AT25256B-CUL-T Equivalent & Substitute Parts

Part Overview

The AT25256B-CUL-T is a 256Kbit Serial Peripheral Interface (SPI) EEPROM memory IC manufactured by Microchip Technology. This non-volatile memory device operates across a wide voltage range (1.8V to 5.5V) and is housed in an 8-dBGA package measuring 2.35x3.73mm. The component is currently in active production status with 3,100 units available in new original inventory. Substitute parts are identified when equivalent electrical specifications and mechanical compatibility requirements are met within the same memory category.

Substiute Parts

AT25256B-CUL-T

Microchip TechnologyIn Stock: 3167AT25256B-CUL-T Datasheet

Current PartRFQ

M95256-DFCS6TP/K

STMicroelectronicsIn Stock: 17797M95256-DFCS6TP/K Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the AT25256B-CUL-T is determined by matching the following critical parameters:

• Memory capacity: 256Kbit
• Memory organization: 32K x 8 configuration
• Interface protocol: SPI
• Clock frequency: 20 MHz maximum
• Write cycle time: 5ms
• Supply voltage compatibility: minimum 1.8V operation
• Operating temperature range: -40°C to 85°C
• Surface mount technology
• RoHS3 compliance

The M95256-DFCS6TP/K from STMicroelectronics meets all substitution criteria. While package geometry differs (8-WLCSP versus 8-dBGA), both are surface-mount BGA variants with equivalent electrical performance and pinout compatibility for SPI EEPROM applications.

Parameter Comparison

Engineering Selection Recommendations

Both the AT25256B-CUL-T and M95256-DFCS6TP/K are active production components with ROHS3 compliance and REACH unaffected status. Selection between these parts should be based on:

• PCB layout constraints and available footprint space for the respective BGA package geometries
• Moisture sensitivity requirements for storage and handling; the M95256-DFCS6TP/K offers superior moisture tolerance (MSL 1 versus MSL 3)
• Supply voltage floor requirement; the AT25256B-CUL-T supports operation down to 1.8V while the M95256-DFCS6TP/K operates from 1.7V minimum
• Inventory availability and lead time considerations

Frequently Asked Questions (FAQ)

Q: Can the M95256-DFCS6TP/K directly replace the AT25256B-CUL-T on existing PCBs?

A: Direct PCB replacement is not possible due to different package types (8-WLCSP versus 8-dBGA). However, both devices are electrically equivalent for SPI EEPROM applications and can be used interchangeably in new designs with appropriate footprint accommodation.

Q: Are there pinout differences between these two parts?

A: Both parts maintain SPI interface pinout compatibility (MOSI, MISO, CLK, CS). Physical pin locations differ due to package geometry variations, requiring layout redesign for substitution.

Q: What is the significance of the MSL rating difference?

A: MSL 3 (AT25256B-CUL-T) allows 168 hours of exposure to 85°C/85% relative humidity before reflow. MSL 1 (M95256-DFCS6TP/K) has unlimited shelf life under controlled conditions. The M95256-DFCS6TP/K is more tolerant of extended storage without baking requirements.

Q: Do both parts support the same SPI clock frequency?

A: Yes, both devices support 20 MHz maximum clock frequency and are fully compatible for SPI protocol implementation.

Q: Are there voltage supply considerations for substitution?

A: The AT25256B-CUL-T operates from 1.8V minimum, while the M95256-DFCS6TP/K operates from 1.7V minimum. Both support the full 5.5V maximum. Designs operating below 1.7V require the AT25256B-CUL-T.