DAC8512FSZ-REEL7 Analog Devices Inc, DAC8512FSZ-REEL7 Datasheet - Page 10

• Manufacturer Part Number: DAC8512FSZ-REEL7
• Description: IC,D/A CONVERTER,SINGLE,12-BIT,BICMOS,SOP,8PIN
• Manufacturer: Analog Devices Inc

Specifications of DAC8512FSZ-REEL7

• Settling Time: 16µs
• Number Of Bits: 12
• Data Interface: Serial
• Number Of Converters: 1
• Voltage Supply Source: Single Supply
• Power Dissipation (max): 2.5mW
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Number Of Channels: 1
• Resolution: 12b
• Conversion Rate: 62.5KSPS
• Interface Type: Serial (3-Wire)
• Single Supply Voltage (typ): 5V
• Dual Supply Voltage (typ): Not RequiredV
• Architecture: R-2R
• Power Supply Requirement: Single
• Output Type: Voltage
• Integral Nonlinearity Error: 2+/- LSB
• Single Supply Voltage (min): 4.75V
• Single Supply Voltage (max): 5.25V
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DAC8512
Operating the DAC8512 on +12 V or +15 V Supplies Only
Although the DAC8512 has been specified to operate on a
single, +5 V supply, a single +5 V supply may not be available in
many applications. Since the DAC8512 consumes no more than
2.5 mA, maximum, then an integrated voltage reference, such as
the REF02, can be used as the DAC8512 +5 V supply. The
configuration of the circuit is shown in Figure 26. Notice that
the reference’s output voltage requires no trimming because of
the REF02’s excellent load regulation and tight initial output
voltage tolerance. Although the maximum supply current of the
DAC8512 is 2.5 mA, local bypassing of the REF02’s output
with at least 0.1 F at the DAC’s voltage supply pin is recom-
mended to prevent the DAC’s internal digital circuits from af-
fecting the DAC’s internal voltage reference.
Measuring Offset Error
One of the most commonly specified endpoint errors associated
with real world nonideal DACs is offset error.
In most DAC testing, the offset error is measured by applying
the zero-scale code and measuring the output deviation from 0
volt. There are some DACs where offset errors may be present
but not observable at the zero scale because of other circuit limi-
tations (for example, zero coinciding with single-supply ground).
In these DACs, nonzero output at zero code cannot be read as
the offset error. In the DAC8512, for example, the zero-scale
error is specified to be 3 LSBs. Since zero scale coincides with
zero volt, it is not possible to measure negative offset error.
Figure 26. Operating the DAC8512 on +12 V or +15 V
Supplies Using a REF02 Voltage Reference
Figure 27. Measuring Zero-Scale or Offset Error
SCLK
SET CODE = 000
CLR
+12V OR +15V
SDI
CS
LD
REF02
4
2
2
6
5
3
4
0.1 F
0.1 F
SCLK
CLR
6
H
SDI
CS
LD
DAC8512
AND MEASURE V
GND
V
+5V
DD
1
7
2
6
5
3
4
DAC8512
OUT
8
GND
V
1
DD
7
R
V–
0.1 F
200 A, MAX
8
V
OUT
V
OUT
–10–
By adding a pull-down resistor from the output of the DAC8412
to a negative supply as shown in Figure 27, offset errors can
now be read at zero code. This configuration forces the output
p-channel MOSFET to source current to the negative supply
thereby allowing the designer to determine in which direction the
offset error appears. The value of the resistor should be such that,
at zero code, current through the resistor is 200 A, maximum.
Bipolar Output Operation
Although the DAC8512 has been designed for single-supply op-
eration, bipolar operation is achievable using the circuit illus-
trated in Figure 28. The circuit uses a single-supply, rail-to-rail
OP295 op amp and the REF03 to generate the –2.5 V reference
required to level-shift the DAC output voltage. Note that the –
2.5 V reference was generated without the use of precision resis-
tors. The circuit has been configured to provide an output
voltage in the range –5 V V
plementary offset binary. Although each DAC LSB corresponds
to 1 mV, each output LSB has been scaled to 2.44 mV. Table
III provides the relationship between the digital codes and out-
put voltage.
The transfer function of the circuit is given by:
and, for the circuit values shown, becomes:
SCLK
CLR
SDI
LD
CS
V
V
O
O
= –1 mV
= –2.44 mV
6
5
2
3
4
0.1 F
Figure 28. Bipolar Output Operation
REF03
DAC8512
10 F
+5V
+
2
4
GND
+5V
V
Digital Code
1
DD
7
6
5
Digital Code + 5 V
0.1 F
TRIM
2.5V
8
10k
12.7k
–2.5V
R1
P1
10k
OUT
100
R2
R4
R1
+5 V and is coded in com-
10k
P2
A1, A2 = 1/2 OP295
2
3
R3
247k
+ 2.5
A1
0.01 F
ZERO SCALE
23.7k
ADJUST
6
5
R4
R2
R4
1
A2
–5V
+5V
FULL SCALE
8
4
ADJUST
500
7
–2.5V
P3
REV. A
–5V
V
O
+5V