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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There is a separate regulator for the digital Vcc, U These are wired back to back between the two ground levels. These boards were developed for use in Pulsar research. This was required due to the obsolescence of the comparators previously used.
This IC is a quad programmable comparator selected for its low and repeatable input offset voltages. If the signal is more positive than this level, the output will switch low and if more dm7ls374n, it will switch high. The output of the comparator is open collector and is thus virtually vm74ls374n from the input terminals.
54LS374 Datasheet PDF
Secondly, the component pads adjacent to the ACF packages allow for the addition of a capacitor dm74lls374n parallel to the internal pF. This is a low noise dual switched integrator that has a built in precision pF capacitor for integration. 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 adtasheet, and changes at twice the rate of FINGER.
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. The digitiser data board was designed, developed, fabricated and tested by the author. 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.
To describe the operation of the circuit, channel 1 is used as an example. The integration period is determined by the separate control board. The digital signal is finally staticized by U7, 74LS The typical current requirements are:. This is to supplement an incomplete track. This reads data from each board and writes the data to a computer interface along with a count word.
This is an octal D-type flip flop with tri-state outputs. The function of this filter is to block DC signals and to control the overall sensitivity of the integrator.
The shielding is provided by the dattasheet groundplane on the component side of the board. These boards are controlled by one Control Board in the same crate. Test Switches There are two switches on the board selected by jumpers.
The schematic circuit was drawn using OrCAD software. 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.
During operation there is a potential of mV or less between these two lines.
This comprises a 2M resistor package RA1A, and 0. Dtaasheet circuit details and user instructions for the control board are in a separate document.
This power rail separation is to reduce power born noise.
Before each integration commences, the switch is closed to discharge the integration capacitor, C2. There is considerable decoupling throughout the board. An integration is then performed across a precision pF capacitor for a single sample interval. They are provided to facilitate board testing. All digital grounds are linked to this plane.
National Semiconductor – datasheet pdf
The operation is identical for all 64 channels. Nearby C, there are two diodes D1, and D2. This documentation concerns the 64 channel Digitiser Data Boards designed in The signal fed onto the edge connector is passed directly through the high pass filter. Refer to the complete schematic diagram at the end of this section. Following manufacturers’ guidelines, each ACF integrator is decoupled from both rails by 1.
It is a modification datasbeet a previous design of Each comparator package is decoupled from both power rails by 10nF capacitors.
These capacitors are identified on the data board and in the schematic as C through C The signal is passed through a 0. The two unused controls are pulled high by resistors R1 and R2.
There are nine data boards in the crate supplied, thus allowing up to channels to be digitised. Failure to do this could result in data bus contention.