APPLICATION NOTE 421

Device Characteristics of the DS1045 Dual 4-Bit Programmable Delay Line

Product Description

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.

Table 1. Delay Vs. Programmed Value
Part Number Ouput Delay Value
DS1045-2 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
DS1045-3 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54
DS1045-4 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69
DS1045-5 9 14 19 24 29 34 39 44 49 54 59 64 69 74 79 84
  Progam Values For Each Delay Value
A0 or B0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
A1 or B1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1
A2 or B2 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1
A3 or B3 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1


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.

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.

Table 2. Part Number Table
Part Number Step Zero Delay Max Delay Time Max Delay Tolerance
DS1045-2 9 ± 1 ns 39 ns ±1.8 ns
DS1045-3 9 ± 1 ns 54 ns ±2.5 ns
DS1045-4 9 ± 1 ns 69 ns ±3.3 ns
DS1045-5 9 ± 1 ns 84 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.

Figure 1. DS1045 Block diagram.
Figure 1. DS1045 Block diagram.

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.

Figure 2. DS1045 Circuit diagram.
Figure 2. DS1045 Circuit diagram.

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.

Figure 3. DS1045 Family delay by part type.
Figure 3. DS1045 Family delay by part type.

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 (9ns).

Figure 4. DS1045-2 Rising and falling edge delay times vs. step size.
Figure 4. DS1045-2 Rising and falling edge delay times vs. step size.

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.

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.

Figure 5. Temperature changes (0°C To 70°C).
Figure 5. Temperature changes (0°C To 70°C).

Step Value 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Rising Edge Change (ns) 0.80 0.10 0.20 -0.20 0.40 0.00 0.20 -0.20 0.25 -0.20 0.00 -0.30 0.05 -0.20 -0.10 -0.40
Falling Edge Change (ns) 0.60 0.10 0.20 -0.10 0.20 -0.10 0.20 -0.10 0.20 -0.25 0.10 -0.40 -0.10 -0.30 -0.20 -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.

Figure 6. DS1045 Voltage compensation.
Figure 6. DS1045 Voltage compensation.








































Delay Vs. Temperature: DS1045-3

Side A Rising Edge Signal @ Voltage = 4.75 Volts



Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 8.474 8.629 9.005 9.506 10.063
2 11.587 12.223 12.966 13.769 14.602
3 15.260 15.205 15.667 16.453 17.453
4 17.075 17.678 18.491 19.468 20.632
5 21.084 21.150 21.703 22.675 24.042
6 22.963 23.576 24.496 25.674 27.182
7 26.874 26.910 27.504 28.661 30.333
8 28.820 29.393 30.340 31.674 33.528
9 32.791 32.774 33.409 34.722 36.744
10 34.957 35.502 36.512 38.035 40.193
11 38.597 38.529 39.189 40.651 42.948
12 40.635 41.125 42.133 43.787 46.259
13 44.614 44.486 45.150 46.728 49.368
14 46.891 47.321 48.367 50.188 53.020
15 50.397 50.197 50.868 52.569 55.463
16 52.545 52.878 53.918 55.857 58.977


Side A Rising Edge Signal @ Voltage = 5.00 Volts


Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 8.546 8.594 8.898 9.33 9.835
2 11.539 12.162 12.869 13.619 14.388
3 15.459 15.341 15.622 16.217 17.056
4 17.179 17.716 18.449 19.293 20.333
5 21.45 21.378 21.698 22.413 23.515
6 23.168 23.713 24.491 25.46 26.761
7 27.362 27.241 27.567 28.381 29.717
8 29.151 29.638 30.405 31.46 33.01
9 33.405 33.22 33.535 34.442 36.035
10 35.399 35.852 36.646 37.805 39.591
11 39.357 39.107 39.402 40.381 42.179
12 41.217 41.592 42.342 43.57 45.603
13 45.492 45.185 45.442 46.491 48.56
14 47.597 47.914 48.667 49.989 52.243
15 51.413 51.04 51.272 52.368 54.579
16 53.398 53.622 54.304 55.676 58.13


Side A Rising Edge Signal @ Voltage = 5.25 Volts



Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 8.545 8.579 8.829 9.202 9.658
2 11.542 12.114 12.801 13.515 14.257
3 15.695 15.531 15.681 16.134 16.811
4 17.264 17.814 18.478 19.234 20.153
5 21.815 21.674 21.834 22.348 23.227
6 23.400 23.911 24.598 25.428 26.555
7 27.856 27.666 27.799 28.37 29.406
8 29.512 29.956 30.612 31.476 32.787
9 34.033 33.764 33.863 34.482 35.715
10 35.881 36.304 36.943 37.895 39.354
11 40.136 39.793 39.848 40.509 41.879
12 41.824 42.154 42.759 43.715 45.358
13 46.388 45.981 46.010 46.679 48.235
14 48.349 48.619 49.181 50.196 51.990
15 52.467 51.979 51.963 52.651 54.331
16 54.285 54.453 54.963 55.975 57.906


