Overview
The MC74HC4538ADTR2, produced by onsemi, is a dual precision monostable multivibrator that operates in retriggerable and resettable modes. This device is part of the HC series and is known for its high-speed CMOS logic. Although it is currently discontinued and not recommended for new designs, it remains a significant component in existing systems. The MC74HC4538ADTR2 is compatible with standard CMOS outputs and, with pull-up resistors, can also work with LSTTL outputs. It features conditioned trigger inputs, allowing it to be triggered by either the positive or negative edge of an input pulse, and it produces precision output pulses over a wide range of pulse widths determined by external timing components Rx and Cx.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| VCC (DC Supply Voltage) | −0.5 to +7.0 | V |
| VI (DC Input Voltage) | −0.5 ≤ VI ≤ VCC + 0.5 | V |
| VO (DC Output Voltage) | −0.5 ≤ VO ≤ VCC + 0.5 | V |
| IIK (DC Input Diode Current) | ±20, ±30 mA | mA |
| IOK (DC Output Diode Current) | ±25 mA | mA |
| IO (DC Output Sink Current) | ±25 mA | mA |
| ICC (DC Supply Current per Supply Pin) | ±100 mA | mA |
| IGND (DC Ground Current per Ground Pin) | ±100 mA | mA |
| TSTG (Storage Temperature Range) | −65 to +150 | °C |
| VIH (Minimum High-Level Input Voltage) | 1.5 to 6.0 | V |
| VIL (Maximum Low-Level Input Voltage) | 0 to 1.5 | V |
| tPLH (Maximum Propagation Delay Input A or B to Q) | 175 to 265 ns | ns |
| trr (Minimum Retrigger Time, Input A or B) | 60 to 90 ns | ns |
Key Features
- Trigger Inputs: Can be triggered by either the positive or negative edge of an input pulse.
- Conditioned Trigger Inputs: No restrictions on trigger-input rise and fall times.
- Precision Output Pulse: Output pulse width determined by external timing components Rx and Cx.
- Reset Function: Active low reset inputs force the Q output low and the Q output high, regardless of the state of the output pulse circuitry.
- Compatibility: Compatible with standard CMOS outputs and LSTTL outputs with pull-up resistors.
- Package Options: Available in SOIC-16 and TSSOP-16 packages.
Applications
- Pulse Generation: Used in circuits requiring precise pulse generation, such as in timing and sequencing applications.
- Triggering Circuits: Suitable for use in triggering circuits that require edge-triggered inputs.
- Resettable Circuits: Useful in systems that need resettable multivibrators for control and synchronization.
- High-Speed Logic: Part of high-speed CMOS logic circuits where low power consumption and high speed are critical.
Q & A
- What is the MC74HC4538ADTR2 used for?
The MC74HC4538ADTR2 is used as a dual precision monostable multivibrator in electronic circuits, providing precise output pulses and reset functionality.
- Is the MC74HC4538ADTR2 still available for new designs?
No, the MC74HC4538ADTR2 is discontinued and not recommended for new designs. Contact an onsemi representative for alternative options.
- What are the trigger input conditions for the MC74HC4538ADTR2?
The device can be triggered by either the positive or negative edge of an input pulse, with no restrictions on trigger-input rise and fall times.
- How is the output pulse width determined?
The output pulse width is determined by the external timing components Rx and Cx.
- What is the reset function of the MC74HC4538ADTR2?
The reset function forces the Q output low and the Q output high when a low level is applied to the reset input.
- What are the compatible output types for the MC74HC4538ADTR2?
The device is compatible with standard CMOS outputs and LSTTL outputs with pull-up resistors.
- What are the package options for the MC74HC4538ADTR2?
It is available in SOIC-16 and TSSOP-16 packages.
- What is the maximum DC supply voltage for the MC74HC4538ADTR2?
The maximum DC supply voltage is 7.0 V.
- What is the typical propagation delay from input A or B to Q?
The typical propagation delay ranges from 175 to 265 ns.
- What is the minimum retrigger time for the MC74HC4538ADTR2?
The minimum retrigger time is between 60 to 90 ns.
