DS1305EN Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1305EN is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This component provides 96 bytes of NVSRAM, SPI interface, and features including alarm capability, leap year compensation, and trickle-charger functionality. The DS1305EN is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and production continuity.

Substiute Parts

DS1305EN

Analog Devices Inc./Maxim IntegratedIn Stock: 6614DS1305EN Datasheet

Current PartRFQ

DS1305EN+

Analog Devices Inc./Maxim IntegratedIn Stock: 3070DS1305EN+ Datasheet

DirectRFQ

S-35192A-I8T1U

ABLIC Inc.In Stock: 776S-35192A-I8T1U Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the DS1305EN is determined by the following critical parameters:

Primary Compatibility Criteria:

• Interface type (SPI vs. 3-Wire Serial)
• Package type and form factor (20-TSSOP vs. alternative packages)
• Supply voltage range compatibility (2V ~ 5.5V minimum)
• Operating temperature range (-40°C ~ 85°C minimum)
• Time and date format support (HH:MM:SS 12/24 hr, YY-MM-DD-dd)
• Core features (Alarm, Leap Year functionality)

Identified Substitute Categories:

1. Direct Pin-Compatible Substitute (Same Package, Same Interface): DS1305EN+ - Active product status, identical electrical and mechanical specifications, ROHS3 compliant packaging variant.

2. Functional Equivalent (Different Package, Different Interface): S-35192A-I8T1U - Functionally equivalent Clock/Calendar RTC with 3-Wire Serial interface in 8-SMD package. Meets core timing and temperature requirements but requires interface protocol adaptation.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (No Design Changes Required):

DS1305EN+ is the appropriate selection when maintaining existing PCB layouts and firmware. This part is pin-compatible, electrically identical, and maintains the same SPI interface protocol. The transition from obsolete to active product status is supported by ROHS3 compliance, making DS1305EN+ suitable for new production runs and long-term supply chain stability.

For Design Flexibility (Interface Protocol Change Required):

S-35192A-I8T1U provides functional Clock/Calendar capability with improved power efficiency (8µA ~ 14µA timekeeping current versus 25.3µA ~ 81µA). This part requires firmware modification to support 3-Wire Serial interface instead of SPI, and PCB redesign for the 8-SMD package. The extended supply voltage range (1.3V ~ 5.5V) offers additional design flexibility for low-power applications. ROHS3 compliance and active product status ensure long-term availability.

Compliance Considerations:

Both substitute parts carry ROHS3 compliance and REACH Unaffected status. Selection between DS1305EN+ and S-35192A-I8T1U should prioritize design continuity (DS1305EN+) unless power consumption reduction or extended voltage range requirements justify interface and package migration (S-35192A-I8T1U).

Frequently Asked Questions (FAQ)

Q: Can DS1305EN+ be used as a direct drop-in replacement for DS1305EN?

A: Yes. DS1305EN+ is electrically and mechanically identical to DS1305EN, with identical pin configuration, SPI interface, supply voltage range (2V ~ 5.5V), operating temperature range (-40°C ~ 85°C), and feature set (Alarm, Leap Year, NVSRAM, Trickle-Charger). No firmware or PCB modifications are required. The primary difference is product status (Active vs. Obsolete) and RoHS compliance (ROHS3 vs. non-compliant).

Q: What are the key differences between DS1305EN+ and S-35192A-I8T1U?

A: DS1305EN+ maintains identical specifications to DS1305EN with SPI interface in 20-TSSOP package. S-35192A-I8T1U is a functional equivalent with 3-Wire Serial interface in 8-SMD package. S-35192A-I8T1U offers lower timekeeping current (8µA ~ 14µA vs. 25.3µA ~ 81µA) and extended supply voltage range (1.3V ~ 5.5V vs. 2V ~ 5.5V). Both support identical time/date formats and operating temperature range. S-35192A-I8T1U does not specify NVSRAM size or trickle-charger feature.

Q: Does S-35192A-I8T1U require firmware changes?

A: Yes. S-35192A-I8T1U uses 3-Wire Serial interface protocol, whereas DS1305EN uses SPI. Firmware modifications are necessary to support the different communication protocol. Additionally, PCB layout changes are required due to different package type (8-SMD vs. 20-TSSOP).

Q: Are both substitute parts RoHS compliant?

A: Yes. Both DS1305EN+ and S-35192A-I8T1U carry ROHS3 Compliant status. The original DS1305EN is RoHS non-compliant. This compliance improvement supports modern manufacturing and regulatory requirements.

Q: What is the operating temperature range for all three parts?

A: All three parts (DS1305EN, DS1305EN+, and S-35192A-I8T1U) operate across -40°C to 85°C, ensuring compatibility for industrial and commercial temperature environments.

Q: Which substitute should be selected for new designs?

A: For designs requiring SPI interface and 20-TSSOP package, DS1305EN+ is the appropriate selection. For new designs where interface flexibility and power efficiency are priorities, S-35192A-I8T1U offers advantages in timekeeping current consumption and extended voltage range, provided firmware and PCB redesign are feasible.