M38510/31402B2A

Multivibrators Overview

The M38510/31402B2A is a dual monostable multivibrator manufactured by Texas Instruments under the SN54221 designation. It operates within a supply voltage range of 4.5 V to 5.5 V and supports an operating temperature range of -55°C to 125°C. The device features Schmitt-trigger inputs for noise immunity and allows pulse width adjustment from 35 ns to maximum limits via external RC components. It provides TTL-compatible outputs with overriding clear functionality.

Multivibrators Feature Summary

• Dual monostable multivibrator architecture with independent timing control
• Schmitt-trigger B input ensures jitter-free operation from slow transitions
• Internal compensation maintains pulse stability across voltage and temperature variations
• Overriding clear input terminates output pulses immediately

Multivibrators Applications

• Timing generation in military-grade digital systems
• Pulse stretching and shaping circuits
• DC-triggered reset signal generation
• Replacement for SN54123/SN74123 retriggerable multivibrators

Multivibrators Procurement Notes

Verify that the component meets MIL-PRF-38535 Class B requirements. Confirm the package type matches system constraints, as this part number corresponds to the LCCC (FK) variant. Ensure compatibility with existing PCB footprints designed for SN54221 devices. Validate that external timing components support the required jitter-free capacitance and resistance ranges.

Multivibrators Selection Notes

Select this component when high pulse-width stability and wide temperature operation are required. It serves as a direct pin-compatible replacement for SN54123 or SN74123 devices, provided the capacitor polarity is adjusted. Choose this over LS variants if higher drive current and faster switching speeds are necessary for the application.

Multivibrators Part Context

This part belongs to the SN54221 family of dual monostable multivibrators. It shares electrical characteristics with the SN54121 but offers identical pinouts to the SN54123. The device is designed for robust performance in harsh environments, featuring internal latching circuitry for high immunity to supply noise.

Multivibrators Replacement Considerations

SN54221J

Multivibrators FAQ

Can this device replace an SN54123?

Yes, it has identical pin assignments to the SN54123. However, the capacitor polarity must be reversed when substituting.

What is the minimum trigger rate supported?

The B input supports transition rates as slow as 1 V/s due to its Schmitt-trigger circuitry.