March 8, 2006
Rev -2.0
CMC
National Semiconductor
Evaluation Board User's Guide
DAC121S101 12-Bit, DAC101S101 10-Bit, and DAC081S101 8-Bit
Micro Power Digital-to-Analog Converter
with Rail-to-Rail Output
© 2006 National Semiconductor Corporation.
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Table of Contents
1.0 Introduction ................................................................................................. 4
2.0 Board Assembly .......................................................................................... 5
3.0 Quick Start .................................................................................................. 5
3.1 Stand-Alone Mode............................................................................ 5
4.0 Functional Description................................................................................. 5
4.1 Serial Interface ................................................................................. 6
4.2 DAC Reference Circuitry .................................................................. 6
4.3 Analog Output .................................................................................. 6
4.4 Power Supply Connections .............................................................. 6
5.0 Software Operation and Settings ................................................................ 6
6.0 Evaluation Board Specifications.................................................................. 7
7.0 Hardware Schematic ................................................................................... 8
8.0 Evaluation Board Bill of Materials................................................................ 9
A1.0 Summary Tables of Test Points, Jumpers, and Connectors..................... 10
A2.0 Enlarged Timing Diagram ......................................................................... 10
3
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(part number WV4DACIFCABLE at www.national.com).
The Data Capture (WV4) Board is connected to a
personal computer running WaveVision software
through a USB port. The WaveVision4 software runs on
Microsoft Windows, and the latest version can be
downloaded
from
the
web
at
http://www.national.com/adc.
1.0 Introduction
The DAC121S101EVAL Design Kit (consisting of the
DAC121S101 Evaluation Board and this User's Guide)
are designed to ease evaluation and design-in of the
National
Semiconductor
DAC121S101
12-bit,
DAC101S101 10-bit, and DAC081S101 8-bit MicroPower Digital-to-Analog Converters with Rail-to-Rail
Output. This family of pin-compatible DACs, will be
referenced throughout this document as the
DAC121S101.
Note: WaveVision Software version 4.2 or later is
required to evaluate this part with the WV4 Evaluation
System.
The evaluation board can be used in either of two
modes. In the Stand-Alone mode, suitable test
equipment, such as a pattern generator and signal
analyzer, can be used with the board to evaluate the
DAC121S101 performance.
The WaveVision software allows the user to drive the
DAC121S101 with a variety of preset waveforms and
custom waveforms. The software also allows the user
to select the clock frequency of the serial interface.
Data transmitted to the DAC121S101 via a serial
interface is converted to an analog waveform by U1/U2,
the DAC121S101.
In the Computer mode, data capture and evaluation is
simplified by connecting this board to National
Semiconductor’s Data Capture Board (order number
WAVEVSN BRD 4.0) with a custom interface cable
J1
VOUT_AC
TP2
VOUT_DC
JP3
Output Load
U1/U2
DAC121S101
J3
Serial Interface
J2
WV4S
Connector
J4
VA_REMOTE
JP1
VA Selection
VA1
Local VA Adjust
Figure 1: Component and Test Point Locations
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5.
2.0 Board Assembly
The DAC121S101 evaluation board comes fully
assembled and ready for use. Refer to the Bill of
Materials for a description of components, to Figure 1
for major component placement, and to Figure 4 for the
Evaluation Board schematic.
3.2 Computer Mode
3.0 Quick Start
Refer to Figure 1 for locations of test points and major
components.
The DAC121S101 evaluation board may be used in the
Stand-Alone mode or Computer mode. In Stand-Alone
mode, a Pattern Generator is used to drive the
DAC121S101, and a Signal Analyzer is used to
evaluate the analog output signal. In Computer Mode,
a WaveVision4 Board is used to drive the
DAC121S101 and a Signal Alalyzer is used to evaluate
the analog output signal.
1.
2.
3.
Refer to Figure 1 for locations of test points and major
components.
2.
Run the WaveVision4 program. While the program
is loading, continue below.
Connect the “WV4DACIFCABLE” cable between
J3 of the DAC121S101 evaluation board and J3 of
the WV4 board. Note: the “WV4DACIFCABLE” is
available at www.national.com.
3.1 Stand-Alone Mode
1.
Select the desired output load by adding jumpers
to JP3. Connecting a jumper across pins 1 and 2
connects a 200pF load capacitance to ground.
Connecting a jumper across pins 3 and 4 selects a
2kΩ resistive load. See Table 1 for jumper
configurations.
4.
Connect a clean analog (not switching) +5V power
source to Power Connector J4 on the
DAC121S101 board and turn on the power. Place
a jumper across pins 2 and 3 of JP1 to select
VA_REMOTE.
