MIL-M-38510-201 Microcircuits, Digital, 512-Bit, Bipolar, Programmable Read-Only Memory Prom, Monolithic SiliconThis specification covers the detail requirements for monolithic silicon, PROM microcircuits which employ thin film nichrome NiCr resistors as the fusible link or programming element. One product assurance class and a choice of case outlines and lead finishes are provided and are reflected in the complete part number. For this product, the requirements of MIL-M-38510 have been superseded by MIL-PRF-38535, see 6.4.

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MIL-M-38510/201D

4.6     Programming.   Using the test conditions of table IV, the following procedure shall be used for programming the device:

a.  Connect the device as shown on figure 6a, using the fusing generator of figure 6a or the alternate circuit of figure 6b.  The circuit shown on figure 6b can be used in more automated programming systems.

This circuit generates a current pulse which is at the proper voltage and current levels for fast reliable

programming.  The input programming pulse width shall be 750 ±50 milliseconds.  The number of attempts to program a given bit shall be specified in table IV.

b.  To address a particular word in the memory, set the input switches to the binary equivalent of that word, where a logical low level is -5.0 V and a logical high level is an open circuit.  (Do not return to supply.)

All outputs bits ( 80, 81, . . . 87 ) of this word are not available for programming.

c.   With the output current limited (as specified in table IV), apply a negative going current pulse to the pin associated with the first bit to be changed from a logical low level to a logical high level.  This is most easily accomplished by connecting the negative terminal of a variable power supply output pin and manually increasing the voltage to approximately 6.0 volts.

d.  Skipping any bit which is to remain a logical low level, repeat 4.6c for each logical low level in the word being addressed.  Not more than one bit shall be programmed at a time.

e.  Set the next input address and repeat 4.6c and d.  This procedure is repeated for each input address for which a specific output word pattern is desired.  Note that all addresses do not have to be programmed at the same time, nor do all output bits for a given address.  A logical low level can always be changed

to a logical high level, simply be repeating 4.6b and c.  A logical low level, once programmed to a logical high level, cannot be reprogrammed.

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