AB1813-T3 Equivalent & Substitute Parts

Part Overview

The AB1813-T3 is a Real Time Clock (RTC) IC Clock/Calendar with 64B SPI interface manufactured by Abracon LLC in a 16-VFQFN Exposed Pad package. This component provides timekeeping functionality with alarm capability, leap year support, SRAM, and trickle-charger features. The part is currently classified as Obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. Substitute parts must maintain functional compatibility across core timekeeping parameters, interface protocol, and operating conditions.

Substiute Parts

AB1813-T3

Abracon LLCIn Stock: 1055AB1813-T3 Datasheet

Current PartRFQ

AB1815-T3

Abracon LLCIn Stock: 52178AB1815-T3 Datasheet

DirectRFQ

DS1390U-33+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 12286DS1390U-33+T&R Datasheet

MFR RecommendedRFQ

MCP79512T-I/MS

Microchip TechnologyIn Stock: 1123MCP79512T-I/MS Datasheet

MFR RecommendedRFQ

MCP795W10T-I/SL

Microchip TechnologyIn Stock: 1070MCP795W10T-I/SL Datasheet

MFR RecommendedRFQ

MCP795W11T-I/ST

Microchip TechnologyIn Stock: 1114MCP795W11T-I/ST Datasheet

MFR RecommendedRFQ

PCF2123TS/1,118

NXP USA Inc.In Stock: 2045PCF2123TS/1,118 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the AB1813-T3 are selected based on the following critical parameters that determine functional compatibility:

Primary Compatibility Criteria:

• Interface Protocol: SPI (mandatory match)
• Time Format: HH:MM:SS:hh (12/24 hour capability)
• Date Format: YY-MM-DD-dd (mandatory match)
• Operating Temperature Range: -40°C ~ 85°C (mandatory match)
• RoHS Compliance: ROHS3 Compliant (mandatory match)
• Moisture Sensitivity Level: 1 (Unlimited) (mandatory match)

Secondary Compatibility Criteria:

• Memory Size: 64B minimum
• Supply Voltage Overlap: 1.7V ~ 3.6V range
• Battery Supply Voltage Overlap: 1.5V ~ 3.6V range
• Timekeeping Current: Low power operation capability
• Mounting Type: Surface Mount

Substitutes are grouped into two categories based on package compatibility:

Group 1 - Same Package (16-VFQFN): Direct pin-compatible replacement with identical footprint.

Group 2 - Alternative Packages (10-MSOP, 14-SOIC, 14-TSSOP): Functional equivalents requiring PCB layout modification and potential firmware adjustment for pin reassignment.

Parameter Comparison

Engineering Selection Recommendations

AB1815-T3 (Abracon LLC): This is the primary recommended substitute. It maintains identical package geometry (16-VFQFN Exposed Pad), supply voltage range (1.7V ~ 3.6V), battery voltage range (1.5V ~ 3.6V), timekeeping current specifications (0.17µA ~ 0.22µA @ 1.8V ~ 3V), and operating temperature range (-40°C ~ 85°C). The AB1815-T3 is Active status with ROHS3 compliance and MSL 1 rating. The primary difference is increased memory (256B vs. 64B) and addition of watchdog timer functionality, which provides enhanced capability without compromising compatibility. This part requires no PCB layout changes.

DS1390U-33+T&R (Analog Devices Inc./Maxim Integrated): This substitute requires package change to 10-TFSOP/10-MSOP and PCB layout modification. Supply voltage range (2.97V ~ 5.5V) extends higher than the original part. Timekeeping current is significantly higher (175µA @ 2.97V ~ 5.5V), making it unsuitable for ultra-low-power applications. Active status with ROHS3 compliance and MSL 1 rating. Selection requires design review for power budget impact.

MCP79512T-I/MS (Microchip Technology): This substitute requires package change to 10-MSOP and PCB layout modification. Supply voltage range (1.8V ~ 3.6V) is compatible with the original part's operating range. Timekeeping current (1µA @ 1.8V ~ 3.6V) is higher than the original specification. Active status with ROHS3 compliance and MSL 1 rating. Includes EEPROM and Unique ID features.

MCP795W10T-I/SL (Microchip Technology): This substitute requires package change to 14-SOIC and PCB layout modification. Supply voltage range (1.8V ~ 3.6V) is compatible. Timekeeping current (1µA @ 1.8V ~ 5.5V) is higher than the original specification. Active status with ROHS3 compliance and MSL 1 rating. Includes watchdog timer and EEPROM features.

