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STMicroelectronics M48T08-100PC1
- Part No.:
- M48T08-100PC1
- Manufacturer:
- STMicroelectronics
- Category:
- Real Time Clocks
- Package:
- 28-DIP Module (0.600", 15.24mm)
- Datasheet:
-
M48T08-100PC1.pdf
- Description:
- IC RTC CLK/CALENDAR PAR 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,999
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Product details
Overview
M48T08-100PC1 from STMicroelectronics is a 5 V, 64 Kbit (8 Kb × 8) non-volatile TIMEKEEPER® SRAM integrating ultra-low-power static RAM, real-time clock, power-fail control circuitry, and on-board lithium battery and crystal in a CAPHAT™ DIP package. It delivers BCD-coded timekeeping (year/month/day/hour/minute/second), ±1 minute/month accuracy at 25 °C, and automatic WRITE protection during VCC drop below 4.5 V. It serves as a drop-in replacement for JEDEC-standard 8 K × 8 SRAMs in industrial control panels requiring persistent time-stamped logging during mains failure.
For engineers reviewing the M48T08-100PC1 datasheet, M48T08-100PC1 pinout, M48T08-100PC1 application, or M48T08-100PC1 equivalent, this page provides verified timing register mapping, VPFD voltage thresholds, battery-backed data retention behavior, and functional compatibility with DS1643 and standard SRAM sockets - all critical for legacy system maintenance and power-interruption resilience design.
Technical Context
The M48T08-100PC1 integrates a 32.768 kHz quartz oscillator, BiPORT™ dual-access memory array, and voltage-sense switching circuitry on a single die. Its clock registers (addresses 1FF8h–1FFFh) are mapped into the upper 8 bytes of the 8 K × 8 SRAM space and updated once per second by dedicated clock logic - not CPU-driven - ensuring atomic time reads without bus contention.
Power management operates via two distinct thresholds: VPFD (4.5 V min) triggers automatic chip deselect and WRITE protection, while VSO (typically ~4.25 V) initiates seamless switchover to internal lithium cell. The INT pin asserts an open-drain interrupt within 10–40 µs of VCC crossing VPFD, enabling host MCU to initiate controlled save operations before full backup mode engages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8 K × 8) SRAM with BYTEWIDE™ access - supports direct parallel interface like standard SRAMs without address multiplexing. |
| Clock Accuracy | ±1 minute/month at 25 °C - enables long-term timestamping in metering and data loggers without external calibration. |
| VPFD Threshold | 4.5 V ≤ VPFD ≤ 4.75 V - defines precise voltage window where automatic WRITE protect and chip deselect activate to prevent corruption during brownout. |
| Data Retention | ≥10 years on internal battery - guaranteed under VCC < VSO; eliminates need for external backup power or supercapacitors. |
| Access Time | 100 ns max (–100 speed grade) - meets timing requirements of 8 MHz Z80, 68K, and early ARM-based controllers interfacing via ISA or custom buses. |
| Package Type | PCDIP28 CAPHAT™ - fully integrated 28-pin plastic DIP housing silicon, 32.768 kHz crystal, and lithium coin cell in one hermetically sealed unit. |
| Operating Voltage | 4.75 V to 5.5 V - compatible with regulated +5 V rails common in industrial PLCs and telecom line cards. |
Pinout & Package
Package: PCDIP28 CAPHAT™ - 28-pin plastic dual in-line package with integrated lithium battery and quartz crystal. No external components required for timekeeping or data retention.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address inputs | 13-bit address bus supporting full 8 K × 8 memory map (0000h–1FFFh); clock registers reside at 1FF8h–1FFFh. |
| DQ0–DQ7 | Data I/O bidirectional bus | 8-bit parallel data path; supports simultaneous READ/WRITE of time registers and SRAM cells using standard SRAM timing. |
| E1, E2 | Chip enable inputs | Active-low (E1) and active-high (E2) dual CE scheme enables flexible bus decoding; both must be asserted for memory access. |
| G | Output enable | Controls three-state output drivers; high-Z when inactive to prevent bus contention during interrupt or standby. |
| W | WRITE enable | Active-low signal controlling WRITE cycles; low pulse duration ≥80 ns required for reliable register or SRAM write. |
| INT | Open-drain power-fail interrupt | Asserts within 10–40 µs of VCC falling into VPFD window; requires external pull-up; signals host to save state pre-backup. |
