National Semiconductor DAC121C085, DAC101C081, DAC101C085, DAC121C081, DAC081C081 User Manual

Dec. 19, 2007

National Semiconductor

Rev - 1.0

CMC

Evaluation Board User's Guide

DAC121C08XEB, DAC101C08XEB, DAC081C08XEB

Micro Power Digital-to-Analog Converter (DAC)

with an I2C-Compatible Interface

12-bit 10-bit 8-bit

DAC121C085/

DAC121C081

DAC101C085/

DAC101C081

DAC081C085/

DAC081C081

1 http://www.national.com

Table of Contents

1.0 Introduction ........................................................................................................... 3

2.0 Board Assembly.................................................................................................... 4

3.0 Quick Start............................................................................................................ 4

3.1 Stand-Alone Mode..................................................................................... 4

3.2 Computer Mode......................................................................................... 5

4.0 Functional Description........................................................................................... 6

4.1 Jumper Settings ........................................................................................ 6

2

4.2 I

C Interface .............................................................................................. 6

4.3 DAC Reference Circuitry ........................................................................... 6

4.4 Analog Output ........................................................................................... 7

4.5 Power Supply Connections........................................................................ 7

5.0 Software Operation and Settings .......................................................................... 8

6.0 Evaluation Board Specifications............................................................................ 9

7.0 Hardware Schematic............................................................................................. 10

8.0 Evaluation Board Bill of Materials.......................................................................... 11

A1.0 Summary Tables of Test Points, Jumpers, and Connectors ............................... 12

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1.0 Introduction

A

A

The DAC121C08XEB Design Kit (consisting of the
DAC Evaluation Board and this User's Guide) is
designed to ease evaluation and
design-in of National Semiconductor’s
DAC121C081/DAC121C085 family of Digital-to­Analog Converters (DACs). The Micro-Power
DACs feature Rail-to-Rail Output and an I
Compatible interface. This User’s Guide supports
all three resolutions of the DAC family. The
evaluation board comes with the full-featured
MSOP-8 version of the DAC. For the 12-bit
resolution, the DAC121C085 is used. For the 10­bit resolution, the DAC101C085 is used. For the
8-bit resolution, the DAC081C085 is used. All the
devices in the family (DAC121C085,
DAC101C085, and DAC081C085) will be referred
to as the DAC121C085 in this document.

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 DAC121C085 performance.

2

C-

In the Computer mode, data capture and
evaluation is simplified by connecting this board to
National Semiconductor’s Data Capture Board
(order number W AVEVSN BRD 4.4). 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

.

Note: WaveVision Software version 4.4 or later is
required to evaluate this part with the WV4
Evaluation System.

The WaveVision software allows the user to drive
the DAC121C085 with a variety of preset
waveforms and custom waveforms. The software
also allows the user to configure the I

2

C serial

Interface.

Data transmitted to the DAC121C085, via the

2

C interface, is converted to an analog waveform

I
by U1, the DAC121C085.

JP10

3P3V Select

J1

WV4S

Connector

J3

WV4 Connector

JP5

dd Select

U1

DAC121C085

JP4

Output Load

J4

V

OUT

JP7

V

Select

REF

J2

V

Input

A

JP9

V

Select

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Figure 1: Component and Test Point Locations

2.0 Board Assembly

A

The DAC121C08XEB 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 12 for the Evaluation Board schematic.

3.0 Quick Start

The evaluation board may be used in the Stand­Alone mode or Computer mode. In Stand-Alone
mode, a Pattern Generator is used to interface to
the DAC’s I
WaveVision4 Board is used to drive the DAC’s I
interface. In either case, a Signal Analyzer is used
to evaluate the analog output signal.

3.1 Stand-Alone Mode

Refer to Figure 1 for locations of test points and
major components.

1. Connect a clean analog (not switching) +5V
power source to Power Connector J2 on the
DAC121C08XEB board. Ground the middle
terminal and connect +5V to the bottom
terminal closest to JP9.

2. Make the following required jumper
connections, see Table 1 for more details:

3. Turn on the power source.

4. Configure a pattern generator or other I
master device to interface to the
DAC121C085. Refer to the timing diagrams
in the datasheet for further timing details. The
DAC supports any of the three standard I
speed ranges. Ensure the I
is configured to drive 5V CMOS logic.

5. Connect the I
Interface Header J3 (WV4). Refer to Figure 2
below for connection details. NOTE: The
board comes with pull-up resistors (R6 and
R7). Any other pull-ups on the I
be disabled.

2

C Interface. In Computer Mode, a

• JP9 - pins 2 & 3

• JP7 - pins 2 & 3

• JP6 - pins 1 & 2

• JP8 - pins 1 & 2

2

C master device to Serial

2

C master device

2

C bus must

2

C

2

C

2

C

14

13

12

11

10

9

8

7

5

6

SCL

SD

Figure 2: J3 (WV4) Interface Header

4 2 3

J3
WV4

1

6. The Analog Output signal can be seen DC
coupled at J5, or AC coupled at SMA
connector J4. See the board schematic of
Figure 12 for details.

7. Select the desired output load by adding
jumpers to JP4. Connect a jumper across the
two left pins near the “C” to add a 200pF load
capacitance to ground. Connect a jumper
across the two right side pins near the “R” to
add a 2kΩ resistive load. See Table 1 for
jumper configurations.

2

8. The DAC121C085 will respond to I
0x0C by default with pins A0 and A1 floating.
Change the I

2

C slave address of the DAC by

C address

adding jumpers to JP5. A0 is controlled by
pins 1,2, & 3 of JP5. A1 is controlled by pins
5, 6, & 7. Refer to Table 1 for a detailed
description of the I

2

C Slave address settings.
NOTE: Jumper Setting changes to the pin­configurable slave address will not take effect
until the DAC is power-cycled.

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3.2 Computer Mode

(

)

N

(

)

N

(

)

Refer to Figure 1 for locations of test points and
major components. The board comes configured
for “plug-and-play” WaveVision evaluation.

1. Run the W aveVision 4 program, version 4.4 or
higher is required to interface to the WV4
board. While the program is loading, continue
below.

2. Connect a USB cable between the WV4 board
and the PC running the WaveVision 4
software.

3. Make the following required jumper
connections, see Table 1 for more details:

• JP9 - pins 1 & 2

• JP7 - pins 2 & 3

• JP6 - pins 1 & 2

• JP8 - pins 1 & 2

• JP10 - pins 1 & 2

4. Connect the J1 header on the
DAC121C08XEB evaluation board to the WV4
serial connector (J7) on the WV4 board.
Refer to Figure 3 for the serial connection and

Figure 4 for the J1 header pin out.
Note: J1 on the DAC121C08XEB is

intentionally stuffed on the bottom side of the
board.

+3.3V

SDA

EEPROM

13

11

14

12

+5V

SCL

(EEPROM)

/C

9

10

/C

7

8

GND

SCL

DAC

5

6

GND

3

4

SDA

DAC

1

2

J1
WV4S

Figure 4: J1 (WV4S) Header

5. Perform step 7 of section 3.1 to configure the
loading of the analog output (V

6. Perform step 8 of section 3.1 to configure the

2

C slave address of the DAC.

I

OUT

).

7. Connect a clean (not switching) +5.0V power
source with a 350mA current limit to power
connector J1 on the WV4 board. Turn on the
power supply.

8. Refer to Section 5.0 on Software Operation
and Settings to setup the WaveVision 4
software.

Figure 3: WV4 to DAC121C08XEB Connection

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