Rainbow Electronics MAX5173 - Manual (Page 14)

MAX5171/MAX5173
Low-Power, Serial, 14-Bit DACs
with Force/Sense Voltage Output
14 ______________________________________________________________________________________
Power-Supply and Layout Considerations
Wire-wrap boards are not recommended. For optimum
system performance, use PC boards with separate
analog and digital ground planes. Connect the two
ground planes together at the low-impedance power-
supply source. Connect the DGND and AGND pins
together at the IC. The best ground connection is
achieved by connecting the DAC’s DGND and AGND
pins together and connecting that point to the system
analog ground plane. If the DAC’s DGND is connected
to the system digital ground, digital noise may get
through to the DAC’s analog portion.
Bypass the power supply with a 4.7µF capacitor in par-
allel with a 0.1µF capacitor to AGND. Minimize the
capacitor lead lengths to reduce inductance. If noise
becomes an issue, use shielding and/or ferrite beads to
increase isolation.
To maintain INL and DNL performance, as well as gain
drift, it is extremely important to provide the lowest pos-
sible reference output impedance at the DAC reference
input pin. INL degrades if the series resistance on the
REF pin exceeds 0.1
Ω
. The same consideration must
be made for the AGND pin.
TO OTHER
SERIAL DEVICES
MAX5171
MAX5173
DIN
SCLK
CS
MAX5171
MAX5173
DIN
SCLK
CS
MAX5171
MAX5173
DIN
SCLK
CS
DIN
SCLK
CS1
CS2
CS3
Figure 9. Multiple MAX5171/MAX5173s Sharing Common DIN and SCLK Lines
TO OTHER
SERIAL DEVICES
MAX5171
MAX5173
DIN
SCLK
CS
MAX5171
MAX5173 MAX5171
MAX5173
DIN DOUT DOUT DOUT
SCLK
CS
DIN
SCLK
CS
Figure 8. Daisy-Chaining MAX5171/MAX5173 Devices