MC14538BFEL

Overview

The MC14538BFEL is a dual precision retriggerable and resettable monostable multivibrator manufactured by onsemi. It operates within a DC supply voltage range of 3.0 Vdc to 18 Vdc and supports an operating temperature range from -55°C to +125°C. The device generates accurate output pulses with widths ranging from 10 μs to 10 s, determined by external timing components RX and CX. It features latched trigger inputs and separate latched reset inputs, allowing triggering from either the positive edge (A input) or negative-going edge (B input).

Feature Summary

• Dual precision monostable multivibrator architecture with independent timing networks for each channel.
• Retriggerable functionality allows pulse width extension upon receiving subsequent valid triggers before the output returns to quiescent state.
• Separate latched reset inputs enable immediate termination of the output pulse generation cycle.
• Capable of driving two low-power TTL loads or one low-power Schottky TTL load over the rated temperature range.

Applications

• Pulse width modulation circuits requiring precise timing control.
• Frequency division and counting applications utilizing retriggerable characteristics.
• Timing delay generation in digital logic systems.

Procurement Notes

Verify the specific ordering suffix EL against official onsemi documentation to confirm package type and reel specifications. Ensure compatibility with SOEIAJ-16 footprint requirements during PCB layout. Confirm that external timing component leakage does not exceed limits for high resistance values to maintain accuracy. Validate supply voltage constraints against system power rails.

Selection Notes

Select this component when dual independent monostable channels are required within a single package. Consider the wide supply voltage range for flexibility in various logic families. Evaluate the need for retriggerable versus non-retriggerable behavior based on application signal characteristics. Verify thermal management requirements for operation up to 125°C ambient temperature.

Part Context

The MC14538B series belongs to onsemi's standard CMOS logic product line. It is pin-for-pin compatible with the MC14528B and CD4528B (CD4098), facilitating direct replacements in existing designs. The BFEL variant specifically denotes the SOEIAJ-16 plastic package configuration.

Replacement Considerations

MC14528B

FAQ

How is the output pulse width determined?

The output pulse width is determined by the values of the external timing resistor (RX) and capacitor (CX), calculated using the formula T = RX × CX.

Can the device be triggered by both rising and falling edges?

Yes, the device can be triggered from the positive edge via the A input or the negative-going edge via the B input.