AD5532-3 AD [Analog Devices], AD5532-3 Datasheet - Page 15

• Manufacturer Part Number: AD5532-3
• Description: 32-Channel, 14-Bit Voltage-Output DAC
• Manufacturer: AD [Analog Devices]

APPLICATION CIRCUITS
AD5532 in a Typical ATE System
The AD5532 is ideally suited for use in Automatic Test Equipment.
Several DACs are required to control pin drivers, comparators,
active loads and signal timing. Traditionally, sample-and-hold
devices were used in this application.
The AD5532 has several advantages: no refreshing is required,
there is no droop, pedestal error is eliminated and there is no
need for extra filtering to remove glitches. Overall a higher level
of integration is achieved in a smaller area (see Figure 24).
Typical Application Circuit (SHA Mode)
The AD5532 can be used to set up voltage levels on 32 channels
as shown in the circuit below. An AD780 provides the 3 V refer-
ence for the AD5532, and for the AD5541 16-bit DAC. A simple
3-wire interface is used to write to the AD5541. The DAC output
is buffered by an AD820. It is essential to minimize noise on V
and REFIN when laying out this circuit.
SCLK
GENERATION
AND INHIBIT
DIN
CS
PATTERN
STORED
PERIOD
TIMING
DELAY
DATA
DACs
AND
AV
CC
AD5541*
AD780*
SYSTEM BUS
*ADDITIONAL PINS OMITTED FOR CLARITY
REF
V
OUT
FORMATTER
COMPARE
REGISTER
DAC
DAC
DAC
AD820
ACTIVE
DRIVER
LOAD
V
COMPARATOR
DD
DAC
DAC
MEASUREMENT
V
OFFS_IN
OFFS_OUT
REFIN
SCLK DIN
PARAMETRIC
IN
AV
AD5532*
CC
UNIT
DV
DAC
DAC
CC
SYNC
V
SS
SYSTEM BUS
DUT
V
OUT
0–31
IN
POWER SUPPLY DECOUPLING
In any circuit where accuracy is important, careful consideration
of the power supply and ground return layout helps to ensure
the rated performance. The printed circuit board on which the
AD5532 is mounted should be designed so that the analog and
digital sections are separated, and confined to certain areas of
the board. If the AD5532 is in a system where multiple devices
require an AGND-to-DGND connection, the connection should
be made at one point only. The star ground point should be
established as close as possible to the device. For supplies with
multiple pins (V
together. The AD5532 should have ample supply bypassing of
10 µF in parallel with 0.1 µF on each supply located as close to
the package as possible, ideally right up against the device. The
10 µF capacitors are the tantalum bead type. The 0.1 µF capacitor
should have low Effective Series Resistance (ESR) and Effective
Series Inductance (ESI), like the common ceramic types that
provide a low impedance path to ground at high frequencies, to
handle transient currents due to internal logic switching.
The power supply lines of the AD5532 should use as large a trace
as possible to provide low impedance paths and reduce the
effects of glitches on the power supply line. Fast switching signals
such as clocks should be shielded with digital ground to avoid
radiating noise to other parts of the board, and should never be
run near the reference inputs. A ground line routed between
the D
(not required on a multilayer board as there will be a separate
ground plane, but separating the lines will help). It is essential
to minimize noise on V
Avoid crossover of digital and analog signals. Traces on opposite
sides of the board should run at right angles to each other. This
reduces the effects of feedthrough through the board. A microstrip
technique is by far the best, but not always possible with a double-
sided board. In this technique, the component side of the board
is dedicated to ground plane while signal traces are placed on
the solder side.
IN
and SCLK lines will help reduce crosstalk between them
SS
, V
DD
, AV
IN
and REFIN lines.
CC
) it is recommended to tie those pins
AD5532