Datasheet
MCP4728
DS22187E-page 56 © 2010 Microchip Technology Inc.
FIGURE 7-5: Example of Writing Fast Write Command for Various V
OUT
. V
REF
= V
DD
For All Channels.
1st Byte 2nd Byte
DAC A
Start
3rd Byte
Stop
S1100A2A1A00A011A2A1A001A011A2A1A010A . . . . . . . P
Address Byte
Write Command
Fast Mode
Next DAC Channels
V
OUT
V
REF
D
n
×
()
4096
---------------------------------- G
x
=
V
OUT
A
V
DD
4095
×
()
4096
------------------------------------V
DD
4096 1–
4096
---------------------
⎝⎠
⎛⎞
V
DD
1
1
4096
------------–
⎝⎠
⎛⎞
V
DD
LSB–====
Dn for Channel A = 0FFF (hex) = 4095 (decimal)
(A) Channel A Output:
(B) Channel B Output:
Dn for Channel B = 07FF (hex) = 2047 (decimal)
V
OUT
B
V
DD
2047
×
()
4096
------------------------------------V
DD
2048 1–
4096
---------------------
⎝⎠
⎛⎞
V
DD
2
-------------1
2
4096
------------–
⎝⎠
⎛⎞
V
DD
2
-------------LSB–====
(C) Channel C Output:
Dn for Channel C = 03FF (hex) = 1023 (decimal)
V
OUT
C
V
DD
1023
×
4096
---------------------------------- V
DD
1024 1–
4096
---------------------
⎝⎠
⎛⎞
V
DD
4
-------------1
4
4096
------------–
⎝⎠
⎛⎞
V
DD
4
-------------LSB–====
(D) Channel D Output:
Dn for Channel D = 01FF (hex) = 511 (decimal)
V
OUT
D
V
DD
511
×
4096
------------------------------- V
DD
512 1–
4096
------------------
⎝⎠
⎛⎞
V
DD
8
-------------1
8
4096
------------–
⎝⎠
⎛⎞
V
DD
8
-------------LSB–====
DAC A Input Code =
001111-11111111
DAC B Input Code = 000111-11111111
DAC C Input Code = 000011-11111111
DAC D Input Code = 000001-11111111
The following example shows the expected analog outputs with the corresponding DAC input codes: