ADR395 AD [Analog Devices], ADR395 Datasheet - Page 23

• Manufacturer Part Number: ADR395
• Description: Complete Dual, 16-Bit, High Accuracy, Serial Input, Bipolar Voltage Output DACs
• Manufacturer: AD [Analog Devices]

Preliminary Technical Data
TRANSFER FUNCTION
Table 6 shows the ideal input code to output voltage
relationship for the AD5762R for both offset binary and twos
complement data coding.
Table 6. Ideal Output Voltage to Input Code Relationship for
the AD5762R
Digital Input
Offset Binary Data Coding
MSB
1111
1000
1000
0111
0000
Twos Complement Data Coding
MSB
0111
0000
0000
1111
1000
Figure 40. Simplified Serial Interface of Input Loading Circuitry
V
1111
0000
0000
1111
0000
1111
0000
0000
1111
0000
REFIN
LDAC
SYNC
SCLK
SDIN
1111
0000
0000
1111
0000
1111
0000
0000
1111
0000
INTERFACE
for One DAC Channel
REGISTER
REGISTER
16-BIT
DAC
INPUT
LOGIC
DAC
1111
0001
0000
1111
0000
1111
0001
0000
1111
0000
LSB
LSB
I/V AMPLIFIER
Analog Output
V
+2 V
+2 V
0 V
−2 V
−2 V
V
+2 V
+2 V
0 V
−2 V
−2 V
OUTPUT
OUT
OUT
REFIN
REFIN
REFIN
REFIN
REFIN
REFIN
REFIN
REFIN
SDO
× (32767/32768)
× (1/32768)
× (1/32768)
× (32767/32768)
× (32767/32768)
× (1/32768)
× (1/32768)
× (32767/32768)
V
OUT
Rev. PrA | Page 23 of 33
The output voltage expression for the AD5762R is given by
where:
D is the decimal equivalent of the code loaded to the DAC.
V
ASYNCHRONOUS CLEAR ( CLR )
CLR is a negative edge triggered clear that allows the outputs to
be cleared to either 0 V (twos complement coding) or negative
full scale (offset binary coding). It is necessary to maintain CLR
low for a minimum amount of time (see Figure 2) for the
operation to complete. When the CLR signal is returned high,
the output remains at the cleared value until a new value is
programmed. If at power-on CLR is at 0 V, then all DAC
outputs are updated with the clear value. A clear can also be
initiated through software by writing the command 0x04XXXX
to the AD5762R.
REFIN
V
is the reference voltage applied at the REFA, REFB pins.
OUT
=
−
2
×
V
REFIN
+
4
×
V
REFIN
⎡
⎢
⎣
65536
D
⎤
⎥
⎦
AD5762R