Overview
The CD74HC123E is a high-speed CMOS logic dual retriggerable monostable multivibrator with resets, produced by Texas Instruments. This device is part of the 74HC series and is designed for use in a wide range of digital circuits. It features two independent monostable multivibrators, each capable of generating a single output pulse of a specified duration in response to a trigger input. The device is retriggerable, meaning the output pulse can be extended by additional trigger inputs. The CD74HC123E operates over a temperature range of -55°C to 125°C and is available in a 16-pin PDIP package.
Key Specifications
| Parameter | Symbol | Test Conditions | Min | Max | Units | |
|---|---|---|---|---|---|---|
| DC Supply Voltage | VCC | - | 2 | - | 6 | V |
| High Level Input Voltage | VIH | - | 1.5 | - | 2 | V |
| Low Level Input Voltage | VIL | - | 0.5 | - | 0.5 | V |
| High Level Output Voltage (CMOS Loads) | VOH | - | 1.9 | - | 1.9 | V |
| Low Level Output Voltage (CMOS Loads) | VOL | 0.02 | - | 0.1 | V | |
| Input Leakage Current | II | - | ±0.1 | - | ±1 | µA |
| Quiescent Device Current | ICC | 0 | - | 8 | µA | |
| Trigger Propagation Delay (A, B, R to Q) | tPLH | - | 60 | - | 90 | ns |
| Output Pulse Width (RX = 10KΩ, CX = 10nF) | tW | 38.7 | - | 51.3 | µs |
Key Features
- High-speed CMOS logic dual retriggerable monostable multivibrators with resets.
- Retriggerable, allowing the output pulse to be extended by additional trigger inputs.
- Trailing edge triggering (A) and leading edge triggering (B) inputs.
- Reset input (R) to terminate the output pulse.
- External resistor (RX) and capacitor (CX) control the timing and accuracy of the output pulse.
- Direct LSTTL input logic compatibility for HCT types.
- CMOS input compatibility with low input current (Il ≤ 1µA at VOL, VOH).
- Operating temperature range: -55°C to 125°C.
- Available in 16-pin PDIP package.
Applications
- Digital timing and pulse generation circuits.
- Frequency dividers and counters.
- Pulse width modulation and demodulation.
- Sequential logic circuits requiring precise timing.
- Aerospace, automotive, and industrial control systems where high reliability and wide temperature range are necessary.
Q & A
- What is the CD74HC123E used for?
The CD74HC123E is used as a dual retriggerable monostable multivibrator with resets, generating single output pulses of specified durations in response to trigger inputs.
- What is the operating temperature range of the CD74HC123E?
The operating temperature range is -55°C to 125°C.
- How is the output pulse width controlled in the CD74HC123E?
The output pulse width is controlled by an external resistor (RX) and an external capacitor (CX).
- Can the CD74HC123E be retriggered?
Yes, the CD74HC123E is retriggerable, allowing the output pulse to be extended by additional trigger inputs.
- What types of triggering inputs does the CD74HC123E support?
The device supports trailing edge triggering (A) and leading edge triggering (B) inputs.
- How is the output pulse terminated in the CD74HC123E?
The output pulse can be terminated by a LOW level on the Reset (R) pin.
- What is the typical high-level output voltage for CMOS loads?
The typical high-level output voltage for CMOS loads is 1.9V.
- What is the input leakage current of the CD74HC123E?
The input leakage current is typically ±0.1µA.
- What is the quiescent device current of the CD74HC123E?
The quiescent device current is typically 8µA.
- What package types are available for the CD74HC123E?
The CD74HC123E is available in a 16-pin PDIP package.
