MCP4821-E/MS Microchip Technology, MCP4821-E/MS Datasheet - Page 30

• Manufacturer Part Number: MCP4821-E/MS
• Description: IC DAC 12BIT W/SPI 8MSOP
• Manufacturer: Microchip Technology

Specifications of MCP4821-E/MS

• Data Interface: Serial, SPI™
• Settling Time: 4.5µs
• Number Of Bits: 12
• Number Of Converters: 1
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Resolution (bits): 12bit
• Input Channel Type: Serial
• Supply Voltage Range - Analog: 2.7V To 5.5V
• Supply Current: 350µA
• Digital Ic Case Style: MSOP
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power Dissipation (max): -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

MCP4801/4811/4821
6.8
Example 6-5
voltage output capable of up to 24-bit resolution by
using 12-bit DACs. This design is simply a voltage
divider with a buffered output.
As an example, if an application similar to the one
developed
Design a Bipolar DAC Using Example 6-3 with 12-
bit MCP4821 or MCP4822” required a resolution of
1 µV instead of 1 mV, and a range of 0V to 4.1V, then
12-bit resolution would not be adequate.
EXAMPLE 6-5:
DS22244B-page 30
SPI
Designing a Double-Precision
DAC
V
V
OUTA
OUTB
in
illustrates how to design a single-supply
V
3-wire
O
V
V
Section 6.6.1
DAC
DAC
=
=
DD
DD
=
2.048 G
2.048 G
V
----------------------------------------------------- -
B
OUTA
SIMPLE, DOUBLE-PRECISION DAC WITH MCP4821
A


R
R
V
2
1
V
A
B
OUTA
+
+
OUTB


-------
2
D
D
-------
2
V
R
12
“Design
12
A
B
OUTB
2
for Fine Adjustment
for Fine Adjustment
R
1
Example:
R
1
>> R
2
R
R
2
Step 1: Calculate the resolution needed:
Step 2: Since DAC
Step 3: If R
Step 4: The resulting transfer function is shown in the
1
G
D
4.1V/1 µV = 4.1 x 10
22-bit
DNL = ±0.75 LSb, this design can be done with
the 12-bit MCP4821 or MCP4822 DAC devices.
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
n
x
0.1 µF
= Gain selection (1x or 2x)
= Digital value of DAC (0-4096)
2
is 100, then R
resolution
Example
V
V
B
CC
’s V
CC
+
–
 2010 Microchip Technology Inc.
OUTB
6
6-5.
.
1
is
has a resolution of 1 mV,
Since
needs to be 100 k.
OUTA
desired.
by 1000 would
2
22
V
= 4.2 x 10
O
Since
B
6
’s
,