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STMicroelectronics M41T93ZMY6E
- Part No.:
- M41T93ZMY6E
- Manufacturer:
- STMicroelectronics
- Category:
- Real Time Clocks
- Package:
- 18-SOX, 18-SOIC with Crystal (7.5mm Width)
- Datasheet:
-
M41T93ZMY6E.pdf
- Description:
- IC RTC CLK/CALENDAR SPI 18SOX
- Quantity:
- Payment:
- Shipping:
Inventory:2,588
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Product details
Overview
M41T93ZMY6E from STMicroelectronics is a serial SPI real-time clock (RTC) with integrated 32.768 kHz oscillator, battery switchover circuitry, and 7-byte SRAM. It delivers ±5 ppm factory-calibrated accuracy (SOX18), ultra-low 365 nA battery current, 2.38–5.5 V operating range, and supports SPI Mode 0 (CPOL=0, CPHA=0). Used in industrial control panels for time-stamped event logging under intermittent power.
For engineers reviewing the M41T93ZMY6E datasheet, M41T93ZMY6E pinout, M41T93ZMY6E application, or M41T93ZMY6E equivalent, key selection criteria include backup voltage threshold (VSO = 2.32 V), programmable analog/digital calibration, alarm interrupt persistence during battery mode, and QFN16 package compatibility with embedded crystal alternatives.
Technical Context
The M41T93ZMY6E implements a BCD-formatted RTC core with automatic leap-year correction and century-bit handling (CB1:CB0), synchronized via SPI Mode 0 interface with E/SDI/SCL/SDO signals and open-drain IRQ/FT/OUT and RST outputs. Its oscillator fail detection monitors 32.768 kHz crystal stability and triggers interrupt on stop condition.
Power management includes dual-threshold switchover (VSO = VRST = 2.32 V), write protection during brown-out recovery (tREC delay), and battery-backed register retention. Calibration uses both digital counter correction (±127 ppm adjustment) and analog load capacitance tuning (0–12.5 pF in 0.5 pF steps) to achieve sub-ppm drift compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Battery Current | 365 nA - enables >10-year coin-cell operation (CR2032) without recharge |
| Accuracy | ±5 ppm typical after 2 reflows - ensures ≤2.6 sec/month drift in SOX18 configuration |
| VCC Range | 2.38 V to 5.5 V - supports direct connection to 3.3 V or 5 V rails without LDO |
| SPI Mode | Mode 0 only (CPOL=0, CPHA=0) - requires MCU SPI peripheral configured for leading-edge sampling |
| Backup Switchover | VSO = VRST = 2.32 V - guarantees seamless transition before system brown-out resets MCU |
| Square Wave Output | Default 32.768 kHz, programmable to 1 Hz–32 kHz - provides precise timing reference for microcontroller wake-up or sensor sampling |
| User SRAM | 7 bytes battery-backed - retains critical state (e.g., last fault code, calibration offset) across main power loss |
Pinout & Package
Package: QFN16, 4 mm × 4 mm, no-lead, exposed pad. Pin 1 marked by dot; pins 1–8 top row left-to-right, 9–16 bottom row right-to-left (per Figure 2, DocID12615 Rev 8).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| XO | Oscillator output | Drives external 32.768 kHz crystal (QFN16 only); not connected in SOX18 variant |
| XI | Oscillator input | Accepts crystal feedback signal; internal load caps configurable via analog calibration register |
| IRQ/FT/OUT | Open-drain multifunction output | Delivers alarm, watchdog, or timer interrupt; supports frequency test mode when VCC active |
| SQW | Programmable square wave output | Defaults to 32.768 kHz on power-up; configurable via SQWE bit and frequency select bits |
| RST | Open-drain reset output | Asserts low during power-on reset (tREC delay); synchronizes system MCU reset with RTC initialization |
| E | Chip enable input | Active-low SPI slave select; high-Z SDO when E = high; requires falling edge to initiate transaction |
| SDI | Serial data input | Latches command/address/data on rising SCL edge; supports 8-bit read/write sequences |
