Octal bus transceiver; 3-state
• ESD protection:
exceeds 2000 V
exceeds 200 V
exceeds 1000 V
• Balanced propagation delays
• All inputs have a Schmitt-trigger
• Inputs accepts voltages higher than
• For AHC only:
operates with CMOS input levels
• For AHCT only:
operates with TTL input levels
• Specified from
−40 to +85 and +125 °C.
The 74AHC/AHCT245 is a
high-speed Si-gate CMOS device.
The 74AHC/AHCT245 is an octal
transceiver featuring non-inverting
3-state bus compatible outputs in
both send and receive directions.
The 74AHC245/74AHCT245 features
an Output Enable (OE) input for easy
cascading and a send/receive (DIR)
input for direction control.
OE controls the outputs so that the
buses are effectively isolated.
See Note 1.
1. H = HIGH voltage level;
L = LOW voltage level;
X = don’t care;
Z = high-impedance OFF-state.
QUICK REFERENCE DATA
GND = 0 V; Tamb = 25 °C; tr = tf ≤ 3.0 ns.
propagation delay CL = 15 pF;
An to Bn, Bn to An VCC = 5 V
3.5 5.0 ns
CI input capacitance VI = VCC or GND 3.5 3.5 pF
4.0 4.0 pF
power dissipation CL = 50 pF;
12 15 pF
f = 1 MHz;
notes 1 and 2
1. CPD is used to determine the dynamic power dissipation (PD in µW).
PD = CPD × VCC2 × fi + ∑ (CL × VCC2 × fo) where:
fi = input frequency in MHz;
fo = output frequency in MHz;
∑ (CL × VCC2 × fo) = sum of outputs;
CL = output load capacitance in pF;
VCC = supply voltage in Volts.
2. The condition is VI = GND to VCC.
1999 Sep 28