3D7215
APPLICATION NOTES
OPERATIONAL DESCRIPTION
The 3D7215 five-tap delay line architecture is
shown in Figure 1. The delay line is composed
of a number of delay cells connected in series.
Each delay cell produces at its output a replica of
the signal present at its input, shifted in time.
The delay cells are matched and share the same
compensation signals, which minimizes tap-to-
tap delay deviations over temperature and supply
voltage variations.
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
Recommended Maximum
Frequency,
the 3D7215 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.
INPUT SIGNAL CHARACTERISTICS
The Frequency and/or Pulse Width (high or low)
of operation may adversely impact the specified
delay 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
Recommended Maximum
and an
Absolute
Maximum
operating input frequency and a
Recommended Minimum
and an
Absolute
Minimum
operating pulse width have been
specified.
OPERATING PULSE WIDTH
The
Absolute Minimum 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
Recommended Minimum 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
Recommended Minimum Pulse Width,
the
3D7215 must be tested at the user operating
IN
O1
O2
O3
O4
O5
OPERATING FREQUENCY
The
Absolute Maximum 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
Recommended Maximum Frequency
specification determines the highest frequency of
IN O1
O2
O3
O4
O5
25%
25%
25%
25%
20%
20%
20%
20%
20%
Temp & VDD
Compensation
Temp & VDD
Compensation
VDD
Dash numbers < 8
GND
VDD
Dash numbers >= 8
GND
Figure 1: 3D7215 Functional Diagram
Doc #01015
11/8/01
DATA DELAY DEVICES, INC.
Tel: 973-773-2299
Fax: 973-773-9672
http://www.datadelay.com
2
DATADELAY [ DATA DELAY DEVICES, INC. ]
