1. Testing CD74HC4051 part using RIGOL DG1022 signal generator and Tektronix MSO 2024B scope with supplied X10 probes.
2. Test Setup #1 With VCC = +5Vdc, GND Pin = VEE pin = -5Vdc with 0.1uF decoupling capacitors used. Input(Pin 3) driven with signal generator @7Vpp and the
output (pin 13) monitored with scope probe. Input(Pin 3) also monitored with a scope probe.
3. Desired Operation 7Vpp input signal multiplexed to different outputs. 1Hz to 20MHz Bandwidth minimum.
4. Concerning Bandwidth and input impedance. Test #1 The 7Vpp applied by the generator is constant from 1 HZ to 2.5MHz. The signal then begins and
continues rise in amplitude from 2.5MHz to 20MHz. If generator is disconnected from the circuit and its output is monitored, the amplitude remains constant to
20MHz. It appears the input impedance is changing on the CD74HC4051 input pin. Is this normal? Will a low impedance buffer (op-amp) output drive this pin
through frequency and keep the amplitude stable? Note the output pin does follow the input pin in this configuration.
5. Concerning Bandwidth and input impedance. Test #2 (VCC=+5V, GND = 0V (PS Common), VEE=-5V) Can Ground pin be connected to 0V (PS Common) and
maintain a 20MHz or greater bandwidth? A test I performed indicates approximately a 2.5MHz bandwidth in this configuration.
6. If GND and VEE connected is required for bandwidth, what are the conditions for the address and enable inputs? Will they require level shifting?