| SDO | Serial data output | Shifts register contents on falling SCL edge; tri-states when E = high |
| SCL | Serial clock input | Provides synchronous timing; must meet tSU, tH, tV timing per Table 22 (min 100 ns pulse width) |
| VBAT | Battery supply input | Connects to coin cell (e.g., CR2032); powers RTC during VCC dropout; internal diode prevents backfeed |
Key Features
| Feature | Design Value |
|---|---|
| Dual-alarm interrupt with repeat modes | Alarm 1 + optional Alarm 2 support daily, monthly, or match-all registers; both assert IRQ/FT/OUT in battery mode |
| Watchdog timer with auto-clear | Configurable timeout (256 ms–4.25 hrs); resets system if not serviced; prevents firmware lockup in unattended devices |
| Programmable 8-bit countdown timer | Seven selectable clock sources (32.768 kHz down to 244.1 μs period); generates interrupt or toggle SQW on expiry |
| Oscillator fail detection & flag | Monitors XI/XO node for 32.768 kHz oscillation; sets OFIE flag and asserts IRQ/FT/OUT if stopped >1 sec |
| Battery low warning | Dedicated BLF bit set when VBAT drops below 2.0 V; enables graceful shutdown or alert before RTC halt |
Applications
| Industrial Data Logger | Smart Energy Meter |
|---|---|
|
Use Scenario: Records sensor readings with precise UTC timestamps during grid outages using local battery power. IC Role / Device Role / Timing Role: Primary RTC maintaining calendar/time-of-day and generating alarm-triggered log entries. Use Value: 365 nA battery current enables >12-year CR2032 life; VSO = 2.32 V ensures timestamp continuity before meter MCU loses power. |
Use Scenario: Tracks energy consumption intervals and initiates tariff switching at midnight using accurate calendar functions. IC Role / Device Role / Timing Role: Timekeeping engine synchronizing billing cycles and validating firmware update windows. Use Value: ±5 ppm accuracy limits cumulative error to <1.5 sec/month; BCD calendar auto-corrects for leap years and variable month lengths. |
| Medical Infusion Pump | Building Automation Controller |
|
Use Scenario: Logs therapy start/stop times and alarms for dose verification, retaining history across AC power loss. IC Role / Device Role / Timing Role: Backup-timestamping module storing audit trail in 7-byte SRAM during main power interruption. Use Value: Battery-backed SRAM preserves last-dose timestamp and error codes; IRQ/FT/OUT wakes MCU on alarm for immediate response. |
Use Scenario: Schedules HVAC setpoint changes and lighting control based on weekday/holiday calendars. IC Role / Device Role / Timing Role: Central time source coordinating distributed nodes via SPI-bus-connected microcontrollers. Use Value: Programmable square wave (32.768 kHz) serves as low-jitter clock for local ADC sampling; dual alarms trigger maintenance alerts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar real-time clock applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS3231M | TCXO-based (±2 ppm), higher 1.5 μA battery current, I²C-only interface | Requires I²C bus; better accuracy but incompatible SPI design; no user SRAM | Select DS3231M only if system already uses I²C and demands <2 ppm accuracy; reject if SPI is mandatory or SRAM needed. |
| M41T81SMY6E | I²C interface, no analog calibration, 850 nA battery current, same SOX18/QFN16 packaging | Lacks programmable load capacitance and digital calibration; limited to ±20 ppm post-reflow accuracy | Choose M41T81SMY6E for cost-sensitive designs where ±20 ppm suffices and I²C is available; avoid when fine-grained drift compensation is required. |
Compared with DS3231M and M41T81SMY6E, the M41T93ZMY6E uniquely combines SPI compatibility, ultra-low 365 nA battery draw, dual calibration methods, and 7-byte SRAM-making it optimal for SPI-based industrial controllers needing long-term autonomous timekeeping with field-adjustable accuracy.
