Rochester Electronics, LLC 74ACTQ245MTC-G

A direction input selects data flow between the A and B eight-bit ports; an output-enable input can disconnect both ports into a high-impedance state. The Fairchild Quiet Series architecture addresses simultaneous-switching noise in bus-oriented designs. The exact Rochester -G suffix and lot should be checked against a controlled manufacturer record before relying on family-level numeric limits.

• Eight non-inverting bidirectional data channels.
• Three-state output disconnect for shared buses.
• Fairchild Quiet Series output switching architecture.
• TTL-compatible control inputs in the ACTQ family.
• Compact 20-lead TSSOP ordering family.

With output enable low, T/R high passes A-port data toward B; T/R low passes B-port data toward A. Output enable high places both ports in high impedance. The manufacturer-authored ACQ/ACTQ245 document describes Quiet Series GTO output control, an undershoot corrector and a split ground bus. Compare its specific electrical table with the Rochester exact-order document before specifying load current or propagation delay.

The original Fairchild ordering table maps 74ACTQ245MTC to MTC20, a 20-lead 4.4 mm-wide TSSOP under JEDEC MO-153. The catalog package field is blank. A matching 20-TSSOP registry entry was not confirmed, and no local package JPG was found; verify the exact Rochester -G package and mechanical drawing before PCB use.

Assembly checks

• Confirm 20 leads, pitch, width and pin-one orientation.
• Compare land pattern with the controlled outline.
• Check actual material finish and reel or bulk supply.

The expected 20-TSSOP JPG is missing.

The family data identifies OE as output enable, T/R as direction control, A0 to A7 as one bus and B0 to B7 as the other. OE high disables both buses; OE low enables the direction selected by T/R. Pin numbering and supply/ground placements must be checked against the exact 20-lead Rochester pin diagram before layout or substitution.

Family specifications are not a substitute for a controlled exact-order Rochester data sheet or current lot documentation.

No database-verified internal replacement is linked. A standard ACT245 may implement similar bus logic but can differ in switching noise, timing, package and compliance. Compare the full pin map, enable/direction truth table, load, input thresholds, propagation delays and physical outline before substitution.

Rochester Electronics is the catalog supplier of 74ACTQ245MTC-G. The original Fairchild 74ACQ245/74ACTQ245 document explicitly lists the MTC order code and the Quiet Series behavior; its data is family-level evidence. A manufacturer-hosted document proving the meaning and full ratings of the Rochester -G suffix was not established.

• Bidirectional eight-bit microprocessor or controller buses.
• Shared data buses requiring controlled three-state isolation.
• Legacy logic boards designed for ACTQ Quiet Series switching.

Confirm exact markings, Rochester traceability, package finish and the -G suffix before procurement. The catalog records 815 units, USD 11.49 and minimum quantity 12, without tiers. An indexed exact-code DigiKey-derived listing also showed 815 units with quantity-10 terms, while independent brokers give RFQ or different availability. A present-day authorized seller USD price ladder was not independently verified; preserve the catalog values until quote reconciliation.

Verify bus contention timing, direction changes, output-disable sequencing, load and signal integrity. The blank catalog package field, unconfirmed registry match, missing JPG, unverified exact -G ratings and unconfirmed current price terms prohibit publication.