Create the digital waveforms seen in Figure 2 with
your Logic Generator. Ensure that SCLK doesn’t
exceed 30MHz. Refer to “Section 4.1: Serial
Interface” and the DAC121S101 Datasheet for
further details.
5.
5.
6.
7.
8.
Connect a USB cable between the WaveVision4
Board and the PC running the WaveVision4
software.
Connect a clean analog (not switching) +5V power
source to Power Connector J1 on the WaveVision4
Board.
Place a jumper across pins 2 and 3 of JP1 on the
DAC121S101 board to select VA_REMOTE.
Using a jumper cable, connect TP9 of the
WaveVision4 board to TP6 of the DAC121S101
board.
Using another jumper cable, connect TP10 of the
WaveVision4 board to TP4 of the DAC121S101
board. See Section 4.4 for detailed Power Supply
Information.
Perform steps 4 and 5 of section 3.1 above.
Refer to section 5.0 on Software Operation and
Settings.
4.0 Functional Description
Table 1 describes the function of the various jumpers
on the ADC121S625 evaluation board. The Evaluation
Board schematic is shown in Figure 4.
Figure 2: Digital Input Timing Diagram
(Refer to Appendix 2.0 for an enlarged version)
3.
4
SYNC
5
6
SCLK
7
8
DIN
9
10
J3
2
3
JP1
Select VA_LOCAL
from VR1 adjust
Select VA_REMOTE
from J4
JP2
NC
Not used
Pins 1 & 2
Pins 3 & 4
Select 200pF
Output Load
Capacitance
Select 2kΩ Output
Load Resistance
Jumper
JP3
Figure 3: J3 Serial Interface Header
4.
Pins 2 & 3
Jumper
Connect your Logic Generator to Serial Interface
header J3. Refer to Figure 3 below for connection
details.
1
Pins 1 & 2
The Analog Output signal can be seen DC coupled
at TP2, or AC coupled at BNC connector J1. See
the board schematic of Figure 4 for details.
Table 1: Jumper Configurations
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must be powered by an external supply. In either case,
remember that the supply voltage and reference
voltages are tied together on the DAC121S101.
4.1 Serial Interface
In Computer Mode, the serial interface is driven by the
WaveVision4 board. The WaveVision4 software allows
the user to drive the DAC121S101 with various
digitized signals. Refer to “Software Operation and
Settings” for further information.
If you wish to supply VA externally, connect a DC
voltage supply to connector J4 and place a jumper
across pins 2 and 3 of JP1 to select VA_REMOTE.
This voltage (VA) can be set anywhere from +2.7V to
+5.5V. Note: For computer mode, +3.3V must be
supplied to the DAC121S101 board at TP4.
In Stand-Alone Mode, The serial interface must be
driven by an external device. The three-wire interface
(SCLK, SYNC, DIN) is compatible with SPI, QSPI and
MICROWIRE, as well as most DSPs. See the Timing
Diagram (Figure 2) for information on a write sequence.
Since the supply voltage (VA) serves as the reference
for the DAC121S101, ensure a clean power supply is
used.
The maximum digital input level of the three-wire
interface is independent of the analog supply voltage
(VA). The range of all digital inputs is 0V to 5.25V
regardless of VA.
If you wish to use the local supply from the
WaveVision4 Board, place a jumper across pins 2 and
3 of JP1. Using a jumper cable, connect TP9 of the
WaveVision4 board to TP6 of the DAC121S101 board.
This connection will supply +5V to VA on the
DAC121S101 board.
Using another jumper cable,
connect TP10 of the WaveVision4 board to TP4 of the
DAC121S101 board.
A write sequence begins by bringing the SYNC line low.
Once SYNC is low, the Binary data on the DIN line is
clocked into the 16-bit serial input register on the falling
edges of SCLK. On the 16th falling clock edge, the last
data bit is clocked in and the programmed function (a
change in the mode of operation and/or a change in the
DAC register contents) is executed. At this point the
SYNC line may be kept low or brought high. In either
case, it must be brought high for the minimum specified
time before the next write sequence as a falling edge of
SYNC will initiate the next write cycle.
5.0 Software Operation and Settings
The WaveVision software is included with the
WaveVision4 board and the latest version can be
downloaded
from
National's
web
site
at
http://www.national.com/adc.
WaveVision software
version 4.2 or later is required to evaluate this device
with the WV4 system.
Since the SYNC and DIN buffers draw more current
when they are high, they should be idled low between
write sequences to minimize power consumption.
To install this software, follow the procedure in the
WAVEVSN BRD 4.0 User's Guide. Once the software
is installed, run it and set it up as follows:
Please refer to the DAC121S101 datasheet for more
information.
Note: Before continuing, ensure that the WaveVision
Hardware is setup according to Section 3.2.
