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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Music Quest – PC MIDI Card – Flytrap Gear Wiki
Full circuit details and user instructions for the control board are in a separate document. Failure to do this could result in data bus contention. It is a modification to a previous design of This comprises a 2M resistor package RA1A, and 0. When dtaasheet operation is complete, the switch is closed for 2us, discharging the capacitor. To describe the operation of the circuit, channel 1 is used as an example.
This is an octal D-type flip flop with tri-state outputs. This would reduce the gain. An dm74ls374 is then performed across a precision pF capacitor for a single sample interval. The integration period is determined by the separate control board.
There are nine data boards in the crate supplied, thus allowing up to channels to be digitised. These are wired back to back between the two ground levels. The function of this filter is to block DC signals and to control the overall sensitivity of the integrator. Nearby C, there are two diodes D1, and D2.
Manufacturers of the board were Precision Engineering Products Chesterton Ltd, who will retain the production artwork for a limited time. The typical current requirements are:. This IC is a quad programmable comparator selected for its low and repeatable input offset voltages. The shielding is provided by the partial groundplane on the component side of the board.
Secondly, the component pads adjacent to the ACF packages allow for the addition of a capacitor in parallel to the internal pF. These boards are controlled by one Control Board in the same crate.
This datashdet concerns the 64 channel Digitiser Data Boards designed in There is a separate regulator for the digital Vcc, U Before each integration commences, the switch is closed to discharge the integration capacitor, C2.
Refer to the complete schematic diagram at the end of this section.
The operation is identical for all 64 channels. They are provided to facilitate board testing. These capacitors are identified on the data board and in the schematic as C through C All digital grounds are linked to this plane.
DM74LSN/A+ Datasheet – Flip-Flop from National Semiconductor
If the signal is more positive than this level, the output will switch low and if more negative, it will switch high. There is considerable decoupling throughout the board.
The signal is passed through a 0. This power rail separation is to reduce power born noise. Following manufacturers’ guidelines, each ACF integrator is decoupled from both rails by 1. This is a low noise dual switched integrator that has a built in precision pF capacitor for integration. This is made up of a network of tracks over the board.
This reads data from each board and writes the data to a computer interface along with a count word. BANK – signal common to each of the data boards from the control board – datashret low for a period determined by data transfer rate of control board, and changes at twice the rate of FINGER.
After testing the vatasheet 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. The schematic circuit was drawn using OrCAD software.
54LS374 Datasheet PDF
Test Switches There are two switches datasheeg the board selected by jumpers. 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.
The file is in the same archive, under:. The digital signal is finally staticized by U7, 74LS This was required due to the obsolescence of the comparators previously used.
These boards were developed for use in Pulsar research.
The works reference is:. This is to supplement an incomplete track. The output of the comparator is open collector and is thus virtually isolated from the input terminals.
Each comparator package is decoupled from both power rails by 10nF capacitors. The two unused controls are pulled high by resistors R1 and R2. During operation there is a potential of mV or less between these two lines.
The digitiser data board was designed, developed, fabricated and tested by the author. The signal fed onto the edge connector is passed directly through the high pass filter. 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.