JP6
JUMPER, 3-PIN, 2mm
COMM CON, 2802S-03G2
10
1
U5
IC, LT1790ACS6-2.5
LINEAR TECHNOLOGY, LT1790ACS6-2.5
11
1
U4
IC, LT1790ACS6-4.096
LINEAR TECHNOLOGY, LT1790ACS6-4.096
12
1
U3
IC, LT1790ACS6-5
LINEAR TECHNOLOGY, LT1790ACS6-5
13
1
U2
IC, LTC2421CMS
LINEAR TECHNOLOGY, LTC2421CMS
14
1
U1
IC, LTC2606CDD
LINEAR TECHNOLOGY, LTC2606CDD
15
1
U6
IC, NC7WB66 DUAL LOGIC SWITCH
FAIRCHILD SEMI., NC7WB66K8X
16
2
R6, R9
RES, 100Ω, 5%, 1/16W, 0402
AAC, CR05-101JM
17
4
R1, R4-R5, R8
RES, 10kΩ, 5%, 1/16W, 0402
AAC, CR05-103JM
18
3
R2-R3, R10
RES, 4.99kΩ, 1%, 1/16W, 0402
AAC, CR05-4991FM
19
1
R7
RES, 7.5kΩ, 5%, 1/16W, 0402
AAC, CR05-752JM
20
6
E1-E6
TURRET
MILL-MAX, 2308-2
21
7
JP1-JP7
SHUNT
COMM CON, CCIJ2MM-138G
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DEMO MANUAL DC812A
Figure 3. LTC2606CDD, 16-Bit Rail-to-Rail VOUT DAC, I2C Interface
Schematic Diagram
dc812af
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.
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DEMO MANUAL DC812A
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
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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
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