Overview
The CD74HC4538QPWRQ1 is a dual retriggerable/resettable precision monostable multivibrator produced by Texas Instruments. This high-speed CMOS logic device is specifically designed for fixed-voltage timing applications and is qualified for automotive use. It features two independent monostable multivibrators, each capable of generating a wide range of output pulse widths controlled by external resistors and capacitors. The device is known for its balanced propagation delay and transition times, significant power reduction compared to LSTTL logic ICs, and high noise immunity.
Key Specifications
| Parameter | Min | Typ | Max | Unit | Conditions |
|---|---|---|---|---|---|
| VCC Supply Voltage | -0.5 | 7 | V | ||
| Input Clamp Current (VI < -0.5V or VI > VCC + 0.5V) | ±20 | mA | |||
| Output Clamp Current (VO < -0.5V or VO > VCC + 0.5V) | ±20 | mA | |||
| Switch Current per Output Pin | ±25 | mA | VO > -0.5V or VO < VCC + 0.5V | ||
| Maximum Junction Temperature | 150 | °C | |||
| Storage Temperature Range | -65 | 150 | °C | ||
| Operating Free-Air Temperature | -40 | 125 | °C | ||
| Input Transition Time (Rise and Fall) | 0 | 1000 | ns | VCC = 2V | |
| External Timing Resistor (RX) | 5 kΩ | ||||
| External Timing Capacitor (CX) | 0 | F | |||
| Propagation Delay (A, B to Q or Q) | 43 | 54 | 64 | ns | VCC = 6V, CL = 50 pF |
Key Features
- Qualified for automotive applications with retriggerable/resettable capability.
- Trigger and reset propagation delays independent of RX and CX.
- Triggering from the leading or trailing edge of the input pulse.
- Q and Q buffered outputs available.
- Separate resets for each monostable multivibrator.
- Wide range of output pulse widths adjustable via external resistor (RX) and capacitor (CX).
- Schmitt-Trigger input on A and B inputs for improved noise immunity.
- Retrigger time independent of CX.
- Fanout capability: standard outputs support 10 LSTTL loads, bus driver outputs support 15 LSTTL loads.
- Significant power reduction compared to LSTTL logic ICs.
- Operating voltage range: 2V to 6V.
- High noise immunity: NIL or NIH = 30% of VCC at VCC = 5V.
Applications
The CD74HC4538QPWRQ1 is suitable for a variety of applications, particularly in the automotive sector due to its automotive qualification. It can be used in:
- Timing and pulse generation circuits.
- Automotive control systems requiring precise timing signals.
- Industrial control systems where reliable and adjustable timing is necessary.
- Consumer electronics that require high noise immunity and low power consumption.
- Any application requiring dual independent monostable multivibrators with retriggerable/resettable capabilities.
Q & A
- What is the CD74HC4538QPWRQ1 used for?
The CD74HC4538QPWRQ1 is a dual retriggerable/resettable precision monostable multivibrator used for generating precise timing signals in various applications, especially in the automotive sector.
- What is the operating voltage range of the CD74HC4538QPWRQ1?
The operating voltage range is from 2V to 6V.
- How are the output pulse widths controlled in the CD74HC4538QPWRQ1?
The output pulse widths are controlled by external resistors (RX) and capacitors (CX).
- Does the CD74HC4538QPWRQ1 support both leading and trailing edge triggering?
- What is the significance of Schmitt-Trigger inputs in the CD74HC4538QPWRQ1?
Schmitt-Trigger inputs provide improved noise immunity.
- What is the maximum junction temperature for the CD74HC4538QPWRQ1?
The maximum junction temperature is 150°C.
- How many LSTTL loads can the standard outputs of the CD74HC4538QPWRQ1 drive?
The standard outputs can drive up to 10 LSTTL loads.
- What is the retrigger time independence in the CD74HC4538QPWRQ1?
The retrigger time is independent of the external capacitor (CX).
- Is the CD74HC4538QPWRQ1 qualified for automotive applications?
- What are the package options available for the CD74HC4538QPWRQ1?
The device is available in SOIC (16-pin) and TSSOP (16-pin) packages.
