DS1557P-70IND Real Time Clock (RTC) IC Equivalent & Substitute Parts

Part Overview

The DS1557P-70IND is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This device features 512KB parallel memory interface with alarm, leap year compensation, NVSRAM, watchdog timer, and Y2K support. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations. Substitute parts are selected based on matching electrical specifications, interface compatibility, and functional feature parity.

Substiute Parts

DS1557P-70IND

Analog Devices Inc./Maxim IntegratedIn Stock: 1100DS1557P-70IND Datasheet

Current PartRFQ

DS1557P-70IND+

Analog Devices Inc./Maxim IntegratedIn Stock: 980DS1557P-70IND+ Datasheet

DirectRFQ

BQ4802LYPW

Texas InstrumentsIn Stock: 9564BQ4802LYPW Datasheet

MFR RecommendedRFQ

DP8573AV/NOPB

Texas InstrumentsIn Stock: 4247DP8573AV/NOPB Datasheet

MFR RecommendedRFQ

M48T58Y-70PC1

STMicroelectronicsIn Stock: 1732M48T58Y-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DS1557P-70IND are identified based on the following substitution criteria:

Primary Substitution Criteria:

• Parallel interface architecture
• Clock/Calendar functionality with date and time tracking
• Alarm and watchdog timer features
• Operating voltage compatibility within 4.5V ~ 5.5V range
• 24-hour time format support
• YY-MM-DD-dd date format support
• Surface mount or through-hole mounting capability
• RoHS3 compliance status (preferred for modern applications)

Substitution Groups:

Group 1: Direct Equivalent (Same Manufacturer, Active Status)

• DS1557P-70IND+ (Analog Devices Inc./Maxim Integrated) - Identical electrical and functional specifications with active product status and RoHS3 compliance

Group 2: Functional Equivalents (Parallel Interface, Voltage Compatible)

• DP8573AV/NOPB (Texas Instruments) - Parallel interface, 4.5V ~ 5.5V supply, alarm and leap year features, 28-PLCC package
• M48T58Y-70PC1 (STMicroelectronics) - Parallel interface, 4.5V ~ 5.5V supply, leap year feature, 28-DIP through-hole package

Group 3: Lower Voltage Alternative (Reduced Supply Range)

• BQ4802LYPW (Texas Instruments) - Parallel interface, reduced voltage range (2.7V ~ 3.6V), alarm and watchdog timer features, 28-TSSOP package

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Recommended Primary Choice): DS1557P-70IND+ is the optimal substitute. It maintains identical electrical specifications, functional features, and package form factor as the obsolete DS1557P-70IND while offering active product status and RoHS3 compliance. This part requires no design modifications and provides the highest compatibility assurance.

For New Designs or When Package Flexibility Exists: DP8573AV/NOPB (Texas Instruments) provides functional equivalence with parallel interface, matching voltage supply range (4.5V ~ 5.5V), and essential clock/calendar features. The 28-PLCC package differs from the original 34-PowerCap™ Module, requiring PCB layout adaptation. This part offers superior timekeeping current efficiency (1µA @ 5V) and RoHS3 compliance.

For Through-Hole Mounting Applications: M48T58Y-70PC1 (STMicroelectronics) is suitable when through-hole mounting is required. It maintains 4.5V ~ 5.5V supply compatibility and 24-hour time format support. Operating temperature range is limited to 0°C ~ 70°C, which may restrict use in extended temperature applications. RoHS3 compliance is confirmed.

For Low-Voltage System Integration: BQ4802LYPW (Texas Instruments) is applicable only when system voltage supply is reduced to 2.7V ~ 3.6V range. This part is not suitable as a direct substitute for 5V systems. It provides enhanced watchdog timer and daylight savings features with RoHS3 compliance and unlimited MSL rating.

Compliance Considerations: All substitute parts except the main DS1557P-70IND carry RoHS3 compliance certification. For applications requiring RoHS compliance, DS1557P-70IND+ is the mandatory choice among direct equivalents. All substitute parts maintain EAR99 ECCN classification and REACH Unaffected status.

Frequently Asked Questions (FAQ)

Q: Can DS1557P-70IND+ be used as a direct replacement for DS1557P-70IND? A: Yes. DS1557P-70IND+ is electrically and functionally identical to the obsolete DS1557P-70IND. It maintains the same 34-PowerCap™ Module package, 4.5V ~ 5.5V supply voltage, 512KB memory, parallel interface, and all features including alarm, leap year, NVSRAM, watchdog timer, and Y2K support. The primary difference is active product status and RoHS3 compliance.

Q: What are the key differences between DP8573AV/NOPB and the original DS1557P-70IND? A: DP8573AV/NOPB differs in package form factor (28-PLCC versus 34-PowerCap™ Module), pin count, and memory size specification. Both maintain 4.5V ~ 5.5V supply compatibility and parallel interface architecture. DP8573AV/NOPB offers significantly lower timekeeping current (1µA @ 5V versus 6mA @ 5V) and extended battery voltage range (2.2V ~ 5.1V). PCB layout redesign is required for package migration.

Q: Is M48T58Y-70PC1 suitable for high-temperature applications? A: No. M48T58Y-70PC1 operates within 0°C ~ 70°C temperature range, which is narrower than the original DS1557P-70IND specification of -40°C ~ 85°C. This part is not suitable for applications requiring extended temperature operation below 0°C or above 70°C.

Q: Can BQ4802LYPW replace DS1557P-70IND in a 5V system? A: No. BQ4802LYPW operates at 2.7V ~ 3.6V supply voltage and is not compatible with 5V systems. This part is applicable only for low-voltage system designs. For 5V applications, use DS1557P-70IND+, DP8573AV/NOPB, or M48T58Y-70PC1.

Q: What is the impact of package differences on system integration? A: Package differences require PCB layout modifications. DS1557P-70IND+ maintains the original 34-PowerCap™ Module package, requiring no layout changes. DP8573AV/NOPB uses 28-PLCC package, M48T58Y-70PC1 uses 28-DIP through-hole package, and BQ4802LYPW uses 28-TSSOP surface mount package. Each package change necessitates footprint redesign and potential signal routing adjustments.

Q: Are all substitute parts RoHS3 compliant? A: All substitute parts listed (DS1557P-70IND+, DP8573AV/NOPB, M48T58Y-70PC1, BQ4802LYPW) carry RoHS3 compliance certification. The original DS1557P-70IND is RoHS non-compliant. For applications requiring RoHS compliance, substitute parts are mandatory.

Q: Which substitute part offers the best timekeeping current efficiency? A: DP8573AV/NOPB provides the lowest timekeeping current at 1µA @ 5V, compared to 6mA @ 5V for DS1557P-70IND and 3mA @ 4.5V ~ 5.5V for M48T58Y-70PC1. This efficiency advantage is significant for battery-backed timekeeping applications.

Q: What is the MSL (Moisture Sensitivity Level) consideration for these parts? A: DS1557P-70IND and DS1557P-70IND+ carry MSL 3 rating (168 hours), requiring controlled storage and handling. DP8573AV/NOPB carries MSL 2A (4 weeks). M48T58Y-70PC1 and BQ4802LYPW carry MSL 1 (unlimited), offering the most relaxed moisture handling requirements.