AD7564 Analog Devices, AD7564 Datasheet - Page 8

• Manufacturer Part Number: AD7564
• Description: +3.3 V/+5 V, Low Power, Quad 12-Bit CMOS DAC
• Manufacturer: Analog Devices

Specifications of AD7564

• Resolution (bits): 12bit
• Dac Update Rate: 1.8MSPS
• Dac Settling Time: 550ns
• Max Pos Supply (v): +5.5V
• Single-supply: Yes
• Dac Type: Current Out
• Dac Input Format: Ser

AD7564
TERMINOLOGY
Relative Accuracy
Relative accuracy or endpoint linearity is a measure of the
maximum deviation from a straight line passing through the
endpoints of the DAC transfer function. It is measured after ad-
justing for zero error and full-scale error and is normally ex-
pressed in Least Significant Bits or as a percentage of full-scale
reading.
Differential Nonlinearity
Differential nonlinearity is the difference between the measured
change and the ideal 1 LSB change between any two adjacent
codes. A specified differential nonlinearity of 1 LSB maximum
ensures monotonicity.
Gain Error
Gain error is a measure of the output error between an ideal
DAC and the actual device output. It is measured with all 1s
in the DAC after offset error has been adjusted out and is ex-
pressed in Least Significant Bits. Gain error is adjustable to
zero with an external potentiometer.
Output Leakage Current
Output leakage current is current which flows in the DAC
ladder switches when these are turned off. For the I
terminal, it can be measured by loading all 0s to the DAC and
be measured by loading all 0s to the DAC and measuring the I
current. Minimum current will flow in the I
DAC is loaded with all 1s. This is a combination of the switch
leakage current and the ladder termination resistor current.
The I
Output Capacitance
This is the capacitance from the I
DB15
DB11 DB10 DB9
OUT2
leakage current is typically equal to that in I
DB8
OUT1
DB7
pin to AGND.
DB6
OUT2
DS1
0
0
1
1
Table I. AD7564 Loading Sequence
line when the
OUT1
DB5
OUT1
Table II. DAC Selection
OUT1
.
DB4
DS0
0
1
0
1
–8–
Output Voltage Settling Time
This is the amount of time it takes for the output to settle to a
specified level for a full-scale input change. For the AD7564, it
is specified with the AD843 as the output op amp.
Digital to Analog Glitch Impulse
This is the amount of charge injected into the analog output
when the inputs change state. It is normally specified as the
area of the glitch in either pA-secs or nV-secs, depending upon
whether the glitch is measured as a current or voltage signal. It
is measured with the reference input connected to AGND and
the digital inputs toggled between all 1s and all 0s.
AC Feedthrough Error
This is the error due to capacitive feedthrough from the DAC
reference input to the DAC I
loaded in the DAC.
Channel-to-Channel Isolation
Channel-to-channel isolation refers to the proportion of input
signal from one DAC’s reference input which appears at the
output of any other DAC in the device and is expressed in dBs.
Digital Crosstalk
The glitch impulse transferred to the output of one converter
due to a change in digital input code to the other converter is
defined as the Digital Crosstalk and is specified in nV-secs.
Digital Feedthrough
When the device is not selected, high frequency logic activity on
the device digital inputs is capacitively coupled through the de-
vice to show up at on the I
amp output. This noise is digital feedthrough.
DB3 DB2
Function
DAC A Selected
DAC B Selected
DAC C Selected
DAC D Selected
DB1
DB0
OUT
OUT
pin and subsequently on the op
A1
terminal, when all 0s are
A0
DS1
REV.
DB0
DS0
B