I saw this part on a local market categorized as "unknown parts".

out of curiosity I searched 74HC38540, HCT38540 and HCT38540A with no results. the marking in the first line beside TI logo reads 244 so I searched 74HCT244 which is a well known line driver with 20 pins. but this one has 38 pins.

there are 2 little metal edges around pin 11. so I thought this must be two 74HCT244 ICs connected together and the metal markings indicate pin 1 of the second IC, with common supply pins (pin 10 being GND). any Ideas about this? and if it's two 74HC244 in one case (like NE556?), why with no datasheet and an obstructed marking ?

enter image description here

  • \$\begingroup\$ Just buy new devices or devices with a decent provenance. \$\endgroup\$ – Andy aka Aug 23 at 11:35
  • \$\begingroup\$ Your sleuthing suggestion of a HCT244 variant seems like a good try: consider HCT540 variant as well. \$\endgroup\$ – glen_geek Aug 23 at 12:28
  • \$\begingroup\$ Chinese clone?....... \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Aug 23 at 16:22

The little bits of copper not quite sticking out from the IC are just part of the "lead frame" Here's a picture of some assorted lead frames. Once the chip is attached to the lead frame, and the wires bonded, and the epoxy poured over the chip, the lead frame and the connection leads are cut off, the little exposed bits will usually be connected to the most negative terminal (substrate) , usually the "gnd" pin. The 244 would normally be a date code, but these are 4 digits usually, possibly it's a factory code. It appears to be from Texas instruments, and part of their high speed Cmos interface range.

A part 74HC385 exists, but is obsolete, can't find data sheet. Most likely your part is a factory special intended for the aerospace market or some other defense application (although most MILSPEC parts are in ceramic packages).
Lead frame image

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