My Inquiry
My Account
STMicroelectronics M41T93RMY6E
- Part No.:
- M41T93RMY6E
- Manufacturer:
- STMicroelectronics
- Category:
- Real Time Clocks
- Package:
- 18-SOX, 18-SOIC with Crystal (7.5mm Width)
- Datasheet:
-
M41T93RMY6E.pdf
- Description:
- IC RTC CLK/CALENDAR SPI 18SOX
- Quantity:
- Payment:
- Shipping:
Inventory:2,333
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
M41T93RMY6E from STMicroelectronics is a serial SPI real-time clock (RTC) with integrated 32.768 kHz oscillator, battery switchover circuitry, and 7-byte user SRAM. It delivers ±5 ppm factory-calibrated accuracy (SOX18), ultra-low 365 nA battery supply current, and operates across 2.7 V to 5.5 V VCC. Used in industrial control panels for timestamped event logging with battery-backed timekeeping during main power loss.
For engineers reviewing the M41T93RMY6E datasheet, M41T93RMY6E pinout, M41T93RMY6E application, or M41T93RMY6E equivalent, key selection criteria include backup-mode alarm interrupt persistence, programmable analog/digital calibration registers, SQW output frequency configurability, and VSO = VRST = 2.63 V switchover threshold.
Technical Context
The M41T93RMY6E implements a BCD-formatted calendar engine with automatic leap-year and month-end correction, supported by dedicated tenths/hundredths-of-second counters and century bits. Its SPI interface strictly supports Mode 0 (CPOL = 0, CPHA = 0), with SDI latched on SCL rising edge and SDO shifted on falling edge.
Power management includes dual-threshold switchover (VSO = VRST = 2.63 V), oscillator fail detection with interrupt enable, and write protection activation during VCC recovery until tREC (≥100 ms) elapses. The device maintains register coherency during read/write via atomic access protocols and halt-bit-controlled clock freezing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Battery supply current | 365 nA - enables >10-year coin-cell operation (CR2032) without compromising timekeeping integrity during backup mode |
| Accuracy (post-reflow) | ±5 ppm typical - achieved via factory-trimmed analog load capacitance and digital periodic counter correction circuits |
| VCC operating range | 2.7 V to 5.5 V - matches industrial 3.3 V and 5 V logic rails while supporting brown-out tolerant operation |
| Switchover voltage (VSO/VRST) | 2.63 V - triggers seamless transition to battery before system reset, preserving RTC state and alarm functionality |
| SPI interface mode | Mode 0 only (CPOL = 0, CPHA = 0) - ensures deterministic timing alignment with legacy microcontrollers lacking configurable SPI polarity/phase |
| Square wave output | Default 32 kHz, programmable to 1 Hz–32 kHz - provides flexible clock source for microcontroller wake-up or external timing without added components |
| User SRAM | 7 bytes battery-backed - retains critical configuration or fault logs across power cycles without external EEPROM |
Pinout & Package
Package: SOX18 - 18-lead plastic SOIC (11.61 × 7.62 mm) with embedded 32.768 kHz crystal. Requires external battery connection to VBAT for non-volatile operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| E | Chip enable | Active-low SPI slave select; must transition high→low before each command sequence |
| SDI | Serial data input | Latches instruction/address/data on SCL rising edge; supports 8-bit register writes and command framing |
| SDO | Serial data output | Drives data on SCL falling edge; remains high-Z when E is high or during internal address increment |
| SCL | Serial clock input | Provides synchronous timing for all SPI transfers; max frequency 1 MHz per AC specs |
| IRQ/FT/OUT | Open-drain interrupt/frequency test/output | Asserts low on alarm, watchdog timeout, or oscillator fail; supports wired-OR interrupt aggregation |
| RST | Power-on reset output | Open-drain active-low signal synchronized to VCC rise above VPFD; used for system-level reset coordination |
| SQW | Square wave output | Programmable-frequency CMOS output (default 32 kHz); independent of SPI activity and backup mode |
| VBAT | Battery supply input | Accepts 1.8 V–5.5 V backup source; powers RTC core when VCC < 2.63 V; tie to VSS if unused |
| VCC | Main supply voltage | 2.7 V–5.5 V operating rail; powers digital logic, SPI interface, and calibration circuitry |
| VSS | Ground reference | Common return path for VCC, VBAT, and all I/O; requires low-impedance PCB connection |
Key Features
| Feature | Design Value |
|---|---|
| Dual programmable alarms | Alarm 1 and optional Alarm 2 both generate IRQ/FT/OUT interrupts valid in battery backup mode, enabling time-triggered actions during main power loss |
| On-chip calibration | Separate 8-bit digital correction register (±127 ppm step) and 5-bit analog load capacitance register (0–31 pF) allow field tuning to compensate for crystal aging and temperature drift |
| Watchdog + timer | Configurable watchdog timer prevents firmware lockup; independent 8-bit countdown timer supports periodic wake-up or interval measurement with interrupt flag (TF) and enable (TE) |
| Oscillator fail detection | Dedicated circuit monitors 32.768 kHz oscillation and asserts IRQ/FT/OUT within 1 second of stoppage, with OFIE bit enabling interrupt generation |
| Battery low warning | Internal comparator flags VBAT < 1.8 V via BL bit in flags register, allowing host MCU to log low-battery condition before RTC failure |
Applications
| Industrial Data Logger | Medical Device Timestamping |
|---|---|
|
Use Scenario: Continuous environmental monitoring in remote substations with intermittent mains power and CR2032 backup. IC Role / Device Role / Timing Role: Primary time-of-day clock/calendar with battery-switchover, maintaining accurate timestamps during grid outages. Use Value: Preserves sub-second event sequencing across power cycles using 7-byte SRAM and coherent BCD register reads, eliminating timestamp gaps. |
Use Scenario: Portable infusion pump recording drug delivery events and operator interactions across multiple battery charge cycles. IC Role / Device Role / Timing Role: Non-volatile timekeeper providing ISO 13485-compliant audit trail timestamps with alarm-driven alert escalation. Use Value: Guarantees traceable, battery-backed time stamps even during deep sleep or main battery replacement, meeting medical regulatory requirements. |
| Smart Energy Meter | Building Automation Controller |
|
Use Scenario: Utility meter capturing kWh consumption at 15-minute intervals, storing time-stamped data during nightly RF transmission blackouts. IC Role / Device Role / Timing Role: High-accuracy RTC with programmable 15-minute alarm interrupt driving data logging and communication scheduling. Use Value: Delivers ±5 ppm accuracy over –40 °C to +85 °C, ensuring billing-grade time consistency without external calibration hardware. |
Use Scenario: HVAC controller synchronizing zone schedules, occupancy sensing, and energy reporting across seasonal temperature swings. IC Role / Device Role / Timing Role: Central time base for coordinated system-wide events, including daylight savings adjustment and maintenance alerts. Use Value: Automatic leap-year and month-end correction eliminates manual date rollover errors; SQW output drives external real-time display. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar real-time clock applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS3231SN#T&R | Higher accuracy (±2 ppm), integrated TCXO, but no user SRAM and higher 1.3 μA battery current | Preferred where absolute precision outweighs battery life; lacks 7-byte SRAM for local event storage | Select for metrology-grade timing; avoid when >5-year coin-cell life or local data retention is required |
| PCF8563T | I²C interface only, no SPI support; lower accuracy (±25 ppm), no analog/digital calibration registers | Suitable for cost-sensitive consumer devices with I²C infrastructure; cannot replace SPI-based designs without firmware changes | Choose only for new I²C-only designs; not a drop-in replacement due to protocol and calibration capability gaps |
Compared with DS3231SN#T&R and PCF8563T, the M41T93RMY6E uniquely balances ultra-low battery current (365 nA), SPI compatibility, field-calibratable accuracy, and integrated SRAM-making it optimal for industrial systems requiring long-life backup, deterministic interface timing, and local timestamp storage.
