AD660
BIT0
VALID 1
VALID 16
t
DS
SER
t
DH
t
SH
t
SS
BIT1
"1" = MSB FIRST, "0" = LSB FIRST
t
LO
CS
t
HI
t
CLK
LDAC
t
LH
t
LW
Figure 1b. AD660 Serial Load Timing
t
CLR
CLR
t
SET
LBE
"1" = BIP 0, "0" = UNI 0
t
HOLD
Figure 1c. Asynchronous Clear to Bipolar or Unipolar Zero
BIT0
VALID 16
VALID 17
t
DS
SER
BIT 1
(MSB/LSB)
CS
t
PROP
SERIAL
OUT
VALID S
OUT
1
Figure 1d. Serial Out Timing
DEFINITIONS OF SPECIFICATIONS
INTEGRAL NONLINEARITY: Analog Devices defines
integral nonlinearity as the maximum deviation of the actual,
adjusted DAC output from the ideal analog output (a straight
line drawn from 0 to FS–1 LSB) for any bit combination. This
is also referred to as relative accuracy.
DIFFERENTIAL NONLINEARITY: Differential nonlinearity
is the measure of the change in the analog output, normalized to
full scale, associated with a 1 LSB change in the digital input
code. Monotonic behavior requires that the differential linearity
error be greater than or equal to –1 LSB over the temperature
range of interest.
MONOTONICITY: A DAC is monotonic if the output either
increases or remains constant for increasing digital inputs with
the result that the output will always be a single-valued function
of the input.
GAIN ERROR: Gain error is a measure of the output error be-
tween an ideal DAC and the actual device output with all 1s
loaded after offset error has been adjusted out.
OFFSET ERROR: Offset error is a combination of the offset
errors of the voltage-mode DAC and the output amplifier and is
measured with all 0s loaded in the DAC.
REV. A
BIPOLAR ZERO ERROR: When the AD660 is connected for
bipolar output and 10 . . . 000 is loaded in the DAC, the devia-
tion of the analog output from the ideal midscale value of 0 V is
called the bipolar zero error.
DRIFT: Drift is the change in a parameter (such as gain, offset
and bipolar zero) over a specified temperature range. The drift
temperature coefficient, specified in ppm/°C, is calculated by
measuring the parameter at T
MIN
, 25°C and T
MAX
and dividing
the change in the parameter by the corresponding temperature
change.
TOTAL HARMONIC DISTORTION + NOISE: Total har-
monic distortion + noise (THD+N) is defined as the ratio of the
square root of the sum of the squares of the values of the har-
monics and noise to the value of the fundamental input fre-
quency. It is usually expressed in percent (%).
THD+N is a measure of the magnitude and distribution of lin-
earity error, differential linearity error, quantization error and
noise. The distribution of these errors may be different, depend-
ing upon the amplitude of the output signal. Therefore, to be
the most useful, THD+N should be specified for both large and
small signal amplitudes.
–5–
AD [ ANALOG DEVICES ]
