Hardware Reference
In-Depth Information
The MCP4922 from Microchip is a 12-bit voltage output digital-to-analog converter (DAC)
with a flexible four-wire serial interface. The four-wire serial interface allows glueless interface
to SPI, QSPI, and Microwire serial ports.
The MCP4922 has an output settling time of 4.5
s. A D/A conversion operation is started
by writing a 16-bit serial string that contains 4 control and 12 data bits to the MCP4922. De-
signed for a wide range of supply voltages, the MCP4922 can operate from 2.7 to 5.5 V and is
available in several types of packages including PDIP, SOIC, MSOP, and TSSOP.
μ
The pin assignment and functional block of the MCP4922 are shown in Figure 10.17. The
MCP4922 device utilizes a resistive string architecture, which has the inherent advantages of
low differential nonlinearity (DNL) error, low ratio metric temperature coefficient, and fast
settling time. The MCP4922 includes double-buffered inputs, allowing simultaneous updates
using the LDAC pin.
CS
SDI
SCK
LDAC
V
DD
Interface logic
Input
register A
Input
register B
DAC
A
register
DAC
B
register
V
DD
1
8
V
OUTA
2
7
NC
V
REFA
String
DAC
A
String
DAC
B
3
6
AV
SS
CS
Buffer
Buffer
Gain
logic
Gain
logic
SCK
4
5
V
REFB
V
OUTB
SDI
5
10
6
9
NC
SHDN
8
7
LDAC
NC
V
OUTA
SHDN
V
OUTB
(a) Pin assignment
(B) Functional block diagram
Figure 10.17
■
The MCP4922 DAC pins and block diagram
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