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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Test Switches There are two switches on datwsheet board selected by jumpers. The shielding is provided by the partial groundplane on the component side of the board. This documentation concerns the 64 channel Digitiser Data Boards designed in The file is in the same archive, under:. The signal is passed through a 0.
An integration is then performed across a precision pF capacitor for a single sample interval. When the operation is complete, the switch is closed for 2us, discharging the capacitor. During operation there is a potential of mV or less between these two lines.
This is to supplement an incomplete track. These capacitors are identified on the data board and in the schematic as C through C Nearby C, there are two diodes D1, and D2. The sign of the output of the integrator is detected by a comparator, the output of which is written onto one bit of dwtasheet 64 bit data register comprising a D-type latch.
This would reduce the gain.
Fairchild Semiconductor – DM74LSN PDF 数据手册 , DM74LSN 数据表 – DataSheetBank
There are nine data boards in the crate supplied, thus allowing up to channels to be digitised. All digital grounds are linked to this plane. This is an octal D-type flip flop with tri-state outputs. Following manufacturers’ guidelines, each ACF integrator datashset decoupled from both rails by 1.
The dm7l4s374n period is determined by the separate control board. The signal fed onto the edge connector is passed directly through the high pass filter.
There is a separate regulator for the digital Vcc, U This is a low noise dual switched integrator that has a built in precision pF capacitor for integration. It is a modification to a previous design of Failure datasheeg do this could result in data bus contention.
Before each integration commences, the switch is closed to discharge the integration capacitor, C2. This was required due to the obsolescence of the comparators previously used. The dm74l374n circuit was drawn using OrCAD software. Refer to the complete schematic diagram at the end of this section. The works reference is:.
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 reads data from each board and writes the data to a computer interface along with a count word.
This comprises a 2M resistor package RA1A, and 0. Full circuit details and user instructions for the control board are in a separate document. 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.
DM74LSN Datasheet PDF – National ->Texas Instruments
They are provided to facilitate board testing. The typical current requirements are:.
These boards are controlled by one Control Board in the same crate. The digitiser data board was designed, developed, fabricated and tested by the author. The output of the comparator is open collector and is thus virtually isolated from the input terminals.
This power rail separation is to reduce power born noise. After testing the data boards datasheef of the crate, it is important to put these switches back to the ‘Normal’ settings, as dahasheet in figure 2 below, before reinserting into the crate. The digital signal is finally staticized by U7, 74LS This is made up of a network of tracks over the board.
The two unused controls are pulled high by resistors R1 and R2. If the signal is more positive than this level, the output will switch low and if more negative, it will switch high. These are wired back to back between the two ground levels.