Order Number DM54LSJ, DM54LSW, DM74LSWM or DM74LSN. See Package Number J20A, M20B, N20A or W20A 2. Download Fairchild Semiconductor DM74LSN pdf datasheet file. DM74LSN Octal D-type Transparent Latches And Edge-triggered Flip-flops DM74LS Details, datasheet, quote on part number: DM74LSN.
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This comprises a 2M resistor package RA1A, and 0. Dm74ls734n is a low noise dual switched integrator that has a built in precision pF capacitor for integration.
54LS374 Datasheet PDF
These boards are controlled by one Control Board in the same crate. The works reference is:. The typical current requirements are:. The digitiser data board was designed, developed, fabricated and tested by the author. The integration period is determined by the separate control board.
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This reads data from each board datashret writes the data to a computer interface along with a count word. Failure to do this could result in data bus contention.
All digital grounds are linked to this plane. The operation is identical for all 64 channels. The sign of the output of the integrator is detected by a comparator, the output of which is written onto one bit of a 64 bit data register comprising a D-type latch.
Before each integration commences, the switch is closed to discharge the integration capacitor, C2. The output of the comparator is dm74sl374n collector and is thus virtually isolated from the input terminals. A 27k resistor R5 is in series with the output of the comparator to protect the input of the following stage, since the comparator output switches down to the V rail.
This is an octal D-type flip flop with tri-state outputs. The two unused controls are pulled high by resistors R1 and R2.
This would reduce the gain. Refer to the complete schematic diagram at the end of this section. This IC is a quad programmable comparator selected for its low and repeatable input offset voltages. The signal fed onto the edge connector is passed directly through the high pass filter. After testing the data boards out of the crate, it is important to put these switches back to the ‘Normal’ settings, as illustrated in figure 2 below, before reinserting into the crate.
There is a separate regulator for the digital Vcc, U Manufacturers of the board were Precision Engineering Products Chesterton Ltd, who will retain the production artwork for a limited time. The signal is passed through a 0. This documentation concerns the 64 channel Digitiser Data Boards designed in An integration is then performed across a precision pF capacitor for a single sample interval.
DM74LSN 데이터시트(PDF) – National Semiconductor (TI)
To describe the operation of the circuit, channel 1 is used as an example. This was required due to the obsolescence of the comparators previously used. This is to supplement an incomplete track.
The file is in the same archive, under:. These are wired back to back between the two ground levels. The shielding is provided by the partial groundplane on the component side of the board. They are provided to facilitate board testing. These capacitors are identified on the data board and in the schematic as C through C When the operation is complete, the switch is closed for 2us, discharging the capacitor. It is a modification to a previous design of Following manufacturers’ guidelines, each ACF integrator is decoupled from both rails by 1.
The digital signal is finally staticized by U7, 74LS Datashheet circuit details and user instructions for the control board are in a separate document. Nearby C, there are two diodes D1, and D2. During operation there is a potential of mV or less between these two lines. Secondly, the component pads dayasheet to the ACF packages allow for the addition of a capacitor in parallel to the internal pF.
There is considerable decoupling throughout the board. BANK – signal common to each of the data boards from the control board – pulses low for a period determined by data transfer rate of control board, and changes at twice the rate of FINGER.
DM74LSN Datasheet(PDF) – National Semiconductor (TI)
The schematic circuit was drawn using OrCAD software. This is made up of a network of tracks over the board. There are nine data boards in the crate supplied, thus allowing up to channels to be digitised. If the signal is more positive than this level, the output will switch low and dayasheet more negative, it will switch high. Each comparator package is decoupled from both power rails by 10nF capacitors.
Test Switches There are two switches on the board selected by jumpers.