Side A Falling Edge Signal @ Voltage = 4.75 Volts



Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 8.741 8.901 9.368 9.941 10.558
2 12.066 12.637 13.352 14.115 14.922
3 15.645 15.565 16.071 16.874 17.899
4 17.586 18.14 18.924 19.864 21.012
5 21.306 21.378 21.949 22.954 24.33
6 23.517 24.096 24.944 26.075 27.575
7 27.156 27.195 27.814 29.006 30.682
8 29.296 29.806 30.697 31.968 33.814
9 33.025 33.018 33.677 35.03 37.076
10 35.355 35.81 36.736 38.201 40.341
11 38.887 38.816 39.464 40.95 43.304
12 41.014 41.387 42.317 43.916 46.385
13 44.944 44.822 45.493 47.119 49.784
14 47.186 47.499 48.439 50.169 52.938
15 50.828 50.618 51.28 53.015 55.946
16 52.914 53.122 54.036 55.895 58.934


Side A Falling Edge Signal @ Voltage = 5.00 Volts



Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 8.721 8.817 9.210 9.724 10.300
2 12.031 12.565 13.245 13.967 14.722
3 15.825 15.689 15.994 16.616 17.485
4 17.687 18.185 18.874 19.691 20.699
5 21.681 21.591 21.926 22.667 23.797
6 23.736 24.242 24.943 25.881 27.152
7 27.649 27.514 27.851 28.704 30.083
8 29.638 30.065 30.766 31.783 33.299
9 33.651 33.451 33.787 34.721 36.371
10 35.812 36.206 36.887 37.994 39.729
11 39.638 39.384 39.683 40.678 42.51
12 41.601 41.904 42.547 43.717 45.677
13 45.846 45.512 45.789 46.832 48.914
14 47.913 48.146 48.756 50.001 52.144
15 51.867 51.459 51.682 52.79 55.052
16 53.801 53.903 54.460 55.745 58.141


Side A Falling Edge Signal @ Voltage = 5.25 Volts



Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 8.713 8.76 9.091 9.547 10.079
2 11.987 12.505 13.173 13.856 14.563
3 16.143 15.884 16.05 16.494 17.216
4 17.767 18.269 18.901 19.621 20.528
5 22.07 21.893 22.052 22.578 23.501
6 23.963 24.438 25.058 25.85 26.94
7 28.182 27.936 28.091 28.67 29.769
8 29.992 30.392 30.986 31.807 33.08
9 34.287 33.999 34.111 34.749 36.022
10 36.31 36.652 37.211 38.093 39.511
11 40.423 40.067 40.128 40.775 42.204
12 42.224 42.477 42.985 43.875 45.467
13 46.739 46.318 46.346 47.033 48.62
14 48.669 48.854 49.31 50.238 51.973
15 52.909 52.401 52.379 53.062 54.774
16 54.702 54.754 55.151 56.081 57.944



Delay Vs. Temperature: DS1045-4 (LOT#: 22804, DATE CODE: 4292A1)

The following table indicates the performance of the DS1045-4 Programmable Delay. The plotted data is similar to the plots obtained for the DS1045-3. All steps are monotonic and show consistent variations with voltage and temperature.

VCC=4.75 Volts Rising Edge
Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 7.775 7.923 8.361 8.880 9.450
2 11.547 11.545 11.933 12.640 13.55
3 15.751 16.140 16.656 17.281 18.041
4 19.229 19.264 19.632 20.328 21.270
5 23.533 23.973 24.485 25.097 25.931
6 27.207 27.283 27.637 28.332 29.353
7 31.417 31.844 32.287 32.850 33.697
8 35.129 35.202 35.479 36.124 37.175
9 39.374 39.817 40.226 40.763 41.667
10 43.061 43.172 43.449 44.118 45.229
11 47.382 47.811 48.136 48.597 49.490
12 50.877 51.000 51.213 51.823 52.970
13 55.357 55.797 56.087 56.518 57.462
14 59.099 59.227 59.417 60.014 61.238
15 63.287 63.690 63.842 64.194 65.131
16 67.211 67.337 67.442 67.943 69.168


