74HC4351DB,112

Overview

The Nexperia 74HC4351DB,112 is an 8-channel analog multiplexer/demultiplexer with address latches in a SO20 (SOT163-1) package. It operates as a single-pole octal-throw switch with three digital select inputs (S0-S2), eight independent I/Os (Yn), and one common I/O (Z). The device supports dual supplies: VCC ranges from 2.0 V to 10.0 V for HC logic, while HCT logic requires 4.5 V to 5.5 V. Analog signals span -5 V to +5 V. Key electrical parameters include a typical ON resistance of 80 Ω at 4.5 V supply and propagation delays up to 15 ns. ESD protection exceeds 2 kV (HBM) and 1 kV (CDM).

Feature Summary

• Integrated address latches allow data storage at select inputs via the latch enable pin.
• Built-in logic level translation enables communication between 5 V logic and ±5 V analog signals.
• Typical 'break before make' switching action prevents signal shorting during channel transitions.
• Inputs feature clamp diodes to interface with voltages exceeding VCC using current limiting resistors.

Applications

• Analog multiplexing and demultiplexing systems
• Digital multiplexing and demultiplexing circuits
• Signal gating applications

Procurement Notes

Verify the ordering suffix

Selection Notes

Select the 74HC variant for wide voltage operation (2.0 V to 10.0 V) and CMOS input levels. Choose the 74HCT variant if TTL-compatible input thresholds are required within a strict 4.5 V to 5.5 V supply range. Ensure the SO20 package fits the PCB layout constraints compared to alternative packages like TSSOP20.

Part Context

This component belongs to the standard 74HC/HCT logic family manufactured by Nexperia. It is functionally compatible with other manufacturers' 74HC4351 devices adhering to JEDEC standard no. 7A. The part serves as a general-purpose analog switch suitable for both digital and low-frequency analog signal routing.

Replacement Considerations

Direct substitutes include the 74HC4351D and 74HCT4351D from Nexperia. Cross-brand equivalents such as the CD4051 or MC14051 offer similar functionality but may differ in speed and drive capability. Verify pinout compatibility and voltage ratings when substituting.

FAQ

How does the latch enable (LE) input affect the select inputs?

When LE is HIGH, the latch is transparent, allowing changes in S0-S2 to immediately update the selected channel. When LE goes LOW, the last state of the select inputs is stored, maintaining the current channel selection regardless of subsequent changes on S0-S2.

What is the purpose of the two enable inputs E1 and E2?

All eight switches are turned off (high impedance) when E1 is HIGH or E2 is LOW. Normal operation requires E1 to be LOW and E2 to be HIGH.

Can this device handle analog signals outside the VCC/VEE rails?

Yes, the device supports a wide analog input voltage range from -5 V to +5 V. However, the absolute maximum rating states that voltages at Yn and Z may not exceed VCC or VEE without risking damage, so external clamping or careful biasing is required for signals beyond the supply rails.