DS3231M+ - ±5 ppm I2C Real-Time Clock | Maxim Integrated
MPN： DS3231M+ ✓ 啟用中DS3231M+ 概覽
A real-time clock is a clock-and-timing IC that preserves calendar time independently of a system processor. The RTC category sits within integrated timing circuits, where an oscillator and digital timekeeping logic maintain a reference even when the main system is unpowered. The DS3231M+ uses a MEMS resonator rather than a conventional quartz crystal, reducing external components while supporting stable long-term timekeeping. Its integrated temperature compensation is designed to maintain accuracy across changing ambient conditions.
The device supports a 400 kHz I2C interface, two programmable alarms, and a square-wave output that can be used for periodic interrupts or clocking-related functions. Register access and real-time data use the familiar BCD date and time format. The DS3231M+ is specified for a 16-pin, 7.50 mm-wide SOIC package, making it suitable for compact embedded boards that use a common 16-pin land pattern.
Its internal MEMS resonator eliminates the need for an external crystal, while the integrated digital compensation removes external calibration components. The result is a compact timebase with fewer external components than a discrete crystal-and-capacitor implementation. The device can operate directly from a 3.3 V or 5 V system supply while preserving the calendar through a backup battery.
Typical uses include industrial data loggers, environmental monitors, instrumentation, embedded control systems, network appliances, and consumer electronics. It is especially useful when the host microcontroller can be reset or power-cycled but the system must retain wall-clock time. Its I2C interface also allows firmware to obtain time without burdening the host with timing logic.
Designers should use suitable pull-up resistors on the I2C bus, connect the backup battery to the designated supply input, and review the oscillator-startup and power-loss behavior in the manufacturer datasheet. PCB placement should keep I2C routing away from high-current switching nodes and noisy sources. For timing-critical systems, validate the complete power, layout, and firmware configuration rather than relying only on nominal RTC accuracy.
直接替換替代品，適用於 DS3231M+ — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： DS3231M+ （相同外形與佔位） — 差異在於 Package, Calendar Function, Device Type, RoHS Status, Mounting Type.
DS3231SN#
✅ 直接替換聯絡詢價
查看資料表 →DS3231MZ+
✅ 直接替換聯絡詢價
查看資料表 →DS3231M TRL
✅ 直接替換📋 參考替代品（不在目錄中）
DS3231M+ 規格
| Product Type | I2C real-time clock and calendar IC |
| Initial Accuracy | ±5 ppm |
| 工作電源電壓 | 2.3 V to 5.5 V |
| I2C Bus Speed | 400 kHz |
| Timekeeping Format | Hours, minutes, seconds, day, date, month, and year in BCD |
| Oscillator Technology | Integrated MEMS resonator |
| Temperature Compensation | Integrated digital temperature compensation |
| Backup Battery Support | Yes |
| Alarm Functions | 2 programmable alarms |
| Square-Wave Output | Programmable |
| 介面 | I2C, 2-wire serial |
| 封裝 | 16-pin SOIC, 7.50 mm width |
| 安裝類型 | Surface mount |
DS3231M+ 16-pin soic, 7.50 mm width 腳位配置指南
DS3231M+（16-pin soic, 7.50 mm width 封裝）的腳位配置。 腳位編號、功能與連接圖定義於製造商資料手冊中。請參閱該手冊以取得確切的封裝尺寸與焊接指引。
無詳細腳位定義資料： DS3231M+.
請參閱 資料表 以查看完整腳位配置。
典型應用
DS3231M+ 適用於 6 應用s: Industrial Environmental Data Loggers, Precision Test and Measurement Equipment, IoT Gateways and Network Appliances, Medical and Laboratory Monitoring Systems, Battery-Powered Portable Instruments, Access Control and Security Timing Systems.
Industrial Environmental Data Loggers
The DS3231M+ fits environmental monitoring systems that must timestamp temperature, humidity, air-quality, or vibration samples across long operating intervals. Its ±5 ppm initial accuracy and integrated temperature compensation provide a more consistent time reference than many simple host-clock implementations, while two alarms can trigger periodic sampling or synchronized measurements. The 400 kHz I2C interface permits the logger’s microcontroller to read the calendar efficiently. Because the device continues from a coin-cell backup source, recorded timestamps remain available after a logger reset or main-power interruption. Designers should still validate start-up behavior, battery life, and the complete operating-temperature grade in the intended enclosure.
推薦
Precision Test and Measurement Equipment
The DS3231M+ is useful in test and measurement instruments where event logs, calibration records, or multi-instrument captures must retain accurate timestamps. The integrated MEMS resonator avoids a discrete crystal and its associated load capacitors, reducing assembly parts while retaining ±5 ppm initial accuracy. Its programmable alarms and square-wave output can support periodic capture triggers or status timing, and the I2C bus allows a controller such as an STM32F446VCT6TR to retrieve time without burdening the host. In synchronized systems, engineers should compare clock skew, trigger latency, and timestamp semantics rather than treating the RTC accuracy value as a complete measurement-timing specification.
