Keadic 169Pcs 21 Values Integrated Circuit Chip Assortment Kit, 2.54mm IC Sockets 8 14 16 18 Pins, LM324 LM358 LM386 LM393 LM339 NE5532 NE555 ULN2003 ULN2803 JRC4558 PC817 for Opamp Single Precision

I have tested all the OPAMPs for output voltage swing, slew rate and phase reversal outside the specified common mode input range, and they generally were fairly close to the expected performance with a few exceptions. The 'NE5532P' chips marked with a Texas Instruments (Map of Texas with superimposed lower case 'i') logo are definately fake as they lack the input protection diodes characteristic of this part, and the measured slew rate was under 3V/us rather than the 9V/us typical of this part. The JRC4558 OPAMPs are actually marked JRQ4558D, so a supposedly equivalent part, but I couldn't find a JRQ4558 datasheet anywhere.The switched capacitor voltage converters marked '7660S' with an Intersil logo are also suspect. I attempted a simple negative voltage generator (fig.14 from the Intersil datasheet) using a 9V supply, (75% of its 12V max rating) and the chip failed immediately, drawing approx. 10mA supply current, with the output at a positive voltage and no oscillation on the switched capacitor pins, before I even applied any load. Further testing of a fresh IC in the same circuit with a 5V supply produced the expected negative output. It seems likely that the chips in question are a low grade '7660' clone, with a max. voltage rating under 9V.The NE555P timers worked as expected. The output voltage swing confirmed they are bipolar parts as expected, not CMOS ones.