4.2 DAC Reference Circuitry
The supply voltage for the DAC121S101 serves as its
voltage reference, and does not need to be supplied
separately. The analog output range of the
DAC121S101 can be scaled by adjusting the supply
voltage (VA). This voltage can be set anywhere from
+2.7V to +5.5V.
1.
From the WaveVision main menu, go to Settings,
then Capture Settings to open the System Settings
dialog.
2.
Under board type, select WaveVision4 (USB).
3.
Turn on the power to both boards, then click on the
"Test" button and await the firmware download.
After the firmware has downloaded, WaveVision
will open up a control panel for the DAC121S101.
4.
Click on the "Accept" button to close the System
Settings Dialog.
5.
From the DAC121S101 Control Panel, configure
the digital waveform to be converted by the DAC.
Please see the WaveVision4 User’s Manual for
detailed instructions. The ability to drive preset
waveforms or custom data is provided.
6.
Press the “Start” button to begin driving the digital
waveform to the DAC.
4.3 Analog Output
The analog output of this Eval board is available at the
BNC connector, J1. The output at J1 is AC coupled.
The board also provides a DC coupled output at TP2.
If you are using a spectrum analyzer to look at the
output of the DAC121S101, the AC coupled output (J1)
is recommended.
For very low frequency (i.e. less than 1kHz), use TP2 to
see the output signal DC coupled. For an AC coupled
output at low frequencies, simply replace the AC
coupling capacitor at C3 with a larger capacitor.
4.4 Power Supply Connections
The WaveVision4 Board will continuously send the
waveform out to the DAC121S101 until the “Stop”
button is pressed. Please refer to Section 4.3 for
details on measuring the Analog Output of the DAC.
In Computer mode, the board can be powered by either
an external supply or the local WaveVision4 board
supply. In Stand-alone mode, the DAC121S101 board
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The Digital Waveform is plotted in the main
WaveVision window for added convienience. This
waveform may be further analyzed by clicking on the
magnifying glass icon, then clicking and dragging
across a specific area of the plot for better data
inspection. See the WaveVision4 Board User's Guide
for details.
If this board is used in conjunction with the WAVEVSN
BRD 4.0 Data Capture Board and WaveVision
software, a USB cable is needed to connect
WAVEVSN BRD 4.0 to the host computer. See the
WaveVision4 Board User's Guide for details.
6.0 Evaluation Board Specifications
Board Size:
Power Requirements
Max Clock Frequency:
Analog Output
AC Coupled
Output Range:
Impedance:
2.44" x 2.19" (6.2 cm x 5.6 cm)
Min: +2.7V , 3mA Max: +5.5V, 5 mA
30 MHz
-(VA/2) to (VA/2)
User Selectable: 2KΩ, 200pF, or ∞.
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1
2
VA_REMOTE
AGND
J4
VA_REMOTE
D2
1N4001
VA
VA
R3
NS
VA
VA_REMOTE
NS
D3
10uF
C11
5P5V
RED LED
D1
3P3V
3P3V
CAP
200pF
C4
JP3
LOAD_SEL
C3
0.1uF
1
10K
VR1
0.1uF
C14
R5
-
+
C15
4
3
VA_LOCAL ADJUST
1
J1
VOUT_ac
2
3P3V
R2
200
TP4
3P3V
TP6
VA
1
VOUT_ac
1
2
+
NS
0
C6
NS
C2
C10
0.1uF
C9
1uF
R4
0
TP5
AGND
1uF 0.1uF
U4
LMV710M5
1
NS
C1
C5
RES
R1
2K
1
+
1
5
3
+
4
TP2
VOUT_DC
SY NCB
SCLK
DIN
GND
VA
VA
GND
VOUT
8
4
5
6
5
6
7
VA SELECTION
JP1
VA SELECTION
VA_REMOTE
DIN
SCLK
SY NCB
U2
DAC121S101CIMK
VOUT
NC
NC
VA
U1
NS
AGND
VA
3
2
1
4
3
2
1
VA_LOCAL
1
+
2
3P3V
10uF
C12
C13
0.1uF
10
9
3P3V
8
6
7
DIN
4
5
2
J3
HEADER 5X2
3
3P3V
SCL
5P5V
R7
0
3P3V
R6
NS
SCL
SDA
USI
5P5V
14
12
10
SCLK
1
13
11
9
8
6
7
4
5
2
3
1
SY NCB
3P3V
3P3V
SDA
DIN
SCLK
SYNCB
J2
HEADER 7X2
6
VA
1
2
3
8
VCC
A0
1
7
WP
A1
2
SCL
A2
5
3P3V
3
SDA
GND
8
4
AGND
U5
24C02
TP3
AGND
1
TP1
AGND
AGND
7.0 Hardware Schematic
Figure 4: DAC121S101 Evaluation Board Schematic
http://www.national.com
8.0 Evaluation Board Bill of Materials
Qty.