VCC =5.0 Volts Rising Edge
Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 7.622 7.784 8.169 8.642 9.184
2 11.941 11.878 12.076 12.561 13.347
3 15.584 15.953 16.451 17.022 17.714
4 19.708 19.654 19.791 20.278 21.075
5 23.363 23.816 24.304 24.858 25.596
6 27.671 27.677 27.817 28.3 29.164
7 31.23 31.699 32.142 32.649 33.39
8 35.585 35.626 35.705 36.149 37.005
9 39.171 39.691 40.115 40.599 41.361
10 43.503 43.609 43.698 44.143 45.058
11 47.187 47.737 48.083 48.486 49.233
12 51.306 51.455 51.501 51.89 52.834
13 55.136 55.727 56.058 56.437 57.202
14 59.525 59.706 59.745 60.123 61.101
15 63.073 63.659 63.884 64.182 64.928
16 67.635 67.843 67.822 68.131 69.081



VCC =5.25 Volts Rising Edge
Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 7.510 7.668 8.015 8.453 8.957
2 12.359 12.304 12.378 12.696 13.329
3 15.445 15.82 16.297 16.824 17.465
4 20.203 20.156 20.178 20.452 21.096
5 23.215 23.69 24.175 24.683 25.355
6 28.143 28.19 28.225 28.507 29.174
7 31.064 31.596 32.056 32.529 33.178
8 36.051 36.165 36.159 36.404 37.067
9 39.010 39.614 40.062 40.517 41.17
10 43.933 44.152 44.177 44.420 45.134
11 47.004 47.672 48.098 48.475 49.104
12 51.734 52.003 52.015 52.241 52.949
13 54.945 55.683 56.095 56.447 57.101
14 59.929 60.281 60.306 60.493 61.23
15 62.861 63.646 63.984 64.276 64.886
16 68.064 68.472 68.446 68.577 69.271



VCC =4.75 VOLTS FALLING EDGE
Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 7.996 8.349 8.944 9.58 10.236
2 11.924 11.926 12.359 13.069 13.979
3 16.287 16.674 17.213 17.859 18.638
4 19.568 19.611 20.008 20.705 21.657
5 24.109 24.565 25.077 25.705 26.576
6 27.496 27.529 27.863 28.545 29.537
7 32.092 32.543 32.986 33.566 34.432
8 35.557 35.564 35.813 36.436 37.431
9 39.881 40.374 40.818 41.422 42.346
10 43.588 43.616 43.831 44.436 45.47
11 47.817 48.307 48.66 49.203 50.163
12 51.395 51.414 51.549 52.099 53.154
13 56.12 56.603 56.917 57.417 58.412
14 59.297 59.33 59.456 59.977 61.117
15 63.943 64.415 64.64 65.068 66.065
16 67.238 67.244 67.285 67.73 68.877



VCC =5.00 Volts Falling Edge
Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 7.794 8.145 8.698 9.297 9.912
2 12.311 12.233 12.432 12.945 13.732
3 16.093 16.491 16.994 17.587 18.297
4 20.018 19.957 20.127 20.622 21.442
5 23.88 24.383 24.876 25.46 26.225
6 27.944 27.904 28.026 28.49 29.329
7 31.854 32.387 32.826 33.354 34.114
8 36.017 35.986 36.029 36.429 37.259
9 39.641 40.226 40.672 41.216 42.045
10 44.04 44.051 44.068 44.455 45.315
11 47.564 48.164 48.559 49.044 49.861
12 51.824 51.857 51.821 52.172 53.021
13 55.838 56.478 56.848 57.291 58.132
14 59.709 59.782 59.757 60.099 60.973
15 63.662 64.338 64.627 64.997 65.83
16 67.644 67.735 67.628 67.891 68.808


VCC =5.25 Volts Falling Edge
Program Step Delay (ns)
0°C 25°C 50°C 75°C 100°C
1 7.622 7.94 8.481 9.05 9.649
2 12.668 12.594 12.683 13.016 13.659
3 15.9 16.335 16.822 17.368 18.023
4 20.457 20.417 20.446 20.749 21.411
5 23.694 24.23 24.723 25.263 25.961
6 28.397 28.392 28.393 28.664 29.308
7 31.634 32.24 32.711 33.202 33.885
8 36.456 36.496 36.443 36.661 37.305
9 39.416 40.091 40.579 41.084 41.821
10 44.454 44.558 44.502 44.717 45.384
11 47.314 48.057 48.506 48.966 49.688
12 52.26 52.417 52.335 52.496 53.141
13 55.586 56.39 56.844 57.261 57.261
14 60.119 60.348 60.284 60.437 61.135
15 63.412 64.272 64.682 65.038 65.741
16 68.048 68.321 68.216 68.314 68.996


DS1045-4 Delay Vs. Voltage Characteristics

The following chart indicates how the DS1045-4 delay changes for the positive and negative edges of step 1 and step 16 over voltage variations of 5 volts ±5%. For step 1, the falling edge starts at 7.923 ns and declines to 7.579 ns over an increasing voltage. The rising edge of step 1 follows a similar curve. For step 16, the slope is positive for increasing voltage. The exact values for each device are indicated in the following tables. Characteristics for the DS1045-3 and 5 are similar to the DS1045-4.