MCP795W11T-I/ST (Microchip Technology): This substitute requires package change to 14-TSSOP and PCB layout modification. Supply voltage range (1.8V ~ 3.6V) is compatible. Timekeeping current (1µA @ 1.8V ~ 5.5V) is higher than the original specification. Active status with ROHS3 compliance and MSL 1 rating. Includes watchdog timer, EEPROM, and Unique ID features.

PCF2123TS/1,118 (NXP USA Inc.): This substitute requires package change to 14-TSSOP and PCB layout modification. Supply voltage range (1.6V ~ 5.5V) extends beyond the original part's range. Timekeeping current (0.33µA ~ 0.38µA @ 2V ~ 5V) is higher than the original specification. Active status with ROHS3 compliance and MSL 1 rating. Battery supply voltage specification is not provided.

Frequently Asked Questions (FAQ)

Q: Can AB1815-T3 be used as a direct replacement for AB1813-T3?

A: Yes. The AB1815-T3 maintains identical package (16-VFQFN Exposed Pad), supply voltage range (1.7V ~ 3.6V), battery voltage range (1.5V ~ 3.6V), timekeeping current specifications (0.17µA ~ 0.22µA @ 1.8V ~ 3V), and operating temperature range (-40°C ~ 85°C). No PCB layout changes are required. The increased memory (256B vs. 64B) and watchdog timer are additional features that do not affect compatibility.

Q: What are the key differences between the 16-VFQFN package substitutes and the alternative package options?

A: The AB1815-T3 maintains the same 16-VFQFN Exposed Pad package as the original AB1813-T3, requiring no PCB layout modifications. The DS1390U-33+T&R, MCP79512T-I/MS, MCP795W10T-I/SL, MCP795W11T-I/ST, and PCF2123TS/1,118 use different packages (10-MSOP, 14-SOIC, or 14-TSSOP) and require PCB redesign, schematic updates, and potential firmware modifications for pin reassignment.

Q: Which substitute has the lowest timekeeping current consumption?

A: The AB1815-T3 and AB1813-T3 both specify 0.17µA ~ 0.22µA @ 1.8V ~ 3V, the lowest among all listed parts. The PCF2123TS/1,118 specifies 0.33µA ~ 0.38µA @ 2V ~ 5V. The Microchip MCP795 series and DS1390U-33+T&R specify higher timekeeping currents (1µA and 175µA respectively), making them less suitable for ultra-low-power battery-backed applications.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts (AB1815-T3, DS1390U-33+T&R, MCP79512T-I/MS, MCP795W10T-I/SL, MCP795W11T-I/ST, and PCF2123TS/1,118) are ROHS3 Compliant with Moisture Sensitivity Level 1 (Unlimited), matching the original AB1813-T3 specifications.

Q: What is the impact of using DS1390U-33+T&R in a low-power design?

A: The DS1390U-33+T&R specifies timekeeping current of 175µA @ 2.97V ~ 5.5V, which is significantly higher than the original AB1813-T3 specification of 0.17µA ~ 0.22µA @ 1.8V ~ 3V. This 800x increase in current consumption makes it unsuitable for battery-backed timekeeping applications requiring extended runtime. Design review is required to assess power budget impact.

Q: Do all substitutes support the same time and date formats?

A: All substitutes support the required YY-MM-DD-dd date format. For time format, all support HH:MM:SS:hh with 12/24 hour capability except PCF2123TS/1,118, which specifies HH:MM:SS (12/24 hr) without the subsecond field notation. Firmware verification is required to confirm subsecond resolution support.

Q: Which substitutes are currently in Active product status?

A: All substitute parts are Active status: AB1815-T3, DS1390U-33+T&R, MCP79512T-I/MS, MCP795W10T-I/SL, MCP795W11T-I/ST, and PCF2123TS/1,118. The original AB1813-T3 is Obsolete, making substitution necessary for new designs and production continuity.

Q: What supply voltage considerations apply when selecting a substitute?

A: The original AB1813-T3 operates at 1.7V ~ 3.6V supply voltage. All substitutes support this range or extend it: AB1815-T3 (1.7V ~ 3.6V), MCP79512T-I/MS (1.8V ~ 3.6V), MCP795W10T-I/SL (1.8V ~ 3.6V), MCP795W11T-I/ST (1.8V ~ 3.6V), PCF2123TS/1,118 (1.6V ~ 5.5V), and DS1390U-33+T&R (2.97V ~ 5.5V). Verify that the selected substitute's supply voltage range is compatible with your system's power distribution design.