推薦
IoT Gateways and Network Appliances
The DS3231M+ fits IoT gateways and network appliances that need a persistent wall-clock reference for event logs, scheduled actions, certificate workflows, or maintenance records. Its 2.3 V to 5.5 V operating range supports common embedded supply rails, and the 400 kHz I2C interface works efficiently with a host microcontroller such as STM32F103C8T7. The battery input helps preserve time during brief supply interruptions, making recovery behavior more predictable. For connected products, the I2C traces should be kept away from Ethernet magnetics and high-energy switching nodes, while the backup-battery chemistry must match the device requirements and expected discharge profile.
推薦
Medical and Laboratory Monitoring Systems
The DS3231M+ can support timestamped records in laboratory instruments and connected medical-adjacent monitoring equipment where event chronology must survive a controller reset. The ±5 ppm clock and integrated temperature compensation are valuable for maintaining consistent timestamps across ambient changes, while two alarms can support scheduled measurements or reminders. A controller such as STM32F411RET6TR can read the RTC over I2C and synchronize samples. Compliance depends on the complete medical system rather than the RTC alone, so engineers should confirm the applicable temperature range, battery handling, alarm behavior, and risk-control requirements before deployment in a regulated environment.
推薦
Battery-Powered Portable Instruments
The DS3231M+ is appropriate for portable instruments that must retain date and time while their main power is switched off. The integrated MEMS resonator reduces the external crystal component count, which is helpful in compact battery-powered equipment, and the backup-battery input allows continued calendar operation independently of the host supply. A low-power MCU such as STM32L-family devices or STM8L001J3M3 can poll the 400 kHz I2C interface only when required. Designers should select a suitable primary-cell or rechargeable backup arrangement, calculate expected backup consumption, and account for the time required for the MEMS oscillator to become valid after power restoration.
推薦
Access Control and Security Timing Systems
The DS3231M+ can support access-control, audit, and security-event systems that require trusted timestamps even after a controller reboot. Its battery-backed timekeeping preserves the calendar during power interruptions, while its alarms and square-wave output can support scheduled access windows or periodic audit tasks. An STM32F072RBT6TR or similar MCU can use the I2C interface to coordinate records with credential events. For security-sensitive installations, designers should add protocol-level authentication and secure time distribution where required, protect the backup source from physical access, and verify alarm polarity and firmware handling for each peripheral.
推薦
推薦產品摘要
工程參考資料，適用於 DS3231M+ — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | DS3231SN# | DS3231M | DS3231M TRL |
|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 16-pin SOIC | 16-pin SOIC | 16-pin SOIC | 16-pin WSOIC |
| RTC Function | Clock/calendar | Clock/calendar | Clock/calendar | Alarm clock/calendar |
| Interface | I2C, 2-wire serial | I2C, 2-wire serial | I2C, 2-wire serial | I2C, 2-wire serial |
主要差異化特點
- Integrated MEMS timebase reduces external oscillator components (對比DS3231SN#)
- Broad operating supply range supports common embedded rails (對比DS3231SN#)
- MEMS-based design combines accuracy with temperature compensation (對比DS3231M TRL)
設計說明
Place the DS3231M+ close to its backup source and route the I2C lines as short, continuous traces away from switching nodes, inductors, and high-current return paths. Use pull-up resistors that support the intended 400 kHz bus while keeping the logic-high voltage compatible with the host. The verified data does not provide the complete pinout, so the exact PCB land pattern must be checked against the official manufacturer datasheet before release.
Separate the main supply and backup-battery paths as directed by the manufacturer datasheet and provide local decoupling close to the device. Estimate backup-cell life from the RTC's backup current, battery capacity, temperature, and expected main-off duration rather than assuming indefinite operation. The verified sources establish battery-backed operation but do not provide a numeric backup-current figure, so that calculation must use the manufacturer specification.
Do not treat a shared 16-SOIC outline as proof of drop-in compatibility. The verified comparison data indicates that DS3231SN# uses a crystal-based 3.3 V design and may differ in I2C addressing or configuration, while DS3231M TRL is identified as a distinct alarm-RTC ordering code. Before substitution, verify every pin function, supply limit, I2C address, alarm behavior, square-wave output, battery input, and register compatibility.
Keep the oscillator and backup-battery area away from high-energy switching circuitry and maintain a quiet ground reference for the RTC. If the board contains isolated or switching power converters, compare clock accuracy at the system operating limits because temperature gradients and supply ripple can affect real-world performance. Use the manufacturer's application guidance and measure timekeeping after cold starts rather than relying only on the ±5 ppm initial-accuracy specification.
合規資訊
The supplied verified snippets and comparison results do not provide authoritative compliance values for the DS3231M+. AEC-Q100 is not applicable because this is an RTC rather than an automotive-qualified component. Verify RoHS, REACH, lead-free, halogen-free, and conflict-minerals declarations against the current manufacturer product documentation or supplier declarations.
