3D7408 Datasheet, PDF (2/7 Pages) Data Delay Devices, Inc. – MONOLITHIC 8-BIT PROGRAMMABLE DELAY LINE

3D7408
APPLICATION NOTES
The 8-bit programmable 3D7408 delay line
architecture is comprised of a number of delay
cells connected in series with their respective
outputs multiplexed onto the Delay Out pin
(OUT) by the user-selected programming data.
Each delay cell produces at its output a replica of
the signal present at its input, shifted in time.
INPUT SIGNAL CHARACTERISTICS
The Frequency and/or Pulse Width (high or low)
of operation may adversely impact the specified
delay and increment accuracy of the particular
device. The reasons for the dependency of the
output delay accuracy on the input signal
characteristics are varied and complex.
Therefore a Maximum and an Absolute
Maximum operating input frequency and a
Minimum and an Absolute Minimum operating
pulse width have been specified.
OPERATING FREQUENCY
The Absolute Maximum Operating Frequency
specification, tabulated in Table 1, determines
the highest frequency of the delay line input
signal that can be reproduced, shifted in time at
the device output, with acceptable duty cycle
distortion.
The Maximum Operating Frequency
specification determines the highest frequency of
the delay line input signal for which the output
delay accuracy is guaranteed.
To guarantee the Table 1 delay accuracy for
input frequencies higher than the Maximum
Operating Frequency, the 3D7408 must be
tested at the user operating frequency.
Therefore, to facilitate production and device
identification, the part number will include a
custom reference designator identifying the
intended frequency of operation. The
programmed delay accuracy of the device is
guaranteed, therefore, only at the user specified
input frequency. Small input frequency variation
about the selected frequency will only marginally
impact the programmed delay accuracy, if at all.
Nevertheless, it is strongly recommended
that the engineering staff at DATA DELAY
DEVICES be consulted.
OPERATING PULSE WIDTH
The Absolute Minimum Operating Pulse
Width (high or low) specification, tabulated in
Table 1, determines the smallest Pulse Width of
the delay line input signal that can be
reproduced, shifted in time at the device output,
with acceptable pulse width distortion.
The Minimum Operating Pulse Width (high or
low) specification determines the smallest Pulse
Width of the delay line input signal for which the
output delay accuracy tabulated in Table 1 is
guaranteed.
To guarantee the Table 1 delay accuracy for
input pulse width smaller than the Minimum
Operating Pulse Width, the 3D7408 must be
tested at the user operating pulse width.
Therefore, to facilitate production and device
identification, the part number will include a
custom reference designator identifying the
intended frequency and duty cycle of operation.
The programmed delay accuracy of the device is
guaranteed, therefore, only for the user specified
input characteristics. Small input pulse width
variation about the selected pulse width will only
marginally impact the programmed delay
accuracy, if at all. Nevertheless, it is strongly
recommended that the engineering staff at
DATA DELAY DEVICES be consulted.
SPECIAL HIGH ACCURACY
REQUIREMENTS
The Table 1 delay and increment accuracy
specifications are aimed at meeting the
requirements of the majority of the applications
encountered to date. However, some systems
may place tighter restrictions on one accuracy
parameter in favor of others. For example, a
channel delay equalizing system is concerned in
minimizing delay variations among the various
channels. Therefore, because the inter channel
skew is a delay difference, the programmed
delay tolerance may need to be considerably
decreased, while the increment and its tolerance
are of no consequence. The opposite is true for
an under-sampled multi-channel data acquisition
system.
Doc #96003
DATA DELAY DEVICES, INC.
2
12/2/96
Tel: [phone] Fax: [phone] http://www.datadelay.com