DS1305N Equivalent & Substitute Parts

Part Overview

The DS1305N is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This device provides 96 bytes of non-volatile static RAM (NVSRAM), SPI interface communication, and trickle-charger capability for battery backup operation. The DS1305N is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing system support and new design implementations.

Substiute Parts

DS1305N

Analog Devices Inc./Maxim IntegratedIn Stock: 2095DS1305N Datasheet

Current PartRFQ

DS1305N+

Analog Devices Inc./Maxim IntegratedIn Stock: 1547DS1305N+ Datasheet

DirectRFQ

RX-4571SA:B3 PURE SN

EPSONIn Stock: 1338RX-4571SA:B3 PURE SN Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the DS1305N is determined by the following critical parameters:

Primary Substitution Criteria:

• Clock/Calendar functionality with matching time and date format capability
• SPI or equivalent serial interface for data communication
• Operating voltage range compatibility (minimum 2V ~ 5.5V support)
• Operating temperature range coverage (-40°C ~ 85°C minimum)
• Through-hole or surface-mount package availability
• Alarm and leap year support

Substitute Parts Identified:

1. DS1305N+ (Direct Manufacturer Upgrade): Identical electrical and functional specifications to DS1305N with active product status and ROHS3 compliance. Packaging differs (Tube vs. unspecified for original). Pin-compatible replacement.

2. RX-4571SA:B3 PURE SN (Functional Alternative): EPSON-manufactured RTC with Clock/Calendar, 3-Wire Serial interface, and matching operating temperature range. Differs in package type (14-SOIC surface mount vs. 16-DIP through hole), interface protocol (3-Wire Serial vs. SPI), and timekeeping current consumption (0.95µA ~ 1µA vs. 25.3µA ~ 81µA). Suitable for designs where package and interface migration is acceptable.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Pin-Compatible): DS1305N+ is the appropriate selection when maintaining existing PCB layouts and through-hole assembly processes. This part provides identical electrical specifications and functional features while offering active product status and ROHS3 compliance, eliminating obsolescence risk.

For New Designs or Board Redesign: RX-4571SA:B3 PURE SN is suitable when PCB redesign is feasible and surface-mount assembly capability exists. This part offers superior timekeeping current consumption (0.95µA ~ 1µA vs. 25.3µA ~ 81µA), extended lower voltage operation (1.6V minimum vs. 2V), and ROHS3 compliance. Design migration requires interface protocol conversion from SPI to 3-Wire Serial and accommodation of 12-hour time format limitation (24-hour only).

Compliance Considerations: DS1305N is RoHS non-compliant and REACH unaffected. DS1305N+ and RX-4571SA:B3 PURE SN are both ROHS3 compliant. RX-4571SA:B3 PURE SN carries REACH affected status, requiring regulatory review for applications subject to REACH requirements.

Frequently Asked Questions (FAQ)

Q: Can DS1305N+ be used as a direct replacement for DS1305N? A: Yes. DS1305N+ is pin-compatible and functionally identical, with matching SPI interface, 96B memory, alarm, leap year, NVSRAM, and trickle-charger features. No PCB or firmware modifications are required.

Q: What are the key differences between DS1305N and RX-4571SA:B3 PURE SN? A: Interface protocol differs (SPI vs. 3-Wire Serial), package type differs (16-DIP through-hole vs. 14-SOIC surface-mount), timekeeping current consumption is significantly lower in RX-4571SA:B3 (0.95µA ~ 1µA vs. 25.3µA ~ 81µA), and time format is limited to 24-hour in RX-4571SA:B3. NVSRAM and trickle-charger features are not present in RX-4571SA:B3.

Q: Is RX-4571SA:B3 PURE SN suitable for existing DS1305N designs without modification? A: No. RX-4571SA:B3 PURE SN requires PCB redesign due to different package type and pinout, firmware modification to support 3-Wire Serial protocol instead of SPI, and functional verification of 24-hour time format compatibility. This part is suitable for new designs or significant board revisions.

Q: What is the impact of RoHS compliance on part selection? A: DS1305N is RoHS non-compliant. DS1305N+ and RX-4571SA:B3 PURE SN are ROHS3 compliant. For applications subject to RoHS regulations, DS1305N+ or RX-4571SA:B3 PURE SN must be selected. Existing DS1305N inventory may be restricted from use in regulated markets.

Q: How does timekeeping current consumption affect battery life? A: RX-4571SA:B3 PURE SN consumes 0.95µA ~ 1µA during timekeeping operation, compared to 25.3µA ~ 81µA for DS1305N and DS1305N+. For battery-backed applications, RX-4571SA:B3 PURE SN provides extended battery life, typically 25 to 80 times longer depending on operating voltage and battery capacity.

Q: Are there packaging or supply chain considerations for these parts? A: DS1305N is obsolete with limited availability. DS1305N+ is active with 1469 units in stock (Tube packaging). RX-4571SA:B3 PURE SN is active with 1268 units in stock (Tape & Reel packaging). For new procurements, DS1305N+ or RX-4571SA:B3 PURE SN are recommended based on design requirements.