MCP4922-E/P Microchip Technology, MCP4922-E/P Datasheet - Page 22

• Manufacturer Part Number: MCP4922-E/P
• Description: IC DAC 12BIT DUAL W/SPI 14DIP
• Manufacturer: Microchip Technology

Specifications of MCP4922-E/P

• Number Of Converters: 2
• Package / Case: 14-DIP (0.300", 7.62mm)
• Settling Time: 4.5µs
• Number Of Bits: 12
• Data Interface: Serial, SPI™
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Through Hole
• Resolution: 12 bit
• Interface Type: Serial (3-Wire, SPI, Microwire)
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power Dissipation (max): -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MCP4921/4922
6.4.1.2
When calibrating a set point or threshold of a sensor,
rarely does the sensor utilize the entire output range of
the DAC. If the LSB size is adequate to meet the appli-
cation’s accuracy needs, then the resolution is sacri-
ficed without consequences. If greater accuracy is
needed, then the output range will need to be reduced
to increase the resolution around the desired threshold.
EXAMPLE 6-2:
DS21897A-page 22
Thevenin
Equivalent
SPI™
V
Building a “Window” DAC
REF
3
MCP492X
V
V
DD
OUT
Single-Supply “Window” DAC.
R
V
V
23
23
trip
=
=
=
V
=
REF
------------------
R
----------------------------------------------------- -
V
R
V
------------------------------------------- -
V
2
CC+
2
OUT
OUT
+
G
R
R
3
-------
2
R
D
R
3
12
R
R
2
2
23
2
+
R
+
+
R
+
1
R
R
R
23
V
V
3
3
2
23
CC-
V
V
R
CC+
CC-
1
R
3
R
sense
V
OUT
If the threshold is not near V
a “window” around the threshold has several advan-
tages. One simple method to create this “window” is to
use a voltage divider network with a pull-up and pull-
down resistor.
illustrates this concept.
The MCP492X’s low, ±0.75 (max.) DNL performance
is critical to meet calibration accuracy in production.
R
0.1 µF
1
V
trip
V
23
G = Gain select (1x or 2x)
D = Digital value of DAC (0 – 4096)
R
23
V
Example 6-2 and
O
Comparator
 2004 Microchip Technology Inc.
V
V
CC+
CC-
REF
or AV
SS
, then creating
Example 6-4