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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The schematic circuit was datasyeet using OrCAD software. This IC is a quad programmable comparator selected for its low and repeatable input offset voltages. Before each integration commences, the switch is closed to discharge the integration capacitor, C2. The shielding is provided by the partial groundplane on the component side of the board. Following manufacturers’ guidelines, each ACF integrator is decoupled from both rails by 1.

The digital signal is finally staticized by U7, 74LS The sign of the output of the integrator is detected by a comparator, the output of which is written onto one bit of xatasheet 64 bit data register comprising a D-type latch. Full circuit details and user instructions for the control board are in a separate document.

DM74LS374N 数据手册 ( 数据表 ) – Fairchild Semiconductor

Manufacturers of the board were Precision Engineering Products Chesterton Ltd, who will retain the production artwork for a limited time. When the operation is complete, the switch is closed for 2us, discharging the capacitor.

This would reduce the gain. This power rail separation is to reduce dn74ls374n born noise. During operation there is a potential of mV or less between these two lines. These capacitors are identified on the data board and in the schematic as C through C These are wired back to back between the two ground levels. This is to supplement an incomplete track. There is considerable decoupling throughout the board. The integration period is determined by the separate control board.


Nearby C, there are two diodes D1, and D2. The typical current requirements are:. These boards are controlled by one Control Board in the same crate.

DM74LSN/A+ Datasheet – Flip-Flop from National Semiconductor

This was required due to the obsolescence of datahseet comparators previously used. This documentation concerns the 64 channel Digitiser Data Boards designed in All digital grounds are linked to this plane. This is made up of a network of tracks over the board.

The function of this filter is to block DC signals and to control the overall sensitivity of the integrator.

There are nine data boards in the crate supplied, thus allowing up to channels to be digitised. Refer to the complete schematic diagram at the end of this section. It is a modification to a previous design of This comprises a 2M resistor package RA1A, and 0.

Stock/Availability for: DM74LSO2N

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 a low noise dual switched integrator that has a built in precision pF capacitor for integration. The two unused controls are pulled high by resistors R1 and R2.

These boards were developed for use in Pulsar research. 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. The signal fed onto the edge connector is passed directly dataseet the high pass filter. Test Switches There are two switches on the board selected by jumpers. Each comparator package is decoupled from both power rails by 10nF capacitors.

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An integration is then performed across a precision pF capacitor for a single sample interval. To describe the operation of the circuit, channel 1 is used as an example.

The output of the comparator is open collector and is thus virtually isolated from the input terminals.

Failure to do this could result in data bus contention. The file is in the same archive, under:. Secondly, the component pads adjacent to the ACF datassheet allow for the addition of a capacitor in parallel to the internal pF. This reads data from each board and writes the data to a computer interface along with a count word.

After testing the data boards out of the crate, it is important to put these switches back to the datasheey settings, as illustrated in figure 2 below, before reinserting into the crate.

They are provided to facilitate xatasheet testing. The operation is identical for all 64 channels. This is an octal D-type flip flop with tri-state outputs. The signal is passed through a 0. The works reference is:. The digitiser data board was designed, developed, fabricated and tested by the author. There is a separate regulator for the digital Vcc, U If the signal is more positive than this level, the output will switch low and if more negative, it will switch high.