DS1045-4 Delay Vs. Voltage/Step

DS1045-3 Step Delay Variation Vs. Voltage
Voltage (volts) 4.75V 5.00V 5.25V
Programming Step 1 Falling Edge 8.629 8.594 8.579
Programming Step 1 Rising Edge 8.901 8.817 8.760
Programming Step 16 Falling Edge 52.878 53.622 55.346
Programming Step 16 Rising Edge 53.122 53.903 55.675


DS1045-4 Step Delay Variation Vs. Voltage
Voltage (volts) 4.75V 5.00V 5.25V
Programming Step 1 Falling Edge 7.923 7.784 7.579
Programming Step 1 Rising Edge 8.349 8.145 7.940
Programming Step 16 Falling Edge 67.337 67.843 68.472
Programming Step 16 Rising Edge 67.244 67.735 68.321


DS1045-5 Step Delay Variation Vs. Voltage
Voltage (volts) 4.75V 5.00V 5.25V
Programming Step 1 Falling Edge 7.817 7.681 7.574
Programming Step 1 Rising Edge 8.213 8.005 7.815
Programming Step 16 Falling Edge 82.506 82.961 82.395
Programming Step 16 Rising Edge 82.958 83.363 83.720


Operating Current Vs. Frequency


ICC Vs. Voltage and Temperature: DS10450-3 @ 4.75 Volts

DS1045-3 @ 4.75 Volts
Frequency ICC (MA) Temperature
0°C 25°C 50°C 75°C 100°C
1 MHz 3.41 3.22 3.02 2.88 2.75
2 MHz 4.11 3.89 3.68 3.54 3.41
10 MHz 9.59 9.15 8.83 8.66 8.52
20 MHz 15.83 15.18 14.86 14.75 14.69
33 MHz 23.65 23.02 22.63 22.34 22.32


DS1045-3 @ 5.00 Volts
Frequency ICC (MA) Temperature
0°C 25°C 50°C 75°C 100°C
1 MHz 3.69 3.48 3.26 3.11 2.97
2 MHz 4.45 4.20 3.98 3.82 3.68
10 MHz 10.37 9.89 9.56 9.35 9.18
20 MHz 17.10 16.37 15.98 15.81 15.77
33 MHz 25.41 24.63 24.34 24.07 23.81


DS1045-3 @ 5.25 Volts
Frequency ICC (MA) Temperature
0°C 25°C 50°C 75°C 100°C
1 MHz 4.02 3.78 3.53 3.37 3.22
2 MHz 4.83 4.55 4.30 4.13 3.98
10 MHz 11.21 10.68 10.31 10.01 9.89
20 MHz 18.44 17.63 17.17 16.96 16.83
33 MHz 27.26 26.29 26.03 25.80 25.53


Test Considerations

The DS1045 is a high speed device and as such care should be exercised when testing. Good ground planes and power supply decoupling techniques should be used. It is also required that pin 2 be connected to VCC. A precision time interval counter is required with test resolution ten times better than the required data measurement.

Test Conditions

Input source: 50 ohms maximum with measurements taken at the 1.5 volt level.
Input signal pulse of 250 ns and a period of 1 ms.
Rise and Fall times of 3 ns between 0.6 and 3.0 volts.
Load Capacitance = 15 pF.

Applications

The ability to use the DS1045 Dual Programmable Delay Line in multiple delay line applications makes it unique in the industry. It not only allows you to reduce inventory cost by having a lower number of parts in stock, but it also affords the designer the ability to improve system performance much later in the design cycle. All of the usual applications for delay lines are applicable to this part, but with much greater flexibility.

Caution

A word of caution is in order when loading the input delay registers with the binary value of the desired delay function. In order to insure that the input signal integrity is maintained after the register has been loaded, the input signal must be allowed to propagate through the DS1045 for at least twice the selected delay value. For example, if you were using the DS1045-3, and selected a binary 8, then you should allow at least 32 ns times 2 or 64 ns before the input integrity is established.