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Analog Devices Inc./Maxim Integrated DS1554WP-120IND+
- Part No.:
- DS1554WP-120IND+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Real Time Clocks
- Package:
- 34-PowerCap™ Module
- Datasheet:
-
DS1554WP-120IND+.pdf
- Description:
- IC RTC CLK/CALENDAR PAR 34PCM
- Quantity:
- Payment:
- Shipping:
Inventory:259
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Product details
Overview
DS1554WP-120IND+ from Maxim Integrated is a 3.3V, industrial-grade (–40°C to +85°C), 256kbit nonvolatile timekeeping RAM integrating RTC, NV SRAM, crystal, lithium battery, power-fail control, and watchdog timer. It provides BCD-coded century/year/month/date/hour/minute/second with automatic leap-year compensation through year 2100 and delivers 10-year data retention in battery-backup mode.
For engineers reviewing the DS1554WP-120IND+ datasheet, DS1554WP-120IND+ pinout, DS1554WP-120IND+ application, or DS1554WP-120IND+ equivalent, this page details its PowerCap module architecture, 34-pin interface, Y2K-compliant register map, battery voltage monitoring, and dual-mode interrupt/reset signaling for embedded system timekeeping and fail-safe operation.
Technical Context
The DS1554WP-120IND+ implements a double-buffered RTC register set (7FF0h–7FFFh) with independent internal/external update paths, enabling atomic clock reads without data corruption. Its oscillator uses an integrated 32.768kHz crystal and supports programmable start/stop via the OSC bit (B7 of 7FF9h).
Power management includes three distinct operating states: full VCC access (VCC > VPF), CMOS standby (VSO < VCC < VPF), and battery-backed data retention (VCC < VSO). The device features open-drain IRQ/FT and RST outputs, with IRQ/FT configurable for alarm, frequency test (512Hz toggle), or watchdog signaling, and RST providing precision power-on reset with 40–200ms assertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256kbit (32k × 8) nonvolatile static RAM with RTC registers mapped into top 16 addresses (7FF0h–7FFFh) |
| RTC Accuracy | ±1.53 minutes/month (35 ppm) at 25°C when used with DS9034PCX PowerCap |
| Supply Voltage | 3.3V ±10% - supports stable operation across industrial temperature range (–40°C to +85°C) |
| Power-Fail Threshold | VPF = 2.75V to 2.97V - disables write access before VCC drops below safe logic level |
| Battery Switchover | VSO = VBAT or VPF - seamless transition to internal lithium backup with no data loss or clock stoppage |
| Retention Time | 10 years minimum at +25°C with oscillator running - guaranteed by factory-disconnected lithium source |
| Interface Speed | tRC = 70–120ns - compatible with high-speed microcontroller bus timing at 3.3V |
Pinout & Package
DS1554WP-120IND+ uses a 34-pin PowerCap module package (PC2+2), where the DS1554 die is mounted on a carrier board and mates with a separate DS9034PCX PowerCap containing the crystal and lithium battery. This design enables surface-mount reflow of the base board prior to PowerCap insertion, preventing thermal damage to sensitive components.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus for accessing 32k × 8 memory space and RTC registers |
| DQ0–DQ7 | Data I/O | Bi-directional 8-bit data bus supporting byte-wide read/write operations |
| IRQ/FT | Open-Drain Interrupt/Frequency Test Output | Configurable output for RTC alarm, watchdog timeout, or 512Hz oscillator test signal |
| RST | Open-Drain Power-On Reset Output | Asserts low for 40–200ms after VCC stabilizes - provides reliable CPU reset during power recovery |
| CE, OE, WE | Chip/Output/Write Enable Controls | Standard SRAM control signals enabling compatibility with microcontroller memory interfaces |
| VBAT | Lithium Battery Connection | Direct connection point to internal backup battery - monitored via BLF flag in Flags Register (7FF0h) |
| X1, X2 | Crystal Terminals | Connect to external 32.768kHz crystal when used in non-PowerCap variants; unused in DS1554WP-120IND+ |
| N.C. | No Connection | Pins 3, 4, 17, 33, 34 - electrically isolated; no internal circuitry attached |
Key Features
| Feature | Design Value |
|---|---|
| Y2K-Compliant Century Register | Full 21st-century support via dedicated BCD-encoded century byte (B4–B7 of 7FF8h), valid through year 2100 |
| Programmable Watchdog Timer | Configurable timeout from 1/16s to 124s using 5-bit multiplier (BMB4–BMB0) and 2-bit resolution (RB1–RB0) in 7FF7h |
