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Application Note 3
Device Characteristics of the DS1045
Dual 4-Bit Programmable Delay Line
www.dalsemi.com
PRODUCT DESCIPTION
The DS1045 is a 4-Bit Dual Programmable Delay Line that supports two programmable outputs from a
single input. This CMOS device is capable of producing outputs in binary steps for maximum delays of
up to 84 ns. The selection of one of four standard devices will allow steps of 2, 3, 4, or 5 ns. Table 1
indicates the standard product part for each delay and the maximum delay that can be obtained by each
part.
Each half of the device can be programmed through separate input ports. Inputs A0 through A3 control
side A output while inputs B0 through B3 control side B output. The inputs can either be held in a static
mode or changed dynamically. In the dynamic mode the data enable, setup and hold times must be met.
Typically the delay to a valid output is 15 ns. During the transition period the outputs are in an undefined
state. The pulse widths of the output will be a reproduction of the input delayed by the selected input
delay value. Typical applications are included in the following section.
Each of the outputs is capable of driving 10 standard 74LS type loads. The device is compatible with both
TTL and CMOS and is specified driving a 15 pF load. Input capacitance is 10 pF. All timing
measurements are measured at 1.5 volts with the exception of rise and fall times. Input and output rise
and fall times are measured between 0.6 volts and 2.4 volts.
DELAY VS. PROGRAMMED VALUE
Table 1
PART
NUMBER
DS1045-2
DS1045-3
DS1045-4
DS1045-5
A0 or B0
A1 or B1
A2 or B2
A3 or B3
OUPUT DELAY VALUE
9
9
9
9
0
0
0
0
11
12
13
14
1
0
0
0
13
15
17
19
0
1
0
0
15
18
21
24
1
1
0
0
17
21
25
29
0
0
1
0
19
21
23
25
27
29
31
24
27
30
33
36
39
42
29
33
37
41
45
49
53
34
39
44
49
54
59
64
PROGAM VALUES FOR EACH DELAY VALUE
1
0
1
0
1
0
1
0
1
1
0
0
1
1
1
1
1
0
0
0
0
0
0
0
1
1
1
1
33
45
57
69
0
0
1
1
35
48
61
74
1
0
1
1
37
51
65
79
0
1
1
1
39
54
69
84
1
1
1
1
MAXIMUM OPERATIONAL CHARACTERISTICS
The DS1045 is capable of operation at a very high speed. Consideration should be given with respect to
the minimum pulse width of the input signal when the maximum delay step is selected. For example, if a
delay of a DS1045-5 of 84 ns is selected, then the input pulse width must not be shorter than 9 ns. Table 2
summarizes the minimum pulse widths (step zero delay), maximum delay times and the delay tolerance
for each part number.
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110999
APPLICATION NOTE 3
PART NUMBER TABLE
Table 2
PART NUMBER
DS1045-2
DS1045-3
DS1045-4
DS1045-5
STEP ZERO DELAY
9 ± 1 ns
9 ± 1 ns
9 ± 1 ns
9 ± 1 ns
MAX DELAY TIME
39 ns
54 ns
69 ns
84 ns
MAX DELAY TOLERANCE
±1.8 ns
±2.5 ns
±3.3 ns
±4.1 ns
BLOCK DIAGRAM
The DS1045 is composed of a 16 stage delay line and two sets of digital multiplexers. Each side of the
device can select an appropriate output delay stage by providing an input to the control code specified in
Table 1. The binary value selects the individual stage of delay that becomes the output.
DS1045 BLOCK DIAGRAM
Figure 1
CIRCUIT ANALYSIS
Individual stages may be thought of as RS flip-flops that have a variable capacitive load. Increasing the
capacitive load increases the delay. Similarly, a decrease in the load capacitance decreases the delay. The
operation of the variable capacitive load is similar to the operation of a varistor. The effect of this variable
capacitive loading is that the individual stage set and reset times are precisely controlled. This process
establishes controlled rise and fall times and improve the input to output waveform signal integrity of the
device. The exact capacitive load is established at the factory in the final stages of the manufacturing
process. A simplified schematic of the circuit is shown in Figure 2.
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APPLICATION NOTE 3
DS1045 CIRCUIT DIAGRAM
Figure 2
FAMILY STEP CHARACTERISTICS
Figure 3 indicates the general characteristic of each of the DS1045 devices in this family as a function of
Binary Step Value vs. Delay Time.
DS1045 FAMILY DELAY BY PART TYPE
Figure 3
STEP LINEARITY CHARACTERISTICS
Figure 4 indicates step linearity for rising and falling edge signals. Each of the devices exhibits a virtual
straight line in step linearity. The device specification limits indicate that the starting delay of the zero
position on the chart is the same for each of the devices (9 ns).
This is due to the inherent delay of the first stage. The maximum deviation for any given step is indicated
in Table 2. The maximum step tolerance is specified as
±2.5
ns for a DS1045-3 over the full binary range.
The delay time at step zero is the initial buffer delay of 9 ns
±1
ns.
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APPLICATION NOTE 3
DS1045-2 RISING AND FALLING EDGE DELAY TIMES VS. STEP SIZE
Figure 4
TEMPERATURE CHARACTERISTICS
The DS1045 exhibits excellent temperature characteristics. Figure 5 indicates how the change in delay
times for each step is effected by temperature. The data was taken with a 5.0 volt supply voltage. A
maximum total excursion (delta) of less than
±1
ns for both rising and falling edge signal are indicated.
TEMPERATURE CHANGES (0°C TO 70°C)
Figure 5
°
°
Step Value
Rising Edge
Change (ns)
Falling Edge
Change (ns)
0
0.80
0.60
1
0.10
0.10
2
0.20
0.20
3
-0.20
-0.10
4
0.40
0.20
5
0.00
-0.10
6
0.20
0.20
7
-0.20
-0.10
8
0.25
0.20
9
-0.20
-0.25
10
0.00
0.10
11
-0.30
-0.40
12
0.05
-0.10
13
-0.20
-0.30
14
-0.10
-0.20
15
-0.40
-0.50
VOLTAGE CHARACTERISTICS
The DS1045 is a voltage compensated device whose outputs, both rising and falling edges, vary less than
300 picoseconds with voltage excursions from 4.75 to 5.25 volts. Figure 6 indicates the values for each of
the 16 delay steps.
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APPLICATION NOTE 3
DS1045 VOLTAGE COMPENSATION
Figure 6
DELAY VS. TEMPERATURE
DS1045-3 SIDE A RISING EDGE SIGNAL @ VOLTAGE = 4.75 VOLTS
PROGRAM
STEP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0°C
8.474
11.587
15.260
17.075
21.084
22.963
26.874
28.820
32.791
34.957
38.597
40.635
44.614
46.891
50.397
52.545
25°C
8.629
12.223
15.205
17.678
21.150
23.576
26.910
29.393
32.774
35.502
38.529
41.125
44.486
47.321
50.197
52.878
DELAY (ns)
50°C
9.005
12.966
15.667
18.491
21.703
24.496
27.504
30.340
33.409
36.512
39.189
42.133
45.150
48.367
50.868
53.918
75°C
9.506
13.769
16.453
19.468
22.675
25.674
28.661
31.674
34.722
38.035
40.651
43.787
46.728
50.188
52.569
55.857
100°C
10.063
14.602
17.453
20.632
24.042
27.182
30.333
33.528
36.744
40.193
42.948
46.259
49.368
53.020
55.463
58.977
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