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AT28HC256E-12SU

Public Made by Adom

by adom

Microchip Tech Pre-ordered MCUs, SOIC-28-300mil. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

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3D Model

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Symbol & Footprint

Schematic Symbol

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PCB Footprint

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Datasheet

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Contents

README

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AT28HC256E-12SU

Microchip Tech · Pre-ordered MCUs · SOIC-28-300mil

AT28HC256E-12SU from Microchip Tech, in a SOIC-28-300mil. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 A14 input Address input A14 for the 32,768 x 8 memory array.
2 A12 input Address input A12 for the 32,768 x 8 memory array.
3 A7 input Address input A7 for the 32,768 x 8 memory array.
4 A6 input Address input A6 for the 32,768 x 8 memory array.
5 A5 input Address input A5 for the 32,768 x 8 memory array.
6 A4 input Address input A4 for the 32,768 x 8 memory array.
7 A3 input Address input A3 for the 32,768 x 8 memory array.
8 A2 input Address input A2 for the 32,768 x 8 memory array.
9 A1 input Address input A1 for the 32,768 x 8 memory array.
10 A0 input Address input A0 for the 32,768 x 8 memory array.
11 I/O0 bidirectional Data input/output bit 0.
12 I/O1 bidirectional Data input/output bit 1.
13 I/O2 bidirectional Data input/output bit 2.
14 GND power_in Ground reference for the device.
15 I/O3 bidirectional Data input/output bit 3.
16 I/O4 bidirectional Data input/output bit 4.
17 I/O5 bidirectional Data input/output bit 5.
18 I/O6 bidirectional Data input/output bit 6.
19 I/O7 bidirectional Data input/output bit 7; DATA Polling of I/O7 indicates the end of a write cycle.
20 CE input Chip Enable input.
21 A10 input Address input A10 for the 32,768 x 8 memory array.
22 OE input Output Enable input.
23 A11 input Address input A11 for the 32,768 x 8 memory array.
24 A9 input Address input A9 for the 32,768 x 8 memory array.
25 A8 input Address input A8 for the 32,768 x 8 memory array.
26 A13 input Address input A13 for the 32,768 x 8 memory array.
27 WE input Write Enable input.
28 VCC power_in Device power supply, single 5V ±10% supply.

Key specifications

Parameter Value
Manufacturer Microchip Tech
Package SOIC-28-300mil
Category Embedded Processors & Controllers
Pins 28

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter Symbol Min Typ Max Unit Conditions Page
VCC Power Supply tolerance VCC -10 10 % VCC Power Supply 5V ± 10% 7
Operating Temperature (Case) Industrial -40 85 °C Industrial, AT28HC256-12 7
VCC Power Supply VCC 5 V 5V ± 10% (see tolerance row) 7
Temperature under bias -55 125 °C 7
Storage temperature -65 150 °C 7
All input voltages (including NC pins) with respect to ground -0.6 6.25 V 7
All output voltages with respect to ground -0.6 V Upper limit printed as VCC + 0.6V 7
Voltage on OE and A9 with respect to ground -0.6 13.5 V 7
Input Load Current ILI 10 μA VIN = 0V to VCC + 1V 7
Output Leakage Current ILO 10 μA VI/O = 0V to VCC 7
VCC Standby Current TTL ISB1 3 mA CE = 2.0V to VCC, for AT28HC256-90, -12 7
VCC Standby Current CMOS ISB2 300 μA CE = VCC - 0.3V to VCC, for AT28HC256-90, -12 7
VCC Active Current ICC 80 mA f = 5 MHz; IOUT = 0 mA 7
Input Low Voltage VIL 0.8 V 7
Input High Voltage VIH 2 V 7
Output Low Voltage VOL 0.45 V IOL = 6.0 mA 7
Output High Voltage VOH 2.4 V IOH = -4 mA 7
Input Capacitance CIN 4 6 pF VIN = 0V 8
Output Capacitance COUT 8 12 pF VOUT = 0V 8
Address to Output Delay tACC 120 ns 11
CE to Output Delay tCE 120 ns 11
OE to Output Delay tOE 0 50 ns 11
CE or OE to Output Float tDF 0 50 ns 11
Output Hold from OE, CE or Address, whichever occurred first tOH 0 ns 11
Address, OE Setup Time tAS, tOES 0 ns 13
Address Hold Time tAH 50 ns 13
Chip Select Setup Time tCS 0 ns 13
Chip Select Hold Time tCH 0 ns 13
Write Pulse Width (WE or CE) tWP 100 ns 13
Data Setup Time tDS 50 ns 13
Data, OE Hold Time tDH, tOEH 0 ns 13
Write Cycle Time (option available) AT28HC256 tWC 10 ms Base AT28HC256 (blank option) 14
Address Setup Time tAS 0 ns Page mode write 14
Address Hold Time (page mode) tAH 50 ns Page mode write 14
Data Setup Time (page mode) tDS 50 ns Page mode write 14
Data Hold Time (page mode) tDH 0 ns Page mode write 14
Write Pulse Width (page mode) tWP 100 ns Page mode write 14
Byte Load Cycle Time tBLC 150 µs 14
Write Pulse Width High tWPH 50 ns 14
Data Polling Data Hold Time tDH 0 ns Data polling, characterized not 100% tested 18
Data Polling OE Hold Time tOEH 0 ns Data polling, characterized not 100% tested 18
Write Recovery Time (data polling) tWR 0 ns Data polling, characterized not 100% tested 18
Data Hold Time (toggle bit) tDH 10 ns Toggle bit, characterized not 100% tested 19
OE Hold Time (toggle bit) tOEH 10 ns Toggle bit, characterized not 100% tested 19
OE High Pulse tOEHP 150 ns Toggle bit, see AC Read Characteristics 19
Write Recovery Time (toggle bit) tWR 0 ns Toggle bit, characterized not 100% tested 19

Materials and finish

As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).

Part Material Colour / plating Datasheet says Page
contacts tin U = -40°C to +85°C Industrial Temperature Grade, 100% Matte Sn Terminal Finish AT28 HC 256 ( )- 90 JU-T 30

CAD (KiCad official)

  • Symbol: AT28HC256E-12SU
  • Footprint: Package_SO:SOIC-28W_7.5x17.9mm_P1.27mm
  • 3D model: SOIC-28-300mil (KiCad packages3D, STEP)
  • 3D model files: at28hc256e-12su-etched.step / at28hc256e-12su-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); at28hc256e-12su.step / at28hc256e-12su.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Microchip Tech datasheet (34 pp, sha256 9fbfb62b758b1eb8, retrieved 2026-10-28, tier: manufacturer)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF