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STMicroelectronics M48T248Y-70PM1
- Part No.:
- M48T248Y-70PM1
- Manufacturer:
- STMicroelectronics
- Category:
- Real Time Clocks
- Package:
- 32-DIP Module (0.600", 15.24mm)
- Datasheet:
-
M48T248Y-70PM1.pdf
- Description:
- IC RTC PHANTOM CHIP PAR 32DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,537
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Product details
Overview
M48T248Y-70PM1 from STMicroelectronics is a 128K × 8 non-volatile TIMEKEEPER® SRAM with integrated real-time clock (RTC), lithium battery backup, and Phantom Clock serial interface. It operates at 5.0 V (VPFD = 4.25–4.50 V), delivers ±1 minute/month RTC accuracy at 25°C, retains data >10 years without power, and supports 12/24-hour time format with automatic leap-year correction through year 2100. It replaces volatile SRAM or EEPROM in embedded systems requiring persistent timekeeping and memory.
For engineers reviewing the M48T248Y-70PM1 datasheet, M48T248Y-70PM1 pinout, M48T248Y-70PM1 application, or M48T248Y-70PM1 equivalent, key selection criteria include battery-backed RTC + SRAM integration, DIP-32 mechanical compatibility, 70 ns memory access time, Phantom Clock register access protocol, and power-fail deselect voltage threshold for industrial power monitoring.
Technical Context
The device integrates a 32.768 kHz crystal oscillator, BCD-formatted RTC registers (8×8 bits), and 131,072-word × 8-bit NV SRAM in a single PMDIP32 module. Its Phantom Clock interface uses a deterministic 64-bit pattern-matching sequence over DQ0 to enable serial access to time registers without dedicated control pins.
Power management includes dual-threshold detection: VPFD triggers write protection during brownout, while VSO (battery switchover voltage) activates internal lithium cell when VCC drops below ~3.0 V. All RTC and SRAM functions remain fully operational under battery power with no external components required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 128K × 8 (131,072 words × 8 bits); directly replaces standard 128K SRAM without redesign. |
| RTC Accuracy | ±1 minute/month at 25°C; factory-calibrated oscillator eliminates field calibration overhead. |
| Access Time (tACC) | 70 ns max; enables direct interface with legacy 8-bit microcontrollers running ≤14 MHz. |
| Power-Fail Deselect (VPFD) | 4.25–4.50 V; ensures reliable write-protection initiation during 5 V supply sag before data corruption. |
| Data Retention | >10 years at 25°C on internal battery; supports long-life industrial equipment without maintenance. |
| Operating Voltage | 4.5–5.5 V; full 10% VCC tolerance simplifies power supply design and improves noise immunity. |
| Leap-Year Correction | Valid through year 2100; handles February 29 logic automatically including century rules. |
Pinout & Package
Package: PMDIP32 (32-pin Plastic Module Dual In-line Package), 0.6-inch width, through-hole mounting. Integrated lithium battery and crystal reside internally; no external components needed for RTC operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A16 | Address Inputs | 17-bit address bus for 131,072-word memory space; A0 = LSB, A16 = MSB. |
| DQ0–DQ7 | Data I/O (bidirectional) | 8-bit parallel data path; DQ0 carries Phantom Clock serial bit-stream during pattern recognition. |
| CE | Chip Enable | Active-low memory enable; also controls Phantom Clock access initiation and timing sequence. |
| OE | Output Enable | Active-low output driver control; determines READ vs. Phantom Clock data transfer mode. |
| WE | Write Enable | Active-low write strobe; used in 64-cycle Phantom Clock pattern matching and memory writes. |
| RST | Reset Input | Asynchronous reset; configurable via clock register bit to ignore or assert on low pulse. |
| VCC | Supply Voltage | 5 V main power input; monitored for VPFD and VSO thresholds to manage battery switchover. |
| VSS | Ground | Signal and power ground reference for all digital and RTC circuitry. |
Key Features
| Feature | Design Value |
|---|---|
| Phantom Clock Interface | 64-bit pattern-matched serial access over DQ0 eliminates need for dedicated RTC control lines or I²C/SPI peripherals. |
| Integrated Lithium Backup | Self-contained battery provides uninterrupted RTC and SRAM retention for >10 years-no external coin cell or charging circuit required. |
| Automatic Calendar Logic | Hardware-level day-of-month adjustment, month-end rollover, and leap-year correction through year 2100 reduce firmware overhead. |
| Power-Fail Protection | Dual-threshold detection (VPFD + VSO) guarantees write disable before brownout and seamless battery switchover without glitch or reset. |
| BCD Time Registers | Eight 8-bit BCD registers (seconds to year) simplify time parsing and display formatting in resource-constrained MCUs. |
Applications
| Industrial PLCs | Point-of-Sale Terminals |
|---|---|
|
Use Scenario: Maintaining accurate timestamped transaction logs and system uptime counters across unattended multi-year deployments. IC Role / Device Role / Timing Role: Non-volatile time source and event-logging memory co-located on main controller board. Use Value: Eliminates reliance on network time sync or external RTC modules, ensuring audit-trail integrity during network outages or power loss. |
Use Scenario: Recording sales timestamps, shift start/end times, and fiscal period closures in retail environments with intermittent AC power. IC Role / Device Role / Timing Role: Battery-backed RTC + memory subsystem managing local timekeeping and receipt buffer storage. Use Value: Guarantees legally compliant time-stamping of financial transactions even during extended blackouts-no data loss or clock drift. |
| Medical Infusion Pumps | Energy Metering Devices |
|
Use Scenario: Logging therapy delivery timestamps, alarm events, and calibration history in Class II medical devices requiring FDA-compliant traceability. IC Role / Device Role / Timing Role: Tamper-resistant timekeeping and audit log storage within sealed, battery-powered enclosure. Use Value: Provides IEC 62304-compliant time stamping with >10-year data retention-meets regulatory requirements for device lifecycle records. |
