MCP40D17 Microchip Technology Inc., MCP40D17 Datasheet - Page 45

• Manufacturer Part Number: MCP40D17
• Description: 7-bit Single I 2 C? With Command Code Digital Pot With Volatile Memory In Sc70
• Manufacturer: Microchip Technology Inc.

6.4
Understanding the operational characteristics of the
device’s resistor components is important to the system
design.
6.4.1
6.4.1.1
INL error for these devices is the maximum deviation
between an actual code transition point and its
corresponding ideal transition point after offset and
gain errors have been removed. These endpoints are
from 0x00 to 0x7F. Refer to
Positive INL means higher resistance than ideal.
Negative INL means lower resistance than ideal.
FIGURE 6-5:
© 2009 Microchip Technology Inc.
Digital
Input
Code
Operational Characteristics
ACCURACY
111
110
101
100
011
010
001
000
Integral Non-linearity (INL)
Actual
transfer
function
INL Accuracy.
Digital Pot Output
Figure
INL < 0
INL < 0
6-5.
Ideal transfer
function
6.4.1.2
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 6-6:
6.4.1.3
The ratiometric temperature coefficient quantifies the
error in the ratio R
This is typically the critical error when using a
potentiometer device (MCP40D18) in a voltage divider
configuration.
6.4.1.4
The absolute temperature coefficient quantifies the
error in the end-to-end resistance (Nominal resistance
R
critical error when using a rheostat device (MCP40D17
and
configuration.
Digital
Input
Code
AB
) due to temperature drift. This is typically the
MCP40D19)
111
110
101
100
011
010
001
000
MCP40D17/18/19
Differential Non-linearity (DNL)
Ratiometric temperature coefficient
Absolute temperature coefficient
Actual
transfer
function
AW
Digital Pot Output
DNL Accuracy.
in
/R
WB
an
Narrow code < 1 LSb
due to temperature drift.
adjustable
Wide code, > 1 LSb
Ideal transfer
function
DS22152B-page 45
resistor