Availability
M41T93RMY6E is available at Aetrix Electronics and suitable for industrial data loggers, medical device timestamping, and smart energy meters requiring stable component supply across extended product lifecycles.
Supply support for M41T93RMY6E 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 microcontrollers, power management ICs, sensors, and timing solutions for industrial, automotive, and consumer markets.
The M41T93 belongs to ST's real-time clock portfolio engineered for high-reliability, battery-critical applications-emphasizing ultra-low power, embedded crystal integration, and robust switchover logic for uninterrupted timekeeping.
FAQ
What is the VSO/VRST voltage threshold for M41T93RMY6E?
The M41T93RMY6E uses a fixed switchover and reset threshold of 2.63 V (R-suffix variant). When VCC drops below this level, the device immediately disconnects from VCC and switches to VBAT, preserving RTC registers and alarm functionality. This value is laser-trimmed at wafer test and does not require external resistor networks.
Does M41T93RMY6E support SPI Mode 3 (CPOL = 1, CPHA = 1)?
No. The M41T93RMY6E supports SPI Mode 0 only (CPOL = 0, CPHA = 0), as confirmed in Section 1.1.3 and Figure 6 of the datasheet. Attempting Mode 3 will result in misaligned data sampling-SDI latching on wrong clock edges and SDO output skew-causing register corruption or communication failure.
How is the embedded crystal configured in the SOX18 package?
The SOX18 package integrates a factory-tuned 32.768 kHz quartz crystal directly into the leadframe cavity, eliminating external crystal placement and load capacitor selection. This reduces board area by ~12 mm² and removes sensitivity to PCB layout parasitics, delivering guaranteed ±5 ppm accuracy after two reflows without user trimming.
Can the 7-byte user SRAM retain data during VCC power loss?
Yes. The 7-byte SRAM is powered exclusively by VBAT when VCC falls below VRST (2.63 V). Data retention is guaranteed down to 1.8 V VBAT and across the full –40 °C to +85 °C operating temperature range, with no refresh required. SRAM contents remain intact for >10 years on a fresh CR2032 cell under typical conditions.
M41T93RMY6E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 18-SOX, 18-SOIC with Crystal (7.5mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, Leap Year, Square Wave Output, SRAM, Watchdog Timer
- Memory Size:
- 7B
- Time Format:
- HH:MM:SS:hh (24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- SPI
- Voltage - Supply:
- 2.7V ~ 5.5V
- Voltage - Supply, Battery:
- 1.8V ~ 5.5V
- Current - Timekeeping (Max):
- 10µA @ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 18-SOX
M41T93RMY6E FAQ
1.How can I place an order for M41T93RMY6E through Aetrix?
Please submit a Request for Quotation (RFQ) for M41T93RMY6E 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 M41T93RMY6E reliable?
The price and inventory of M41T93RMY6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M41T93RMY6E is usually 5 days.
3.What payment methods are accepted for M41T93RMY6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M41T93RMY6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M41T93RMY6E?
M41T93RMY6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M41T93RMY6E 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 M41T93RMY6E?
For technical support, including M41T93RMY6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M41T93RMY6E requirements.
6.How does Aetrix verify that M41T93RMY6E is sourced from the original manufacturer or authorized distributors?
All M41T93RMY6E 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 M41T93RMY6E meets industry standards.
7.What is the process for return or replacement of M41T93RMY6E?
All M41T93RMY6E units undergo pre-shipment inspection (PSI). If there is an issue with M41T93RMY6E, 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 M41T93RMY6E part is unused and in its original packaging.
Return procedure for M41T93RMY6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
M41T93RMY6E 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
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