| Alarm Flexibility | Four mask bits (AM1–AM4) enable repeat intervals from once-per-second to once-per-month - supports wake-from-backup functionality |
| Battery Voltage Monitoring | BLF flag (bit B4 of 7FF0h) indicates exhausted lithium source - alerts firmware before RTC/SRAM integrity is compromised |
| Power-Fail Write Protection | Automatic CE deassertion at VCC ≤ VPF ensures no partial writes occur during brownout - critical for data consistency |
Applications
| Industrial PLC Control | Medical Device Logging |
|---|---|
Use Scenario: Real-time timestamping of sensor readings and fault events in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Primary timekeeping and event logging engine - maintains accurate UTC-aligned timestamps independent of host CPU uptime or power cycles. Use Value: Guarantees deterministic time stamps for regulatory compliance and root-cause analysis, even during extended mains outages supported by onboard lithium backup. |
Use Scenario: Long-term patient vital sign storage in portable diagnostic equipment requiring FDA-compliant audit trails and battery-backed operation. IC Role / Device Role / Timing Role: Nonvolatile timekeeper and secure data buffer - synchronizes ECG/SpO₂ samples with precise BCD-formatted timestamps traceable to calendar date. Use Value: Enables 10-year continuous logging without external battery replacement, meeting IEC 62304 software lifecycle requirements for Class II medical devices. |
| Smart Energy Metering | Avionics Health Monitoring |
Use Scenario: Tamper-resistant energy consumption recording in utility smart meters operating across wide ambient temperatures and intermittent grid power. IC Role / Device Role / Timing Role: Secure time-of-use (TOU) clock and tamper-evident log buffer - stores billing intervals and meter events with hardware-enforced write protection. Use Value: Prevents clock manipulation via VCC-based attacks using precision power-fail detection and battery-isolated RTC operation. |
Use Scenario: Mission-critical flight data recording in airborne systems where GPS-denied operation requires autonomous, high-reliability timekeeping. IC Role / Device Role / Timing Role: Redundant timing reference and health-event timestamping unit - operates continuously during aircraft power transitions and emergency battery modes. Use Value: Delivers ±1.53 min/month accuracy with zero calibration required, satisfying DO-160 Section 22 environmental test requirements for airborne clocks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile RTC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS1554P-120IND+ | Same 34-pin PowerCap form factor and 3.3V operation, but lacks integrated crystal - requires external DS9034PCX mounting | Identical industrial temperature and retention specs; differs only in crystal integration method | Select DS1554P-120IND+ if sourcing flexibility for crystal replacement or qualification testing is needed |
| DS1552WP-120IND+ | Lower memory density (64kbit), same PowerCap package, identical RTC/alarm/watchdog functions and 3.3V/industrial spec | Reduced SRAM capacity suits cost-sensitive designs with minimal logging depth requirements | Choose DS1552WP-120IND+ when 8k × 8 memory suffices and BOM cost optimization is prioritized |
Compared with DS1554WP-120IND+, DS1554P-120IND+ offers identical electrical behavior but shifts crystal responsibility to the user, while DS1552WP-120IND+ trades memory capacity for lower unit cost - both retain full RTC register compatibility and industrial-grade reliability.
Availability
DS1554WP-120IND+ is available at Aetrix Electronics and suitable for industrial PLC control, medical device logging, smart energy metering, avionics health monitoring, and tamper-resistant time-stamping applications requiring stable component supply over extended product lifecycles.
Supply support for DS1554WP-120IND+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in precision analog, mixed-signal, and high-reliability timing solutions for industrial, medical, and aerospace markets.
The DS1554WP-120IND+ belongs to Maxim's legacy nonvolatile RTC family, engineered to eliminate external backup batteries and crystal circuits while delivering certified Y2K compliance and 10-year data retention in harsh environments.
FAQ
What is the primary function of the DS1554WP-120IND+?
The DS1554WP-120IND+ is a fully integrated nonvolatile timekeeping RAM that combines real-time clock/calendar, 256kbit SRAM, lithium battery, crystal oscillator, power-fail detection, and watchdog timer in a single 34-pin PowerCap module. It provides autonomous, battery-backed timekeeping and data storage without external components - making DS1554WP-120IND+ ideal for mission-critical embedded systems requiring long-term reliability.
How does the DS1554WP-120IND+ handle power failure scenarios?
DS1554WP-120IND+ uses dual voltage thresholds: VPF (2.75–2.97V) triggers automatic write protection to prevent corrupted data during brownout, while VSO (equal to VBAT or VPF) initiates seamless switchover to the internal lithium battery. This ensures uninterrupted RTC operation and SRAM data retention - verified for 10 years at +25°C - without host intervention or firmware action.
Can the DS1554WP-120IND+ be used without an external crystal?
Yes - DS1554WP-120IND+ integrates the 32.768kHz crystal within its DS9034PCX PowerCap, eliminating the need for external crystal placement or layout tuning. Unlike DIP variants (e.g., DS1554W-120IND+), the PowerCap architecture embeds the resonator directly above the IC, so DS1554WP-120IND+ operates immediately upon VCC application with no external timing components required.
What is the significance of the "IND" suffix in DS1554WP-120IND+?
The "IND" suffix in DS1554WP-120IND+ denotes industrial temperature grade operation from –40°C to +85°C, validated across the full range for all electrical parameters including VPF, tRC, ICC, and RTC accuracy. This certification ensures DS1554WP-120IND+ maintains specified performance in demanding environments such as factory floors, outdoor metering, and vehicle-mounted electronics.
How is battery health monitored in the DS1554WP-120IND+?
DS1554WP-120IND+ includes a dedicated Battery Low Flag (BLF) bit at B4 of the Flags Register (7FF0h). When BLF reads as '1', it indicates the internal lithium energy source is exhausted - signaling that RTC and SRAM data integrity can no longer be guaranteed. This hardware-monitored flag enables proactive firmware alerts before backup capability is lost, ensuring DS1554WP-120IND+ remains trustworthy throughout its service life.
DS1554WP-120IND+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 34-PowerCap™ Module
- Packaging:
- Tray
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, Leap Year, NVSRAM, Watchdog Timer, Y2K
- Memory Size:
- 32KB
- Time Format:
- HH:MM:SS (24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- Parallel
- Voltage - Supply:
- 2.97V ~ 3.63V
- Voltage - Supply, Battery:
- 3V
- Current - Timekeeping (Max):
- 4mA @ 3.3V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 34-PowerCap Module
DS1554WP-120IND+ FAQ
1.How can I place an order for DS1554WP-120IND+ through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1554WP-120IND+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for DS1554WP-120IND+ reliable?
The price and inventory of DS1554WP-120IND+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1554WP-120IND+ is usually 5 days.
3.What payment methods are accepted for DS1554WP-120IND+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1554WP-120IND+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1554WP-120IND+?
DS1554WP-120IND+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1554WP-120IND+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for DS1554WP-120IND+?
For technical support, including DS1554WP-120IND+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1554WP-120IND+ requirements.
6.How does Aetrix verify that DS1554WP-120IND+ is sourced from the original manufacturer or authorized distributors?
All DS1554WP-120IND+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that DS1554WP-120IND+ meets industry standards.
7.What is the process for return or replacement of DS1554WP-120IND+?
All DS1554WP-120IND+ units undergo pre-shipment inspection (PSI). If there is an issue with DS1554WP-120IND+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The DS1554WP-120IND+ part is unused and in its original packaging.
Return procedure for DS1554WP-120IND+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
DS1554WP-120IND+ Tags
-
MCP7940N-I/SN
Microchip Technology
-
MCP7940MT-I/MNY
Microchip Technology
-
PCF85063ATL/1,118
NXP USA Inc.
-
MCP7940NT-I/SN
Microchip Technology
-
MCP7940NT-I/MS
Microchip Technology
-
MCP7940N-I/MS
Microchip Technology
-
PCF85063AT/AY
NXP USA Inc.
-
PCF85063TP/1Z
NXP Semiconductors
-
PCF85063ATT/AJ
NXP USA Inc.
-
MCP7940NT-E/SN
Microchip Technology
-
MCP7940NT-I/MNY
Microchip Technology
-
MCP79400T-I/SN
Microchip Technology
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