This part is a kind of semiconductor called 74HC157.

Function of this product has HCT157 QUAD 2 CHANNEL MULTIPLEXER HCT158 QUAD 2 CHANNEL MULTIPLEXER INV..

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

M54HCT157/158 M74HCT157/158 HCT157 QUAD 2 CHANNEL MULTIPLEXER HCT158 QUAD 2 CHANNEL MULTIPLEXER (INV.) . . . . . . . HIGH SPEED tPD = 21 ns (TYP.) AT VCC = 5 V LOW POWER DISSIPATION ICC = 4 µA (MAX.) AT TA = 25 °C COMPATIBLE WITH TTL OUTPUTS VIH = 2V (MIN.) VIL = 0.8V (MAX) OUTPUT DRIVE CAPABILITY 10 LSTTL LOADS SYMMETRICAL OUTPUT IMPEDANCE IOH = IOL = 4 mA (MIN.) BALANCED PROPAGATION DELAYS tPLH = tPHL PIN AND FUNCTION COMPATIBLE WITH 54/74LS157/158 B1R (Plastic Package) F1R (Ceramic Package) M1R (Micro Package) C1R (Chip Carrier) ORDER CODES : M54HCTXXXF1R M74HCTXXXM1R M74HCTXXXB1R M74HCTXXXC1R PIN CONNECTIONS (top view) HCT157 DESCRIPTION The M54/74HCT157 and the M54/74HCT158 are high speed CMOS QUAD 2-CHANNEL MULTIPLEXERs fabricated with silicon gate C2MOS technology. [ ... ]

74HC157 PDF Datasheet Download