The M54/74HCT240PU, HCT241PU and HCT244PU are high speed CMOS OCTAL BUS BUFFERs fabricated in silicon gate C2MOS technology.
Theyhave the same high speed performance of their non-PU counterpart, plus a unique input topology which incorporates a constant current source for each data input. This results is in a small IIL (-150 µA Typ.) wich can fix any data input in the HIGH Logic Level when it is left floating, thus eliminating the need of external pull-up resistor network.
This feature makes these devices particularly suitable in all applications where a data bus needs to beinterfaced tomanual controls like: rotary selectors, keyboards, dip-switches, etc. The inputs are compatible with TTL, NMOS and CMOS output voltage levels. They achieve the high speed operation similar to equivalent LSTTL while maintaining the CMOS low power dissipation.
All inputs are equipped with protection circuits against static discharge and transient excess voltage.
■ HIGH SPEED
tPD = 14 ns (TYP.) at VCC = 5V
■ LOW POWER DISSIPATION
ICCH = 200 µA (TYP.) at TA = 25 oC
■ COMPATIBLE WITH TTL OUTPUTS
VIH = 2V (MIN.) VIL = 0.8V (MAX)
■ CURRENT SOURCES ON DATA INPUTS
ELIMINATE THE NEED OF EXTERNAL PULLUP RESISTORS
■ OUTPUT DRIVE CAPABILITY
15 LSTTL LOADS
■ SYMMETRICAL OUTPUT IMPEDANCE
|IOH| = IOL = 6 mA (MIN)
■ BALANCED PROPAGATION DELAYS
tPLH = tPHL
■ PIN AND FUNCTION COMPATIBLE