MCP4801T-E/P MICROCHIP [Microchip Technology], MCP4801T-E/P Datasheet - Page 17

• Manufacturer Part Number: MCP4801T-E/P
• Description: 8/10/12-Bit Voltage Output Digital-to-Analog Converter with Internal VREF and SPI Interface
• Manufacturer: MICROCHIP [Microchip Technology]

4.0
The MCP4801, MCP4811 and MCP4821 are single
channel voltage-output 8-bit, 10-bit and 12-bit DAC
devices, respectively. These devices include rail-to-rail
output amplifier, internal voltage reference, shutdown
and reset-management circuitry. The devices use an
SPI serial communication interface and operate with a
single supply voltage from 2.7V to 5.5V.
The DAC input coding of these devices is straight
binary.
voltage calculation.
EQUATION 4-1:
The ideal output range of each device is:
• MCP4801 (n = 8)
(a) 0.0V to 255/256 * 2.048V when gain setting = 1x.
(b) 0.0V to 255/256 * 4.096V when gain setting = 2x.
• MCP4811 (n = 10)
(a) 0.0V to 1023/1024 * 2.048V when gain setting = 1x.
(b) 0.0V to 1023/1024 * 4.096V when gain setting = 2x.
• MCP4821 (n = 12)
(a) 0.0V to 4095/4096 * 2.048V when gain setting = 1x.
(b) 0.0V to 4095/4096 * 4.096V when gain setting = 2x.
 2010 Microchip Technology Inc.
Note:
Where:
2.048V
Equation 4-1
D
GENERAL OVERVIEW
G
n
n
See the output swing voltage specification in
Section 1.0 “Electrical Characteristics”.
V
=
=
=
=
=
=
=
=
=
OUT
Internal voltage reference
DAC input code
Gain selection
2 for <GA> bit = 0
1 for <GA> bit = 1
DAC Resolution
8 for MCP4801
10 for MCP4811
12 for MCP4821
=
shows the DAC analog output

---------------------------------- -
ANALOG OUTPUT
VOLTAGE (V
2.048V
2
n

D
n


OUT
G
)
1 LSb is the ideal voltage difference between two
successive codes.
calculation of each device.
TABLE 4-1:
4.0.1
Integral Non-Linearity (INL) error is the maximum
deviation between an actual code transition point and
its corresponding ideal transition point once offset and
gain errors have been removed. The two endpoints
method (from 0x000 to 0xFFF) is used for the
calculation.
A positive INL error represents transition(s) later than
ideal. A negative INL error represents transition(s) ear-
lier than ideal.
FIGURE 4-1:
MCP4801/4811/4821
Digital
Input
Code
MCP4801
MCP4811
MCP4821
(n = 10)
(n = 12)
Device
(n = 8)
INL ACCURACY
Figure 4-1
111
110
101
100
011
010
001
000
Selection
LSb OF EACH DEVICE
Gain
Actual
Transfer
Function
1x
2x
1x
2x
1x
2x
Table 4-1
Example for INL Error.
shows the details.
DAC Output
2.048V/4096 = 0.5 mV
INL < 0
4.096V/256 = 16 mV
2.048V/1024 = 2 mV
4.096V/1024 = 4 mV
4.096V/4096 = 1 mV
2.048V/256 = 8 mV
INL < 0
illustrates the LSb
LSb Size
DS22244B-page 17
Ideal Transfer
Function