Quality Semiconductor QS72245-25TF

The QS72245 provides temporary storage and rate matching between digital data paths using separate write and read clocks. The family was designed for high-performance systems where an 18-bit word width can replace paired 9-bit FIFOs. This page distinguishes verified QS722X5 family behavior from unconfirmed details of the QS72245-25TF order code.

• 4,096-word by 18-bit QS72245 family organization.
• Independent clocked write and read ports.
• Configurable status flags for FIFO management.
• Programmable offset and control registers.
• Enhanced and IDT-compatible operating modes described by the manufacturer.

Write-side transfers are synchronized to WCLK and read-side transfers to RCLK, with corresponding enable controls. The QS722X5 note describes full, empty and middle status flags, programmable offset registers, and an LD-controlled sequence for writing or reading configuration registers. Enhanced mode adds control-register access; IDT-compatible mode uses a reduced register sequence. Confirm exact flag timing and reset behavior in the device data sheet.

The local catalog package field is blank. The family application note illustrates a 68-pin PLCC pinout, while compatible IDT devices use a TF code for a 64-pin slim thin quad flatpack. Neither source proves the exact QS72245-25TF outline. A 64-TQFP is only a candidate for investigation, not a verified footprint; obtain the Quality Semiconductor ordering table and mechanical drawing before layout.

Assembly checks

• Confirm whether TF denotes a 64-lead flatpack for this vendor.
• Verify body size, pitch and pin-one orientation.
• Compare the pin map with the controlled exact-code drawing.

The local 64-TQFP JPG is missing, and the package registry match is unconfirmed.

Family signals include 18-bit data input and output buses, WCLK and RCLK, write/read enables, status flags and LD for register access. The manufacturer note's illustrated pin numbers are for its 68-pin PLCC example, not a verified -25TF pin map. Never transfer those positions to a candidate flatpack without the exact drawing.

Family-level characteristics are not a substitute for exact -25TF switching and package specifications.

The database contains related order codes QS72245-20TF, QS72245-35TF and QS72245-25J. These are comparison candidates, not approved drop-in substitutes: speed grade, package, pinout, status timing, temperature rating and sourcing must all be checked.

A Quality Semiconductor-authored QS722X5 family application note identifies the 18-bit synchronous FIFO architecture and QS72245 depth. It discusses pin-compatible and functional compatibility with a historical IDT family at the family level. The exact QS72245-25TF manufacturer ordering table and package outline were not established.

• Clock-domain buffering in legacy high-performance digital systems.
• Temporary 18-bit data storage between processing stages.
• Data-rate matching between independently clocked ports.

Confirm markings, suffix, lot traceability, moisture handling and physical package. The local catalog lists 800 units at USD 1.00, minimum quantity 12 and no tiers. An indexed DigiKey/Rochester listing shows 800 units at USD 30.70 for ten, and another reseller shows 880 units at USD 27.016 for ten. The large price discrepancy is unresolved; do not present the catalog figure as a verified current market quote or update pricing without authorized reconciliation.

Review asynchronous clock crossing, full/empty flag synchronization, reset and LD control timing, and physical pinout. Missing package evidence and JPG plus the substantial catalog-versus-distributor price conflict prohibit publication.