ad5331bru-reel7 Analog Devices, Inc., ad5331bru-reel7 Datasheet - Page 16

• Manufacturer Part Number: ad5331bru-reel7
• Description: 2.5 V To 5.5 V, 115 Ua, Parallel Interface Single Voltage-output 8-/10-/12-bit Dacs
• Manufacturer: Analog Devices, Inc.

AD5330/AD5331/AD5340/AD5341
SUGGESTED DATABUS FORMATS
In most applications GAIN and BUF are hard-wired. However,
if more flexibility is required, they can be included in a databus.
This enables you to software program GAIN, giving the option
of doubling the resolution in the lower half of the DAC range.
In a bused system, GAIN and BUF may be treated as data inputs
since they are written to the device during a write operation and
take effect when LDAC is taken low. This means that the refer-
ence buffers and the output amplifier gain of multiple DAC
devices can be controlled using common GAIN and BUF lines.
In the case of the AD5330 this means that the databus must be
wider than eight bits. The AD5331 and AD5340 databuses must
be at least 10 and 12 bits wide respectively and are best suited
to a 16-bit databus system.
Examples of data formats for putting GAIN and BUF on a 16-
bit databus are shown in Figure 31. Note that any unused bits
above the actual DAC data may be used for BUF and GAIN.
DAC devices can be controlled using common GAIN and
BUF lines.
The AD5341 is a 12-bit device that uses byte load, so only four
bits of the high byte are actually used as data. Two of the unused
bits can be used for GAIN and BUF data by connecting them
to the GAIN and BUF inputs; e.g., Bits 6 and 7, as shown in
Figures 32 and 33.
In this case, the low byte is written first in a write operation
with HBEN = 0. Bits 6 and 7 of DAC data will be written into
GAIN and BUF registers but will have no effect. The high byte
is then written. Only the lower four bits of data are written into the
DAC high byte register, so Bits 6 and 7 can be GAIN and BUF
data.
LDAC is used to update the DAC, GAIN and BUF values.
BUF
BUF
BUF
X = UNUSED BIT
GAIN
GAIN
GAIN
X
X
X
DATA BUS
X
X
X
X = UNUSED BIT
8-BIT
DB7
BUF GAIN
DB11
X
X
DB6
DB10
X
X
DB
DB5
6
DB9 DB8
DB9 DB8
X
DB
X
7
HIGH BYTE
LOW BYTE
DB4
AD5330
AD5331
AD5340
X
X
BUF
GAIN
LDAC
CLR
CS
WR
HBEN
DB7
DB7
DB7
DB11
DB3
DATA
INPUTS
DB6
DB6
DB6
DB10
DB2
AD5341
DB5
DB5
DB5
DB9
DB1
DB4
DB4
DB4
DB8
DB0
DB3
DB3
DB3
DB2
DB2
DB2
DB1
DB1
DB1
DB0
DB0
DB0
APPLICATIONS INFORMATION
Typical Application Circuits
The AD5330/AD5331/AD5340/AD5341 can be used with a
wide range of reference voltages, especially if the reference inputs
are configured to be unbuffered, in which case the devices offer
full, one-quadrant multiplying capability over a reference range
of 0.25 V to V
fixed, precision reference voltage. Figure 34 shows a typical
setup for the devices when using an external reference connected to
the unbuffered reference inputs. If the reference inputs are unbuf-
fered, the reference input range is from 0.25 V to V
on-chip reference buffers are used, the reference range is reduced.
Suitable references for 5 V operation are the AD780 and REF192.
For 2.5 V operation, a suitable external reference would be the
AD589, a 1.23 V bandgap reference.
Driving V
If an output range of zero to V
tion is to connect the reference inputs to V
not be very accurate, and may be noisy, the devices may be
powered from the reference voltage, for example using a 5 V
reference such as the ADM663 or ADM666, as shown in
Figure 35.
AD589 WITH V
VSET
AD780/REF192
WITH V
ADM663/ADM666
EXT
REF
DD
6V TO 16V
GND
OR
V
GND
V
DD
From the Reference Voltage
DD
IN
IN
V
DD
= 5V
SENSE
V
. More typically, these devices may be used with a
OUT
SHDN
OUT(2)
= 2.5V
0.1 F
0.1 F
0.1 F
10 F
DD
V
V
DD
REF
V
is required, the simplest solu-
AD5330/AD5331/
AD5340/AD5341
REF
10 F
AD5330/AD5331/
AD5340/AD5341
V
DD
GND
DD
= 2.5V TO 5.5V
GND
V
. As this supply may
DD
V
OUT
DD
V
OUT
, but if the