Mechanical Dimensions & Land Pattern (TSOP-28-10.1mm)
Extracted from Datasheet & IPC-7351B NormalizedRecommended Companion BOM & Drop-In Equivalents
Passive external components per reference schematic and 1:1 pin-compatible alternatives| Designator / Replacement MPN | Value / Package | Function & PCB Layout Rule |
|---|---|---|
| N/A BOM | Per application circuit TSOP-28-10.1mm | Size power & signal trace widths for rated load current following IPC-2221 clearance rules. |
Technical Frequently Asked Questions (FAQ) — AT28HC256-90TU-T (TSOP-28-10.1mm)
Quick answers covering Pinout, IPC-7351B Land Pattern dimensions, and CAD export formatsWhat is the Pinout and operating voltage specification of AT28HC256-90TU-T (TSOP-28-10.1mm)?
Manufactured by MICROCHIP, the AT28HC256-90TU-T is housed in a TSOP-28-10.1mm package with 28 pins and a 1.27 mm lead pitch. Key pins include: 1 (A14: Multiplexed I/O & Peripheral Pin A14 (General)), 2 (A12: Multiplexed I/O & Peripheral Pin A12 (General)), 3 (A7: Multiplexed I/O & Peripheral Pin A7 (General)), 4 (A6: Multiplexed I/O & Peripheral Pin A6 (General)), 5 (A5: Multiplexed I/O & Peripheral Pin A5 (General)), 6 (A4: Multiplexed I/O & Peripheral Pin A4 (General)).
What are the IPC-7351B PCB Footprint dimensions for AT28HC256-90TU-T?
Normalized from the official datasheet mechanical drawing per IPC-7351B (Density Level B Nominal), AT28HC256-90TU-T (TSOP-28-10.1mm) has a nominal body envelope of 10.10 × 18.30 mm, pitch e = 1.27 mm, and 28 copper pads.
Where can I download KiCad (.kicad_mod, .kicad_sym), Fusion 360 (.lbr), and 3D STEP models for AT28HC256-90TU-T?
You can download the verified open-hardware (CERN-OHL-P-2.0) CAD library bundle for AT28HC256-90TU-T (MICROCHIP, TSOP-28-10.1mm) directly on this page, including KiCad 8 Footprints (.kicad_mod), Schematic Symbols (.kicad_sym), Autodesk Fusion 360 / Eagle (.lbr), and 3D STEP AP214 / WebGL GLB models.
Static Reference Appendix: Pinout Table (28 pins) & AT28HC256 Family VariantsExpand static table
| Pin # | Signal Name | Electrical Type | Functional Description & Design Notes |
|---|---|---|---|
| 1 | A14 | Digital_IO | Signal terminal A14 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A14. Supported peripheral buses: General. |
| 2 | A12 | Digital_IO | Signal terminal A12 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A12. Supported peripheral buses: General. |
| 3 | A7 | Digital_IO | Signal terminal A7 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A7. Supported peripheral buses: General. |
| 4 | A6 | Digital_IO | Signal terminal A6 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A6. Supported peripheral buses: General. |
| 5 | A5 | Digital_IO | Signal terminal A5 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A5. Supported peripheral buses: General. |
| 6 | A4 | Digital_IO | Signal terminal A4 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A4. Supported peripheral buses: General. |
| 7 | A3 | Digital_IO | Signal terminal A3 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A3. Supported peripheral buses: General. |
| 8 | A2 | Digital_IO | Signal terminal A2 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A2. Supported peripheral buses: General. |
| 9 | A1 | Digital_IO | Signal terminal A1 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A1. Supported peripheral buses: General. |
| 10 | A0 | Digital_IO | Signal terminal A0 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A0. Supported peripheral buses: General. |
| 11 | I/O0 | Digital_IO | Signal terminal I/O0 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: I/O0. Supported peripheral buses: General. |
| 12 | I/O1 | Digital_IO | Signal terminal I/O1 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: I/O1. Supported peripheral buses: General. |
| 13 | I/O2 | Digital_IO | Signal terminal I/O2 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: I/O2. Supported peripheral buses: General. |
| 14 | GND | GND | 0V electrical ground return terminal (GND) for internal core logic, I/O drivers, and analog sub-blocks. |
| 15 | I/O3 | Digital_IO | Signal terminal I/O3 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: I/O3. Supported peripheral buses: General. |
| 16 | I/O4 | Digital_IO | Signal terminal I/O4 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: I/O4. Supported peripheral buses: General. |
| 17 | I/O5 | Digital_IO | Signal terminal I/O5 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: I/O5. Supported peripheral buses: General. |
| 18 | I/O6 | Digital_IO | Signal terminal I/O6 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: I/O6. Supported peripheral buses: General. |
| 19 | I/O7 | Digital_IO | Signal terminal I/O7 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: I/O7. Supported peripheral buses: General. |
| 20 | CE# | Digital_IO | Signal terminal CE# (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: CE#. Supported peripheral buses: General. |
| 21 | A10 | Digital_IO | Signal terminal A10 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A10. Supported peripheral buses: General. |
| 22 | OE# | Digital_IO | Signal terminal OE# (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: OE#. Supported peripheral buses: General. |
| 23 | A11 | Digital_IO | Signal terminal A11 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A11. Supported peripheral buses: General. |
| 24 | A9 | Digital_IO | Signal terminal A9 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A9. Supported peripheral buses: General. |
| 25 | A8 | Digital_IO | Signal terminal A8 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A8. Supported peripheral buses: General. |
| 26 | A13 | Digital_IO | Signal terminal A13 (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: A13. Supported peripheral buses: General. |
| 27 | WE# | Digital_IO | Signal terminal WE# (I/O, 3.3V / 5.0V Standard Logic domain). Multiplexed alternate functions: WE#. Supported peripheral buses: General. |
| 28 | VCC | Power_In | Primary positive power supply input (VCC) operating in the 3.3V / 5.0V Standard Logic domain (Max rating: 5.5V). |





