M74HC257B1R

Overview

The M74HC257B1R is a high-speed CMOS quad 2-channel multiplexer with 3-state outputs, fabricated using silicon gate C2MOS technology. It features independent 2-channel multiplexers sharing common SELECT and ENABLE (OE) inputs. The device operates within a supply voltage range of 2V to 6V. Propagation delay from data inputs (A, B) to output (Y) is typically 11ns at 6V with 50pF load, while the delay from SELECT to Y is typically 15ns under the same conditions. Quiescent supply current is maximized at 4μA at 25°C.

Feature Summary

• Provides four independent 2-to-1 non-inverting multiplexing channels with shared selection logic.
• Outputs enter a high-impedance state when the active-low enable input is held high.
• Includes protection circuits on all inputs against static discharge and transient excess voltage.
• Maintains symmetrical output impedance for balanced propagation delays.

Applications

• Data routing in digital communication systems
• Signal selection in measurement instrumentation
• Address decoding in memory subsystems

Procurement Notes

Verify component authenticity through authorized STMicroelectronics distributors or certified partners. Confirm package integrity upon receipt, as DIP-16 units are supplied in tubes. Ensure storage conditions remain within specified limits to prevent moisture damage prior to soldering. Cross-reference ordering codes to match specific packaging requirements.

Selection Notes

Select this component for applications requiring low power dissipation and wide operating voltage flexibility. Verify that the required propagation delay meets system timing constraints at the target supply voltage. Ensure the design accommodates the 3-state output behavior by managing bus contention appropriately during enable transitions.

Part Context

This part belongs to the M74HC257 series of quad multiplexers manufactured by STMicroelectronics. It is functionally compatible with standard 74HC series logic devices. The B1R suffix indicates the DIP-16 through-hole package variant.

Replacement Considerations

Direct pin-compatible substitutes include other manufacturers' 74HC257 variants. Verify logic compatibility and electrical specifications before substitution.