STMicroelectronics M48T08-150PC1

Overview

M48T08-150PC1 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 ±1 minute/month clock accuracy at 25 °C, supports BYTEWIDE™ RAM-like access to BCD-coded time registers (year, month, day, hour, minute, second), and provides automatic write protection during VCC drop below 4.5 V. It is used in industrial control panels requiring persistent time-stamped logging during mains failure.

For engineers reviewing the M48T08-150PC1 datasheet, M48T08-150PC1 pinout, M48T08-150PC1 application, or M48T08-150PC1 equivalent, key selection considerations include its integrated CAPHAT™ DIP mechanical integration, VPFD threshold of 4.5 V ≤ VPFD ≤ 4.75 V, battery-backed data retention for ≥10 years, and pin/function compatibility with DS1643 and JEDEC 8 K × 8 SRAMs.

Technical Context

The device integrates a 32.768 kHz quartz oscillator, BiPORT™ dual-port SRAM array (8184 × 8), voltage-sense switching circuitry, and lithium cell into a single monolithic die. Clock updates occur once per second to eight dedicated memory-mapped registers (1FF8h–1FFFh), accessible via standard SRAM read/write cycles without special timing.

Power management includes a two-threshold detection system: VPFD (power-fail deselect) triggers write protection and high-Z outputs when VCC falls within 4.5–4.75 V, while VSO (switchover) activates battery backup below ~4.25 V. The open-drain INT pin asserts within 10–40 µs of VCC crossing VPFD, enabling host MCU interrupt-driven fail-safe response.

Key Specifications

Pinout & Package

PCDIP28 CAPHAT™ package: 28-pin plastic DIP (600 mil width) with integrated lithium battery and 32.768 kHz crystal housed in molded cap; no external components needed for timekeeping or data retention.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar non-volatile RTC+SRAM applications.

Compared with DS1643-150+, M48T08-150PC1 reduces bill-of-materials and assembly risk via integrated CAPHAT™; compared with M48T35Y-150PC1, it lowers unit cost and power consumption while retaining identical timekeeping accuracy and fail-safe behavior for 8 KB applications.

Availability

M48T08-150PC1 is available at Aetrix Electronics and suitable for industrial control panels, smart energy meters, medical device logs, and building automation controllers requiring stable component supply with guaranteed 10-year data retention and ±1 minute/month RTC accuracy.

Supply support for M48T08-150PC1 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, designing and manufacturing analog, microcontroller, power, and memory solutions for industrial, automotive, and consumer markets.

M48T08 belongs to ST's TIMEKEEPER® family-engineered specifically for systems needing tamper-resistant, battery-backed real-time clock and non-volatile memory in a single IC, targeting applications where power reliability and timestamp integrity are mission-critical.

FAQ

What is the battery lifetime under continuous backup conditions?

The internal lithium button cell in the PCDIP28 CAPHAT™ package sustains SRAM and RTC operation for a minimum of 10 years when VCC remains below VSO (~4.25 V). This rating assumes typical operating temperature (0–70 °C) and accounts for self-discharge; actual life may exceed 12 years at 25 °C per AN1012 test data.

How does the M48T08-150PC1 handle leap years and month-end rollovers?

Hardware logic automatically adjusts day counters for 28-, 29- (leap year), 30-, and 31-day months without firmware involvement. Leap-year calculation is valid through year 2100 per IEC 62053-21 compliance; the century bit is not implemented, so post-2100 behavior requires external handling.

Can the INT pin be left unconnected if not used?

No-the INT pin is an open-drain output and requires an external pull-up resistor (typically 4.7 kΩ to VCC) even when unused. Leaving it floating risks spurious interrupts due to noise coupling, which may trigger unintended MCU wakeups or state transitions during normal operation.

Is the M48T08-150PC1 RoHS compliant and lead-free?

Yes-M48T08-150PC1 is RoHS compliant with lead-free second-level interconnects per Directive 2011/65/EU. The PCDIP28 package uses matte tin lead finish, and all internal materials meet STMicroelectronics' Eco-Design specifications (Doc ID 2411 Rev 11, Section 8).