AD561
THE AD561 OFFERS TRUE 10-BIT RESOLUTION OVER
FULL TEMPERATURE RANGE
Accuracy:
Analog Devices defines accuracy as the maximum
deviation of the actual, adjusted DAC output (see page 5) from
the ideal analog output (a straight line drawn from 0 to FS – l
LSB) for any bit combination. The AD561 is laser trimmed to
1/4 LSB (0.025% of FS) maximum error at +25°C for the K
and T versions – 1/2 LSB for the J and S.
Monotonicity:
A DAC is said to be monotonic if the output
either increases or remains constant for increasing digital inputs
such that the output will always be a single-valued function of the
input. All versions of the AD561 are monotonic over their full
operating temperature range.
Differential Nonlinearity:
Monotonic behavior requires that
the differential nonlinearity error be less than
1 LSB both at +25°C and over the temperature range of
interest. Differential nonlinearity is the measure of the variation
in analog value, normalized to full scale, associated with a
1 LSB change in digital input code. For example, for a 10 volt
full scale output, a change of 1 LSB in digital input code should
result in a 9.8 mV change in the analog output (1 LSB = 10 V
×
1/1024 = 9.8 mV). If in actual use, however, a 1 LSB change
in the input code results in a change of only 2.45 mV (1/4 LSB)
in analog output, the differential nonlinearity error would be
7.35 mV, or 3/4 LSB The AD561K and T have a max differen-
tial linearity error of 1/2 LSB.
The differential nonlinearity temperature coefficient must also
be considered if the device is to remain monotonic over its full
operating temperature range. A differential nonlinearity tempera-
ture coefficient of 2.5 ppm/°C could, under worst case condi-
tions for a temperature change of +25°C to +125°C, add 0.025%
(100 2.5 ppm/°C of error). The resulting error could then be
as much as 0.025% + 0.025% = 0.05% of FS (1/2 LSB represents
0.05% of FS). To be sure of accurate performance all versions of
the AD561 are therefore 100% tested to be monotonic over the
full operating temperature range.
ORDERING GUIDE
Figure 1. Chip Bonding Diagram
CONNECTING THE AD561 FOR BUFFERED VOLTAGE
OUTPUT
The standard current-to-voltage conversion connections using
an operational amplifier are shown here with the preferred
trimming techniques. If a low offset operational amplifier
(AD510, AD741L, AD301AL) is used, excellent performance
can be obtained in many situations without trimming. (A 5 mV
op amp offset is equivalent to 1/2 LSB on a 10 volt scale.) If a
25
Ω
fixed resistor is substituted for the 50
Ω
trimmer, unipolar
zero will typically be within
±
1/10 LSB (plus op amp offset),
and full scale accuracy will be within
±
1 LSB. Substituting a
25
Ω
resistor for the 50
Ω
bipolar offset trimmer will give a
bipolar zero error typically within
±
1 LSB.
The AD509 is recommended for buffered voltage-output
applications that require a settling time to
±
1/2 LSB of one
microsecond. The feedback capacitor is shown with the
optimum value for each application; this capacitor is required to
compensate for the 25 picofarad DAC output capacitance.
PIN CONFIGURATION
TOP VIEW
MODEL
1
AD561JD
AD561JN
AD561KD
AD561KN
AD561SD
AD561TD
AD561/883B
TEMP RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
–55°C to +125°C
–55°C to +125°C
–55°C to +125°C
ACCURACY
@ +25 C
±
1/2 LSB max
±
1/2 LSB max
±
1/4 LSB max
±
1/4 LSB max
±
1/2 LSB max
±
1/4 LSB max
*
GAIN T C
(of FS/ C)
80 ppm max
80 ppm max
30 ppm max
30 ppm max
60 ppm max
30 ppm max
*
PACKAGE
OPTION
2
D-16
N-16
D-16
N-16
D-16
D-16
*
NOTES
1
For details on grade and package offerings screened in accordance with MIL-STD-883, refer to the
Analog Devices Military Products Databook or current AD561/883B data sheet.
2
D = Ceramic DIP; N = Plastic DIP.
*Refer to AD561/883B military data sheet.
–4–
REV. A
ROCHESTER [ Rochester Electronics ]