Availability
M41T93ZMY6E is available at Aetrix Electronics and suitable for industrial data loggers, smart energy meters, medical infusion pumps, and building automation controllers requiring stable component supply across extended product lifecycles.
Supply support for M41T93ZMY6E 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, specializing in microcontrollers, power management, and precision analog ICs for industrial, automotive, and consumer markets.
The M41T93 belongs to ST's real-time clock portfolio designed for robust, battery-backed timekeeping in harsh environments-emphasizing low-power operation, switchover reliability, and field-calibration capability for long-lifecycle equipment.
FAQ
What is the minimum VCC voltage that maintains full RTC functionality before switchover?
The M41T93ZMY6E operates fully down to 2.38 V. Below this, the device enters brown-out detection; at VCC = 2.32 V (VSO), it automatically switches to VBAT and halts SPI communication while preserving timekeeping. No register corruption occurs during this transition, and all calendar counters continue incrementing from battery power.
How does the analog calibration register adjust oscillator accuracy?
The analog calibration register (address 0x13) controls internal load capacitance from 0 to 12.5 pF in 0.5 pF steps. This fine-tunes crystal pull, compensating for board-level parasitics and crystal tolerance. Combined with digital calibration (±127 ppm), it enables sub-ppm residual drift correction-verified via temperature sweep testing per Figure 12 in the datasheet.
Can the second alarm be used simultaneously with the watchdog timer?
Yes. Alarm 2 and the watchdog timer operate independently using separate register sets (addresses 0x15–0x19 and 0x0A). Both can assert IRQ/FT/OUT concurrently-the interrupt priority is fixed per Table 11 (VCC mode) and Table 12 (backup mode), with watchdog having higher precedence than Alarm 2 during main power operation.
Is the 7-byte SRAM retained during VCC power cycling without battery?
No. The 7-byte SRAM is battery-backed only. If VBAT is unconnected (tied to VSS) and VCC drops below VSO, SRAM contents are lost within milliseconds. Retention requires a functional battery or supercapacitor on VBAT; the datasheet specifies 10-year data retention at +25°C with CR2032 and typical leakage.
M41T93ZMY6E 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:
- 2.38V ~ 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
M41T93ZMY6E FAQ
1.How can I place an order for M41T93ZMY6E through Aetrix?
Please submit a Request for Quotation (RFQ) for M41T93ZMY6E 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 M41T93ZMY6E reliable?
The price and inventory of M41T93ZMY6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M41T93ZMY6E is usually 5 days.
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4.How is shipping managed for M41T93ZMY6E?
M41T93ZMY6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M41T93ZMY6E 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 M41T93ZMY6E?
For technical support, including M41T93ZMY6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M41T93ZMY6E requirements.
6.How does Aetrix verify that M41T93ZMY6E is sourced from the original manufacturer or authorized distributors?
All M41T93ZMY6E 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 M41T93ZMY6E meets industry standards.
7.What is the process for return or replacement of M41T93ZMY6E?
All M41T93ZMY6E units undergo pre-shipment inspection (PSI). If there is an issue with M41T93ZMY6E, 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 M41T93ZMY6E part is unused and in its original packaging.
Return procedure for M41T93ZMY6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
M41T93ZMY6E Tags
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MCP7940N-I/SN
Microchip Technology
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MCP7940MT-I/MNY
Microchip Technology
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PCF85063ATL/1,118
NXP USA Inc.
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MCP7940NT-I/SN
Microchip Technology
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MCP7940NT-I/MS
Microchip Technology
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MCP7940N-I/MS
Microchip Technology
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PCF85063AT/AY
NXP USA Inc.
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PCF85063TP/1Z
NXP Semiconductors
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PCF85063ATT/AJ
NXP USA Inc.
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MCP7940NT-E/SN
Microchip Technology
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MCP7940NT-I/MNY
Microchip Technology
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MCP79400T-I/SN
Microchip Technology
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