PDU54
APPLICATION NOTES
conditions are those for which the delay
ADDRESS UPDATE
tolerance specifications and monotonicity are
guaranteed. The suggested conditions are
those for which signals will propagate through the
unit without significant distortion. The absolute
conditions are those for which the unit will
produce some type of output for a given input.
The PDU54 is a memory device. As such,
special precautions must be taken when
changing the delay address in order to prevent
spurious output signals. The timing restrictions
are shown in Figure 1.
When operating the unit between the
After the last signal edge to be delayed has
appeared on the OUT pin, a minimum time, TOAX
is required before the address lines can change.
This time is given by the following relation:
recommended and absolute conditions, the
delays may deviate from their values at low
frequency. However, these deviations will
remain constant from pulse to pulse if the input
pulse width and period remain fixed. In other
words, the delay of the unit exhibits frequency
and pulse width dependence when operated
beyond the recommended conditions. Please
consult the technical staff at Data Delay Devices
if your application has specific high-frequency
requirements.
,
TOAX = max { (Ai - A i-1) * TINC , 0 }
where A i-1 and Ai are the old and new address
codes, respectively. Violation of this constraint
may, depending on the history of the input signal,
cause spurious signals to appear on the OUT
pin. The possibility of spurious signals persists
until the required TOAX has elapsed.
Please note that the increment tolerances listed
represent a design goal. Although most delay
increments will fall within tolerance, they are not
guaranteed throughout the address range of the
unit. Monotonicity is, however, guaranteed over
all addresses.
INPUT RESTRICTIONS
There are three types of restrictions on input
pulse width and period listed in the AC
Characteristics table. The recommended
PACKAGE DIMENSIONS
24 23 22 21 20 19 18 17 16 15 14 13
.600
.580
MAX.
.005
±
.010
.002
±
1
2
3
4
5
6
7
8
9 10 11 12
1.270 .010
±
Lead Material:
Nickel-Iron alloy 42
.380
TIN PLATE
MAX.
.015 TYP.
.070 MAX.
.018 TYP.
1.100 .010
±
11 Equal spaces
each .100 .010
±
Non-Accumulative
PDU54-xx (Commercial DIP)
PDU54-xxM (Military DIP)
Doc #98004
3/18/98
DATA DELAY DEVICES, INC.
2
Tel: 973-773-2299 Fax: 973-773-9672 http://www.datadelay.com
DATADELAY [ DATA DELAY DEVICES, INC. ]
