Level Converter 3.3V naar 5V 4-kanaals (Quad Bus Buffer) SN74HCT125N DIP-14

Beschrijving

• Quadruple bus buffer gates featuring independent line drivers with 3-state outputs
• Inputs Are TTL-Voltage Compatible
• Latch-Up Performance Exceeds 250 mA Per JESD 17
• ESD Protection Exceeds JESD 22
• Example Application: Quad Level-Shifter (3V to 5V)

The AHCT125 devices are quadruple bus buffer gates featuring independent line drivers with 3-state outputs. Each output is disabled when the associated output-enable (OE) input is high. When OE is low, the respective gate passes the data from the A input to its Y output.

To ensure the high-impedance state during power up or power down, OE should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

“Level shifting chips let you connect 3V and 5V devices together safely. This chip is particularly good at converting 3V logic up to 5V. This is in demand especially when connecting some 3V devices such as the Teensy 3 to NeoPixels! Just power the 74AHCT125 with 5V, it will detect 3V logic properly. You can also use it to connect 5V logic out to 3V logic in, that’s when you want to power the 74AHCT125 with 3V, it can safely read 5V logic on the input pins.”

Wat is het verschil tussen de SN74AHCT125N en SN74HCT125N

Goede vraag! De SN74HCT125N en de SN74AHCT125N lijken sterk op elkaar (quadruple bus buffer/line driver met 3-state outputs), maar er zit een belangrijk verschil in snelheid en ingangs­eigenschappen:

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SN74HCT125N

• Familie: HCT = High-speed CMOS, TTL-compatibele inputs.
• Voedingsspanning: typisch 5 V (4.5 – 5.5 V).
• Ingangs­niveaus: TTL-compatibel (herkent al “hoog” bij ~2 V).
• Snelheid: typisch propageringstijd rond 10 ns.

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SN74AHCT125N

• Familie: AHCT = Advanced High-speed CMOS, TTL-compatibele inputs.
• Voedingsspanning: ook 5 V (4.5 – 5.5 V).
• Ingangs­niveaus: TTL-compatibel (net als HCT).
• Snelheid: sneller dan HCT – typisch propageringstijd rond 5 ns.

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Kort samengevat

• Functioneel: Beide chips doen hetzelfde (vier buffers met tri-state).
• Ingangen: Beide accepteren TTL-niveaus (handig bij 3.3 V logica naar 5 V).
• Snelheid: AHCT is de snellere variant van HCT.

Dus: SN74HCT125N = gewone high-speed CMOS, SN74AHCT125N = “advanced” high-speed versie (sneller schakelen, lagere delays).