MCP4921-E/SN Microchip Technology, MCP4921-E/SN Datasheet - Page 28

• Manufacturer Part Number: MCP4921-E/SN
• Description: IC DAC 12BIT SNGL W/SPI 8SOIC
• Manufacturer: Microchip Technology

Specifications of MCP4921-E/SN

• Number Of Converters: 1
• Package / Case: 8-SOIC (3.9mm Width)
• 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: Surface Mount
• 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: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Package: 8SOIC N
• Architecture: Resistor-String
• Digital Interface Type: Serial (3-Wire, SPI, Microwire)
• Number Of Outputs Per Chip: 1
• Output Type: Voltage
• Full Scale Error: 1 %FSR
• Integral Nonlinearity Error: ±12 LSB
• Maximum Settling Time: 4.5(Typ) us
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power Dissipation (max): -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MCP4901/4911/4921
6.4
The MCP4901/4911/4921 devices are rail-to-rail volt-
age output DAC devices designed to operate with a
V
enough to drive small signal loads directly. Therefore, it
does not require an external output buffer for most
applications.
6.4.1
A
digitally-controlled set points and/or calibration of
variable parameters, such as sensor offset or slope.
For example, the MCP4921 and MCP4922 provide
4096 output steps. If the external voltage reference
(V
output step size is desired, a lower external voltage
reference is needed.
EXAMPLE 6-1:
DS22248A-page 28
DD
REF
(b) Dual Output DAC:
(a) Single Output DAC:
common
range of 2.7V to 5.5V. Its output amplifier is robust
) is 4.096V, the LSb size is 1 mV. If a smaller
Single-Supply Operation
DC SET POINT OR CALIBRATION
V
SPI
application
REF
V OUT
V trip
3-wire
EXAMPLE CIRCUIT OF SET POINT OR THRESHOLD CALIBRATION.
MCP4912
MCP4922
MCP4902
MCP4901
MCP4911
MCP4921
=
=
V
V
V OUT
DD
DAC
REF
for




G
--------------------
R 1
DAC

D
------
2
R 2
+
V
N
n
OUT
R 2



devices
R
1
is
R
D
G = Gain selection (1x or 2x)
2
N = DAC Bit Resolution
n
= Digital value of DAC (0-4095) for MCP4921/MCP4922
= Digital value of DAC (0-255) for MCP4901/MCP4902
= Digital value of DAC (0-1023) for MCP4911/MCP4912
R
SENSE
6.4.1.1
If the application is calibrating the bias voltage of a
diode or transistor, a bias voltage range of 0.8V may be
desired with about 200 µV resolution per step. Two
common methods to achieve a 0.8V range is to either
reduce V
DAC’s output.
Using a V
the
occasionally, when using a low-voltage V
floor causes an SNR error that is intolerable. Using a
voltage divider method is another option and provides
some advantages when V
when the desired output voltage is not available. In this
case, a larger value V
scale the output range down to the precise desired
level.
Example 6-1
bypass capacitor on the output of the voltage divider
plays a critical function in attenuating the output noise
of the DAC and the induced noise from the
environment.
V
DD
desired
REF
REF
0.1 uF
Decreasing Output Step Size
to 0.82V or use a voltage divider on the
illustrates this concept. Note that the
is an option if the V
output
V
TRIP
REF
 2010 Microchip Technology Inc.
voltage
Comparator
REF
is used while two resistors
needs to be very low or
V
V
CC
CC
REF
+
–
range.
is available with
REF
, the noise
However,
V
O