MM74HC4538N

Overview

The MM74HC4538N is a dual retriggerable precision monostable multivibrator implemented in advanced silicon-gate CMOS technology. It features Schmitt trigger inputs for both positive and negative edge triggering, allowing unlimited rise and fall times on trigger signals. The device operates within a supply voltage range of 2V to 6V and includes a clear input that resets the output when taken low. Pulse width stability is maintained across wide temperature and supply variations using linear CMOS techniques.

Feature Summary

• Dual retriggerable precision monostable multivibrator with Schmitt trigger inputs
• Compatible with standard CMOS outputs and LSTTL loads via pullup resistors
• Outputs directly interface to CMOS, NMOS, and TTL logic families
• Includes clear/reset function to force Q output low regardless of pulse state

Applications

• Timing delay circuits requiring precise pulse generation
• Debouncing switches or contacts in digital systems
• Pulse width modulation signal conditioning
• Frequency division and counting applications

Procurement Notes

Verify package type N16E (PDIP) matches design requirements. Confirm operating temperature range (-40°C to +85°C) aligns with system specifications. Check supply voltage compatibility (2V-6V). Ensure external timing components RX and CX meet minimum values (RX min 1kΩ, CX min 0pF). Review power-down considerations regarding capacitor discharge through protection diodes.

Selection Notes

Select this component for applications requiring dual independent monostable circuits with high noise immunity. Suitable for designs needing direct interfacing with TTL loads without additional buffering. Consider pin compatibility with CD4528/CD4538 if migrating from older designs. Verify static discharge protection requirements are met by internal diodes to VCC and ground.

Part Context

Part of the 74HC series high-speed CMOS logic family. Manufactured originally by Fairchild Semiconductor, now part of onsemi portfolio. Pin-compatible with CD4528 and CD4538 devices. Uses 145 FETs or 36 equivalent gates per datasheet. Complies with JEDEC Standard No. 7A for CMOS operation characteristics.

Replacement Considerations

Pin-compatible substitutes include CD4528 and CD4538. Verify electrical parameters match specific application needs when substituting. Check manufacturer-specific absolute maximum ratings and operating conditions before replacement.