MAX5122 Maxim, MAX5122 Datasheet - Page 18

• Manufacturer Part Number: MAX5122
• Description: +5V/+3V / 12-Bit / Serial / Force/Sense DACs with 10ppm/C Internal Reference
• Manufacturer: Maxim

The MAX5122/MAX5123 have multiplying capabilities
within the reference input voltage range specifications.
Figure 13 shows a technique for applying a sinusoidal
input to REF, where the AC signal is offset before being
applied to the reference input.
On power-up, the input and DAC registers are cleared to
either zero (RSTVAL = DGND) or midscale (RSTVAL =
+5V/+3V, 12-Bit, Serial, Force/Sense DACs
with 10ppm/°C Internal Reference
Figure 12. Multiple Devices Share One Common Digital Input (DIN)
Figure 13. External Reference with AC Components
18
REFERENCE
500mVp-p
+5V/
+3V
INPUT
AC
______________________________________________________________________________________
SCLK
CS1
CS2
CS3
DIN
26k
10k
Power-Supply and Bypassing
Using an External Reference
+5V/+3V
AGND
DAC
CS
SCLK
DIN
REF
with AC Components
MAX495
MAX5122
MAX5123
I
Considerations
V
DD
MAX5122
MAX5123
DGND
FB
OUT
CS
SCLK
DIN
MAX5122
MAX5123
II
V
capacitor in parallel with a 0.1µF capacitor to AGND.
Minimize lead lengths to reduce lead inductance.
Digital and AC signals coupling to AGND can create
noise at the output. Connect AGND to the highest quali-
ty ground available. Use proper grounding techniques,
such as a multilayer board with a low-inductance
ground plane. Wire-wrapped boards and sockets are
not recommended. If noise becomes an issue, shield-
ing may be required.
TRANSISTOR COUNT: 3308
SUBSTRATE CONNECTED TO AGND
___________________Chip Information
DD
). Bypass the power supply (V
CS
SCLK
DIN
MAX5123
MAX5122
III
Layout Considerations
DD
TO OTHER
SERIAL DEVICES
) with a 4.7µF