Use Scenario: Capturing kWh consumption intervals, tariff switching events, and tamper alerts in utility-grade smart meters operating 20+ years. IC Role / Device Role / Timing Role: Primary time base and secure event memory for revenue-grade metering firmware. Use Value: Delivers NIST-traceable time accuracy (±1 min/month) and guaranteed 10-year retention without supercapacitors or service interventions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar non-volatile RTC + SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS12887A-120IND+ | 5 V-only, 128K × 8 NV SRAM, same DIP-24 package but lacks Phantom Clock; uses parallel register map. | Requires additional address decoding logic and separate RTC control lines; no serial pattern-matching interface. | Select when legacy DS12887 firmware compatibility is required and PCB layout cannot accommodate DIP-32. |
| M48T35AV-10PC1 | 3.3 V variant (VPFD = 2.80–2.97 V), identical Phantom Clock architecture and pinout, but slower 100 ns access time. | Designed for mixed-voltage 3.3 V systems; requires level-shifting if interfaced with 5 V controllers. | Select for new 3.3 V designs where lower power and modern supply rails outweigh speed requirements. |
Compared with DS12887A-120IND+, M48T248Y-70PM1 offers superior integration via Phantom Clock and longer data retention; compared with M48T35AV-10PC1, it delivers faster timing and higher noise margin in 5 V industrial environments.
Availability
M48T248Y-70PM1 is available at Aetrix Electronics and suitable for industrial PLCs, point-of-sale terminals, medical infusion pumps, and energy metering devices requiring stable component supply across extended product lifecycles.
Supply support for M48T248Y-70PM1 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
STMicroelectronics is a global semiconductor leader specializing in automotive, industrial, and power management ICs, with broad analog, MCU, and memory portfolios.
M48T248Y-70PM1 belongs to the TIMEKEEPER® family-designed specifically for embedded systems needing self-contained, battery-backed RTC + SRAM in a single DIP module with zero external components.
FAQ
What is the Phantom Clock interface, and how does it differ from standard RTC communication?
The Phantom Clock is a proprietary serial interface that uses a deterministic 64-bit pattern written to DQ0 across consecutive WRITE cycles to unlock access to RTC registers. Unlike I²C or SPI, it requires no dedicated clock or control pins-only CE, WE, OE, and DQ0-reducing PCB routing complexity and pin count on host microcontrollers.
How is battery backup managed, and what is the expected lifetime under continuous operation?
An integrated lithium cell powers the RTC and SRAM when VCC drops below VSO (~3.0 V). ST specifies >10 years of data retention at 25°C with the oscillator active and no VCC applied. Actual lifetime extends significantly when VCC is present most of the time, as battery discharge only occurs during power loss events.
Can the M48T248Y-70PM1 be used in new designs despite its obsolete status?
Yes-Aetrix Electronics maintains active inventory and long-term supply agreements for M48T248Y-70PM1 to support legacy system maintenance and new industrial designs where its DIP-32 form factor, proven reliability, and integrated battery backup provide critical advantages over newer surface-mount alternatives.
What happens during a power failure, and how is data corruption prevented?
When VCC falls below VPFD (4.25–4.50 V), write protection engages immediately-blocking all memory and RTC writes. At VSO (~3.0 V), the device switches to battery power without interruption. All control signals (CE, OE, WE) are ignored during switchover, preventing partial writes or bus contention that could corrupt time or memory contents.
M48T248Y-70PM1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- Timekeeper®
- Package/Case:
- 32-DIP Module (0.600", 15.24mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Phantom Time Chip
- Features:
- Leap Year
- Memory Size:
- -
- Time Format:
- HH:MM:SS:hh (12/24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- Parallel
- Voltage - Supply:
- 4.5V ~ 5.5V
- Voltage - Supply, Battery:
- -
- Current - Timekeeping (Max):
- 5mA @ 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 32-PMDIP
M48T248Y-70PM1 FAQ
1.How can I place an order for M48T248Y-70PM1 through Aetrix?
Please submit a Request for Quotation (RFQ) for M48T248Y-70PM1 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 M48T248Y-70PM1 reliable?
The price and inventory of M48T248Y-70PM1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M48T248Y-70PM1 is usually 5 days.
3.What payment methods are accepted for M48T248Y-70PM1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M48T248Y-70PM1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M48T248Y-70PM1?
M48T248Y-70PM1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M48T248Y-70PM1 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 M48T248Y-70PM1?
For technical support, including M48T248Y-70PM1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M48T248Y-70PM1 requirements.
6.How does Aetrix verify that M48T248Y-70PM1 is sourced from the original manufacturer or authorized distributors?
All M48T248Y-70PM1 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 M48T248Y-70PM1 meets industry standards.
7.What is the process for return or replacement of M48T248Y-70PM1?
All M48T248Y-70PM1 units undergo pre-shipment inspection (PSI). If there is an issue with M48T248Y-70PM1, 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 M48T248Y-70PM1 part is unused and in its original packaging.
Return procedure for M48T248Y-70PM1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
M48T248Y-70PM1 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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