DAC121C08XEB/NOPB National Semiconductor, DAC121C08XEB/NOPB Datasheet - Page 6

• Manufacturer Part Number: DAC121C08XEB/NOPB
• Description: BOARD EVAL FOR DAC121C081/5
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of DAC121C08XEB/NOPB

• Number Of Dac's: 1
• Number Of Bits: 12
• Outputs And Type: 1, Single Ended
• Data Interface: Serial
• Settling Time: 6µs
• Dac Type: Voltage
• Voltage Supply Source: Single
• Operating Temperature: -40°C ~ 125°C
• Utilized Ic / Part: DAC121C081/5
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: DAC121C08XEB

4.0 Functional Description
4.1 Jumper Settings
Table 1 describes the function of the various
jumpers
board. The evaluation board schematic is shown
in Figure 12.
Right side
pins near
pins near
Left side
Address
Jumper
JP10
0x0C
0x0D
0x0E
0x0A
0x4C
0x4D
0x4E
0x08
0x09
JP4
JP5
JP6
JP7
JP8
JP9
“C”
“R”
Table 1: Jumper Configurations
on the DAC121C08XEB evaluation
Use 3.3V supply
Use V
Connect a 2kΩ load resistance from
Connect a 200pF load capacitance
from the WV4
Jumper JP5 (I
V
Use external
Jumper JP4 (V
I
Enable V
WV4 board
Short pins 2 & 3 and pins 6 & 7.
Short pins 1 & 2 and pins 6 & 7.
Short pins 2 & 3 and pins 5 & 6.
Short pins 1 & 2 and pins 5 & 6.
Pins 1 & 2
2
REF
V
Enable V
C Address Select (See Below)
OUT
board
A
from J2.
from the
Load Select (See Below)
from V
Short pins 2 & 3.
Short pins 1 & 2.
Short pins 6 & 7.
Short pins 5 & 6.
REF
V
No jumpers
A
OUT
supply to the DAC.
supply to the DAC.
OUT
2
C Address Select)
to GND
OUT
to GND
3.3V supply from
Use external V
Set V
Load Select)
Use external
Pins 2 & 3
from J2.
TP6.
REF
= V
A
A
6
4.2 I
The DAC supports all three I
Hs-Mode (3.4MHz).
DAC conversion rate is 188.9kHz. The board is
designed with 1kΩ I
the SDA and SCL lines (R6 & R7). Also, series
resistors for SCL and SDA are designed into the
board (R8 & R9). The board is shipped with 51Ω
series resistors which can be increased to
interface to a noisy I
In Computer Mode, the I
the WaveVision4 board.
software allows the user to drive the DAC121C085
with various digitized signals. Refer to Section 5.0
“Software Operation and Settings” for further
information.
In Stand-Alone Mode, the I
driven by an external device. See section 1.4.5 of
the DAC121C081/DAC121C085 datasheet for a
typical write sequence timing diagram.
The maximum digital input level of the I
interface depends on the analog supply voltage
(V
logic levels.
section of the datasheet for further details.
The SDA signal is accessible by connecting to
pin 2 of the WV4 connector (J3). The SCL signal
is accessible by connecting to pin 6 of J3.
Please refer to section 1.4 of the datasheet for a
detailed description of the I
the Philips I2C Specification for further details.
4.3 DAC Reference Circuitry
The reference voltage for the DAC121C085 is
selected by JP7. (See Table 1 for details.) The
reference can either be selected as the V
or an externally supplied voltage (J2). The analog
output range of the DAC121C085 can be scaled
by adjusting the reference voltage (V
lower the V
can be set anywhere from 1.0V to V
independent of V
from +2.7V to +5.5V. In any case, V
to no PSRR and must be as clean as possible to
reduce noise feedthrough on V
A
).
2
C Interface
The interface operates at normal CMOS
REF
, the smaller the output range. V
See the Electrical Characteristics
REF
http://www.national.com
2
C bus.
2
C pull-up resistors on both
In Hs-Mode the maximum
and can be set anywhere
2
C interface is driven by
2
2
C interface. Refer to
C interface must be
2
C speeds, including
OUT
The WaveVision4
.
REF
REF
A
has little
A
).
. V
supply
A
The
REF
2
C
is