| VCC, VSS | Power supply and ground | Single 5 V supply; internal voltage monitor disconnects VCC and switches to battery when VCC < VSO (~4.25 V). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated CAPHAT™ packaging | Eliminates board-level battery holders, crystal load capacitors, and backup diodes - reduces BOM count and assembly steps in legacy designs. |
| BYTEWIDE™ clock register mapping | Time data (BCD year/month/day/hour/min/sec) resides in standard SRAM address space (1FF8h–1FFFh), enabling read/write using existing memory-mapped I/O routines. |
| Software-controlled clock calibration | Control register bit adjusts oscillator trim digitally - enables field correction of aging or temperature drift without hardware modification. |
| Automatic power-fail WRITE protection | Hardware-enforced lockout prevents partial writes during brownout; no firmware intervention needed to ensure data integrity across power cycles. |
| Pin/function compatibility with DS1643 | Direct socket replacement in legacy systems designed for Dallas Semiconductor TIMEKEEPER® parts - preserves PCB layout and firmware. |
Applications
| Industrial Data Logger | Legacy PLC Real-Time Clock |
|---|---|
|
Use Scenario: Standalone environmental sensor node recording temperature/humidity every 5 minutes with timestamped entries stored in local SRAM. IC Role / Device Role / Timing Role: Non-volatile time source and storage buffer - maintains accurate wall-clock time and logs during AC mains outage using internal battery. Use Value: Eliminates need for external RTC + EEPROM combo; guarantees timestamp continuity and data coherency across >10-year deployments without maintenance. |
Use Scenario: Retrofit upgrade of 1990s programmable logic controller where original DS1643 failed and board space prohibits redesign. IC Role / Device Role / Timing Role: Pin-compatible TIMEKEEPER® replacement - restores scheduled task execution, event logging, and HMI time display without PCB rework. Use Value: Reduces downtime and engineering cost by enabling direct socket replacement while preserving firmware and timing-critical ladder logic sequences. |
| Energy Meter Firmware Timestamping | Medical Device Power-Fail Logging |
|
Use Scenario: Electricity meter storing tamper events, voltage sags, and kWh accumulation with precise UTC-aligned timestamps. IC Role / Device Role / Timing Role: Secure time anchor and non-volatile scratchpad - clocks remain synchronized and SRAM contents retained during grid instability or battery swap. Use Value: Meets IEC 62053-21 traceability requirements by guaranteeing timestamp integrity independent of main power or microcontroller uptime. |
Use Scenario: Portable infusion pump logging occlusion alarms, dose delivery history, and battery discharge cycles for regulatory audit trails. IC Role / Device Role / Timing Role: Fail-safe timekeeper and event buffer - continues timestamping and storing critical alerts even if main MCU resets or loses power. Use Value: Ensures FDA 21 CFR Part 11 compliance by providing immutable, battery-backed time stamps for all safety-critical operational events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar non-volatile timekeeping SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS1643-100+ (Maxim) | Same pinout and function, but uses external battery and crystal; no integrated CAPHAT™ package; requires board-level capacitor and holder. | Suitable only where board redesign is possible and space allows discrete backup components. | Select only if CAPHAT™ integration is unnecessary and legacy DS1643 footprint must be preserved with minimal change. |
| M48T08Y-100PC1 (STMicro) | Identical core functionality but wider VCC range (4.5–5.5 V) and lower VPFD (4.2–4.5 V); same PCDIP28 CAPHAT™ package. | Better suited for systems with looser 5 V regulation or earlier brownout detection requirements. | Prefer when operating near 4.5 V minimum or when tighter VPFD margin improves system robustness against ripple-induced false triggers. |
Compared with DS1643-100+, M48T08-100PC1 reduces bill-of-materials and assembly risk via integrated battery/crystal; compared with M48T08Y-100PC1, it trades slightly narrower VCC tolerance for higher VPFD threshold - simplifying power-monitoring design in stable 5 V environments.
