Quality Semiconductor QS72245-20TF

The QS722X5 family stores 18-bit words in a dual-port memory array with independent read and write pointers. Data enter under WCLK/WEN control and leave under RCLK/REN control. QS72245 provides 4,096 18-bit locations and can buffer transfers between digital subsystems with different clocks or burst patterns.

• Documented 4K x 18 family organization.
• Separate read and write port clocks.
• Full, empty and programmable almost-full/almost-empty status.
• Expansion controls for larger FIFO configurations.
• Enhanced operating mode documented by QSI.

QSI's AN-26 describes synchronized data-transfer controls, FF and EF boundary flags, programmable PAF and PAE thresholds, and shared expansion or half-full signals. WCLK and RCLK belong to separate input and output control paths. The note explains enhanced-mode selection but does not establish guaranteed -20TF timing or package dimensions.

The local catalog leaves the package blank. Other QS722X5 TF-family offers suggest a 64-pin QFP-style package, but no controlled document confirming the exact QS72245-20TF outline was located. The 64-QFP label and image path below are provisional registry candidates only; the local JPG is absent. Do not release a footprint from this draft.

Assembly checks

• Obtain the exact -20TF package and pin-one drawings.
• Do not apply the QSI PLCC family pin map to a QFP footprint without verification.
• Confirm lead pitch, body dimensions and land pattern.

The QSI family identifies D0-D17, Q0-Q17, WCLK, WEN, RCLK, REN, OE, RS, LD, FF, EF, PAF and PAE. Expansion and alternate-mode functions include FL/RT, WXI/WEN2, WXO/HF, RXI/REN2 and RXO/EF2. The original note illustrates a PLCC pinout, not a verified -20TF physical pin assignment; confirm the exact package pin map before connection.

Do not infer guaranteed cycle time, supply tolerance or operating temperature from the suffix or another manufacturer's device.

The database contains QS72245-20J, QS72245-25TF and QS72245-25J. These are same-family comparison candidates, not approved drop-in replacements. Confirm the exact package, pinout, timing grade, mode wiring and temperature range before substitution.

Quality Semiconductor's original AN-26, “QS722X5 Family, Designer-Friendly, 18-Bit-Wide Clocked FIFOs” (MAPN-00026-00, July 1995), supports the architecture, QS72245 depth and signal-function discussion. It is an application note and does not confirm the exact -20TF mechanical option, ratings or timing. Request controlled ordering and package documents.

• Temporary buffering between clocked digital blocks.
• Data-rate matching in communications and processing systems.
• Expandable FIFO queues for burst traffic.

The local catalog lists 430 units at USD 1.00, minimum quantity 11, with no tiers. Indexed DigiKey/Rochester exact-code data list 430 units, minimum order 9 and USD 32.24 at ten. Another indexed seller lists 430 units at USD 25.79/25, USD 24.50/100 and lower bulk breaks. These are seller claims, not reconciliation of the local price or stock provenance; the catalog inventory and pricing remain unchanged.

Obtain exact QS72245-20TF timing, electrical and mechanical specifications; verify pin assignment and footprint; resolve package registry/JPG; and authenticate inventory and price tiers. Keep this draft in manual review with noindex. Do not publish until all evidence and page checks pass.