MCP4706A3T-E/CH Microchip Technology, MCP4706A3T-E/CH Datasheet - Page 68

• Manufacturer Part Number: MCP4706A3T-E/CH
• Description: Single, 8-bit NV DAC With Ext Vref And I2C Interface 6 SOT-23 T/R
• Manufacturer: Microchip Technology
• Series: -r

Specifications of MCP4706A3T-E/CH

• Number Of Converters: 1
• Conversion Rate: 1
• Resolution: 8 bit
• Interface Type: I2C
• Settling Time: 6 us
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-23-6
• Maximum Power Dissipation: 452 mW
• Minimum Operating Temperature: - 40 C
• Supply Current: 210 uA
• Number Of Bits: 8
• Data Interface: EEPROM, I²C, Serial
• Voltage Supply Source: Single Supply
• Power Dissipation (max): 452mW
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Number Of Outputs And Type: *
• Lead Free Status / Rohs Status: Details

MCP4706/4716/4726
8.6
Figure 8-7
voltage output capable of up to 24-bit resolution. This
requires two 12-bit DACs. This design is simply a
voltage divider with a buffered output.
As an example, if a similar application to the one
developed in
Using MCP4726”
of 1 mV, and a range of 0V to 4.1V, then 12-bit
resolution would not be adequate.
Step 1: Calculate the resolution needed:
Step 2: Since DAC
Step 3: If R
Step 4: The resulting transfer function is shown in the
FIGURE 8-7:
DAC using MCP4726.
EQUATION 8-6:
DS22272A-page 68
Where:
I
I
V
V
V
2
2
C™
C™
OUT
OA
OB
G = Selected Op Amp Gain
Optional
Optional
4.1V/1 µV = 4.1 x 10
22-bit
DNL = ±0.75 LSb, this design can be attempted
with the 12-bit DAC.
its output only needs to be “pulled” 1/1000 to meet
the 1 µV target. Dividing V
allow the application to compensate for DAC
DNL error.
equation of
MCP4726 (A)
MCP4726 (B)
V
2-wire
V
2-wire
= (V
= (V
REF
REF
=
Designing a Double-Precision
DAC
shows an example design of a single-supply
REF
REF
V
2
OA
is 100Ω, then R
V
V
Section 8.5.1 “Bipolar DAC Example
DD
resolution
DD
* G * DAC A Register Value)/4096
* G * DAC B Register Value)/4096
* R
Example
R
required a resolution of 1 µV instead
2
1
B
R
R
‘s V
+ V
+ R
1
2
V
V
Simple Double Precision
V
OA
OB
OUTB
OB
2
OUT
6
8-6.
.
* R
0.1 µF
1
CALCULATION
is
has a resolution of 1 mV,
Since
needs to be 100 kΩ.
1
OUTA
desired.
V
V
by 1000 would
2
CC
22
CC
–
= 4.2 x 10
+
V
Since
OUT
B
6
‘s
,
8.7
Example 8-8
programmable current source using a voltage follower.
The current sensor resistor is used to convert the DAC
voltage output into a digitally-selectable current source.
The smaller R
across it. However, this also reduces the resolution that
the current can be controlled.
FIGURE 8-8:
Source.
I
2
where
C™
I
I
L
b
Optional
V
=
=
2-wire
MCP47X6
REF
-------------- -
R
I
----
V
β
Building Programmable Current
Source
L
β =
sense
OUT
Common-Emitter Current Gain.
V
×
DD
shows
SENSE
------------ -
β
+
β
1
V
Digitally-Controlled Current
is, the less power dissipated
OUT
© 2011 Microchip Technology Inc.
an
V
example
V
CC
CC
–
+
R
I
SENSE
b
of
(or V
V
Load
DD
building
REF
I
)
L