Availability
M48T08-100PC1 is available at Aetrix Electronics and suitable for industrial data loggers, legacy PLC upgrades, energy meter firmware timestamping, and medical device power-fail logging requiring stable component supply across extended product lifecycles.
Supply support for M48T08-100PC1 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 headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management ICs with strong heritage in mixed-signal and non-volatile memory solutions.
The TIMEKEEPER® product line was developed to deliver integrated, battery-backed real-time clock and memory functions in legacy-compatible packages - specifically targeting long-lifecycle industrial and infrastructure equipment requiring decades of field reliability without redesign.
FAQ
What is the battery lifetime specification for M48T08-100PC1 under continuous backup conditions?
The internal lithium cell guarantees ≥10 years of data and clock retention when VCC remains below VSO (~4.25 V). This rating assumes typical operating temperature (0–70 °C) and accounts for self-discharge; actual endurance may exceed 12 years at 25 °C per AN1012. Battery life is not user-replaceable due to CAPHAT™ hermetic sealing.
How does the M48T08-100PC1 handle leap year and month-end date rollover?
The hardware clock logic automatically corrects for 28-, 29- (leap year, valid through 2100), 30-, and 31-day months using built-in calendar logic. No firmware intervention is required - the BCD-encoded day register advances correctly after February 28 in non-leap years and February 29 in leap years, maintaining ISO 8601 compliance.
Can the INT pin be left unconnected if power-fail interrupt functionality is unused?
No - the INT pin is an open-drain output requiring an external pull-up resistor (typically 4.7 kΩ to VCC) regardless of usage. Leaving it floating violates the datasheet's absolute maximum ratings and risks spurious interrupts or latch-up due to noise coupling into the undriven node.
Is software calibration of the oscillator supported, and how is it implemented?
Yes - calibration is performed by writing a 7-bit trim value to bits 0–6 of the clock control register (1FF8h, bit 0–6). Each LSB adjusts frequency by ~0.2 ppm; full range covers ±127 ppm. Calibration persists across power cycles and requires no external components - enabling field correction for aging or thermal drift.
M48T08-100PC1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- Timekeeper®
- Package/Case:
- 28-DIP Module (0.600", 15.24mm)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Leap Year, Watchdog Timer
- Memory Size:
- -
- Time Format:
- HH:MM:SS (24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- Parallel
- Voltage - Supply:
- 4.75V ~ 5.5V
- Voltage - Supply, Battery:
- -
- Current - Timekeeping (Max):
- 3mA @ 4.7V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 28-PCDIP, CAPHAT®
M48T08-100PC1 FAQ
1.How can I place an order for M48T08-100PC1 through Aetrix?
Please submit a Request for Quotation (RFQ) for M48T08-100PC1 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 M48T08-100PC1 reliable?
The price and inventory of M48T08-100PC1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M48T08-100PC1 is usually 5 days.
3.What payment methods are accepted for M48T08-100PC1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M48T08-100PC1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M48T08-100PC1?
M48T08-100PC1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M48T08-100PC1 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 M48T08-100PC1?
For technical support, including M48T08-100PC1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M48T08-100PC1 requirements.
6.How does Aetrix verify that M48T08-100PC1 is sourced from the original manufacturer or authorized distributors?
All M48T08-100PC1 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 M48T08-100PC1 meets industry standards.
7.What is the process for return or replacement of M48T08-100PC1?
All M48T08-100PC1 units undergo pre-shipment inspection (PSI). If there is an issue with M48T08-100PC1, 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 M48T08-100PC1 part is unused and in its original packaging.
Return procedure for M48T08-100PC1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
M48T08-100PC1 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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