Reference
PCB Footprint
Rating
Value
1
C1
sm/c_1206
Source
Source Part #
10V
NS
2
C15,C2
sm/c_0805
10V
NS
5
C3,C6,C10,
C13,C14
sm/c_0805
10V
0.1uF
1
C4
sm/c_0805
10V
200pF
2
C9,C5
sm/c_1206
10V
1uF
2
C11,C12
sm/ct_3216_12
1
D1
sm/led_21
Digikey
516-1440-1-ND
10V
RED LED
10uF
1
D2
DAX2/DO41
Digikey
1N4001GICT-ND
1N4001
1
D3
sm/led_21
Digikey
516-1440-1-ND
NS
1
JP1
blkcon.100/vh/tm1sq/w.100/3
Digikey
A26513-40-ND
VA SELECTION
1
JP3
blkcon.100/vh/tm2oe/w.200/4
Digikey
A26529-40-ND
LOAD_SEL
1
J1
rf/bnc/r1.350_21
Digikey
ARF1177-ND
VOUT_ac
1
J2
blkcon/2mm/ra/tm2oe/w2mm/14
Digikey
S2200-07-ND
HEADER 7X2
1
J3
BLKCON.100/…/shroud
Digikey
A26529-40-ND
HEADER 5X2
1
J4
term_block/.200/2pos
Digikey
ED1609-ND
VA_REMOTE
1
R1
sm/r_0805
2K
1
R2
sm/r_0805
200
2
R6,R3
sm/r_0805
NS
3
R4,R5,R7
sm/r_0805
0
3
TP1,TP3,TP5
blkcon.100/vh/tm1sq/w.100/1
Digikey
5011K-ND
AGND
1
TP2
blkcon.100/vh/tm1sq/w.100/1
Digikey
5011K-ND
VOUT_DC
1
TP4
blkcon.100/vh/tm1sq/w.100/1
Digikey
5011K-ND
3P3V
1
TP6
blkcon.100/vh/tm1sq/w.100/1
Digikey
5011K-ND
VA
1
U1
sog.65m/8/wg4.80/l3.00
1
U2
sm/sot23-6
1
U4
sm/sot23-5
1
U5
sog.050/8/wg.244/l.200
1
VR1
vres4
NS
DAC121S101CIMK
DAC101S101CIMK
DAC081S101CIMK
Digikey
LMV710M5CT-ND
LMV710M5
Digikey
3386F-103-ND
10K
24C02
9
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APPENDIX
A1.0 Summary Tables of Test Points, Jumpers, and Connectors
Test Points on the DAC121S101 Evaluation Board
TP1: AGND
Ground. Located at the top center of the board.
TP2: VOUT_DC
DC Coupled Analog Output test point. Located at the top center of the board.
TP3: AGND
Ground. Located at the top Right of the board.
TP4: 3P3V
3.3V test point. Located at the right edge of the board.
TP5: AGND
Ground. Located in the center of the board.
TP6: VA
VA Test Point. Located in the center of the board.
Connectors on the DAC121S101 Evaluation Board
J1: BNC Connector
VOUT_AC. AC Coupled Analog Output.
J2: WV4S Header
Wave Vision 4 Serial connector (Future Use)
J3: Serial Interface
Header
Serial Interface connector. Logic Input. (Refer to Figure 3 for a pin-out diagram.)
J4: Terminal Block
VA_REMOTE. External power supply connector.
Selection Jumpers on the DAC121S101 Evaluation Board (Refer to Table 1 in Section 4.0 for configuration details)
JP1: VA SEL
Selects source of VA.
JP2: Not Used
Not Used.
JP3: Output Load
Configures the output load.
A2.0 Enlarged Timing Diagram
10
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SEMICONDUCTOR'S END USER LICENSE AGREEMENT. DO NOT USE THIS PRODUCT UNTIL YOU HAVE READ AND
AGREED TO THE TERMS AND CONDITIONS OF THAT AGREEMENT. IF YOU DO NOT AGREE WITH THEM, CONTACT THE
VENDOR WITHIN TEN (10) DAYS OF RECEIPT FOR INSTRUCTIONS ON RETURN OF THE UNUSED PRODUCT FOR A
REFUND OF THE PURCHASE PRICE PAID, IF ANY.
The DAC121S101, DAC101S101, & DAC081S101 Evaluation Boards are intended for product evaluation purposes only and are
not intended for resale to end consumers, are not authorized for such use and are not designed for compliance with European EMC
Directive 89/336/EEC, or for compliance with any other electromagnetic compatibility requirements.
National Semiconductor Corporation does not assume any responsibility for use of any circuitry or software supplied or described.
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