MCP4922-E/ST Microchip Technology, MCP4922-E/ST Datasheet - Page 16

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

Specifications of MCP4922-E/ST

• Number Of Converters: 2
• Package / Case: 14-TSSOP
• 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
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power Dissipation (max): -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MCP4921/4922
4.0
The MCP492X devices are voltage output string DACs.
These devices include input amplifiers, rail-to-rail out-
put amplifiers, reference buffers, shutdown and reset-
management circuitry. Serial communication conforms
to the SPI protocol. The MCP492X operates from 2.7V
to 5.5V supplies.
The coding of these devices is straight binary and the
ideal output voltage is given by Equation 4-1, where G
is the selected gain (1x or 2x), D
input value and n represents the number of bits of
resolution (n = 12).
EQUATION 4-1:
1 LSB is the ideal voltage difference between two
successive codes. Table 4-1 illustrates how to calculate
LSB.
TABLE 4-1:
4.0.1
INL error for these devices is the maximum deviation
between an actual code transition point and its corre-
sponding ideal transition point once offset and gain
errors have been removed. These endpoints are from
0x000 to 0xFFF. Refer to Figure 4-1.
Positive INL means transition(s) later than ideal.
Negative INL means transition(s) earlier than ideal.
DS21897A-page 16
MCP492X
MCP492X
Device
GENERAL OVERVIEW
INL ACCURACY
External V
External V
V
LSB SIZES
V
OUT
REF
LSB SIZE
, GAIN
=
REF
REF
V
-------------------------
REF
, 1x
, 2x
2
N
GD
n
represents the digital
N
V
2 V
REF
LSB SIZE
REF
/4096
/4096
FIGURE 4-1:
4.0.2
DNL error is the measure of variations in code widths
from the ideal code width. A DNL error of zero would
imply that every code is exactly 1 LSB wide.
FIGURE 4-2:
4.0.3
Offset error is the deviation from zero voltage output
when the digital input code is zero.
4.0.4
Gain error is the deviation from the ideal output,
V
Digital
Input
Code
REF
Digital
Input
Code
– 1 LSB, excluding the effects of offset error.
111
110
101
100
011
010
001
000
DNL ACCURACY
OFFSET ERROR
GAIN ERROR
111
110
101
100
011
010
001
000
Actual
transfer
function
Actual
transfer
function
DAC Output
INL Accuracy.
DNL Accuracy.
 2004 Microchip Technology Inc.
DAC Output
INL < 0
Narrow code < 1 LSB
INL < 0
Wide code, > 1 LSB
Ideal transfer
function
Ideal transfer
function