Overview
The CD74HC221MT, produced by Texas Instruments, is a High-Speed CMOS Logic Dual Monostable Multivibrator with Reset. This integrated circuit is designed to generate a single output pulse of a fixed duration in response to a trigger input. The device features two independent monostable multivibrators, each capable of producing output pulses that can be terminated by a LOW level on the Reset (R) pin. The timing and accuracy of the output pulse are controlled by external components, an resistor (RX) and a capacitor (CX).
Key Specifications
| Parameter | Symbol | Min | Max | Units | |
|---|---|---|---|---|---|
| Supply Voltage | VCC | 2 | 4.5 | 6 | V |
| Input Pulse Width (A) | tWL | 2 | 14 | 21 | ns |
| Input Pulse Width (B) | tWH | 2 | 14 | 21 | ns |
| External Resistance (RX) | - | 500 | - | - | Ω |
| Input Capacitance | CIN | - | - | 10 | pF |
| Power Dissipation Capacitance | CPD | - | - | 166 | pF |
| Operating Temperature Range | - | -55 | - | 125 | °C |
Key Features
- Dual monostable multivibrators with reset, allowing for independent operation of each multivibrator.
- External resistor (RX) and capacitor (CX) control the timing and accuracy of the output pulse.
- Pulse triggering on the B input occurs at a particular voltage level, independent of the rise and fall time of the trigger pulse.
- Trailing Edge triggering (A) and leading-edge-triggering (B) inputs are provided for triggering from either edge of the input pulse.
- Output pulse can be terminated by a LOW level on the Reset (R) pin.
- High-Speed CMOS logic with balanced propagation delay and transition times.
- Significant power reduction compared to LSTTL logic ICs.
- Operates over a supply voltage range of 2V to 6V.
Applications
- Timing and pulse generation in digital circuits.
- Frequency division and counting circuits.
- Sequential logic circuits requiring precise timing.
- Automotive and industrial control systems where reliable timing is crucial.
- Consumer electronics requiring high-speed CMOS logic.
Q & A
- What is the CD74HC221MT?
The CD74HC221MT is a High-Speed CMOS Logic Dual Monostable Multivibrator with Reset produced by Texas Instruments.
- How is the output pulse width controlled in the CD74HC221MT?
The output pulse width is controlled by an external resistor (RX) and an external capacitor (CX).
- What are the triggering options for the CD74HC221MT?
The device provides trailing edge triggering (A) and leading-edge-triggering (B) inputs.
- How can the output pulse be terminated?
The output pulse can be terminated by a LOW level on the Reset (R) pin.
- What is the operating temperature range of the CD74HC221MT?
The operating temperature range is from -55°C to 125°C.
- What is the supply voltage range for the CD74HC221MT?
The supply voltage range is from 2V to 6V.
- What types of packages are available for the CD74HC221MT?
The device is available in various packages including PDIP, SOIC, SOP, and TSSOP.
- Is the CD74HC221MT RoHS compliant?
Yes, the CD74HC221MT is RoHS compliant.
- What is the minimum value of external resistance (RX) required?
The minimum value of external resistance (RX) is typically 500Ω.
- How does the device behave on power-up?
On power-up, the IC is reset.
