MCP4912-E/SL Microchip Technology, MCP4912-E/SL Datasheet - Page 32

• Manufacturer Part Number: MCP4912-E/SL
• Description: DAC 10BIT DUAL W/SPI 14SOIC
• Manufacturer: Microchip Technology

Specifications of MCP4912-E/SL

• Number Of Converters: 2
• Settling Time: 4.5µs
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Number Of Bits: 10
• Data Interface: Serial, SPI™
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Number Of Dac Outputs: 2
• Resolution: 10 bit
• Interface Type: SPI
• Supply Voltage (max): 6.5 V
• Supply Voltage (min): 2.7 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 55 C
• Supply Current: 350 uA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power Dissipation (max): -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MCP4902/4912/4922
6.7
Example 6-5
voltage output capable of up to 24-bit resolution from a
dual 12-bit DAC. This design is simply a voltage divider
with a buffered output.
As an example, if a application similar to the one
developed in Section 6.5.1 “Design Example: Design
a Bipolar DAC Using Example 6-3 with 12-bit
MCP4922 or MCP4921” 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:
DS22250A-page 32
Designing a Double-Precision
DAC Using a Dual DAC
SPI
V
REF
illustrates how to design a single-supply
V
V
V
3
MCP4922
MCP4922
OUTA
O
OUTB
V
V
DD
DD
=
SIMPLE, DOUBLE-PRECISION DAC WITH MCP4922
V
-----------------------------------------------------
=
=
OUTA
V
V
REFA
REFB
DAC
DAC
R
R
2
1
+
+
G
G
B
A
V
V
R
R
A
B
V
(Course Adjust)
OUTA
OUTB
2
(Fine Adjust)
D
-------
2
D
-------
2
1
OUTB
12
12
>> R
A
B
R
1
2
R
R
2
1
0.1 µF
Step 1: Calculate the resolution needed:
Step 2: Since DAC
Step 3: If R
Step 4:The resulting transfer function is not perfectly
4.1V/1 µV = 4.1x10
bit resolution is desired. Since DNL = ±0.75
LSb, this design can be attempted with the
MCP4922.
its output only needs to be “pulled” 1/1000 to
meet the 1 µV target. Dividing V
would allow the application to compensate for
DAC
linear,
Example
V
V
G = Gain selection (1x or 2x)
D = Digital value of DAC (0- 4096)
CC
CC
2
B
is 100, then R
+
–
’s DNL error.
as
6-5.
B
’s V
shown
 2010 Microchip Technology Inc.
OUTB
6
V
. Since 2
1
O
has a resolution of 1 mV,
needs to be 100 k.
in
the
22
= 4.2x10
OUTA
equation
by 1000
6
, 22-
of