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Analog Devices Inc./Maxim Integrated DS1629S
- Part No.:
- DS1629S
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Thermal Management
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
DS1629S.pdf
- Description:
- IC THERM/RTC/CALENDAR DIG 8-SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,730
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Product details
Overview
DS1629S from Maxim Integrated (now Analog Devices) is a 2-wire digital thermometer and real-time clock IC integrating temperature sensing, calendar/timekeeping, alarm generation, and 32-byte SRAM in an 8-pin SO package. It delivers ±2.0°C typical temperature accuracy across –55°C to +125°C, supports 9-bit resolution with expandable high-resolution mode, and operates from 2.2V to 5.5V - enabling use in battery-powered thermal monitoring and time-stamped data logging systems.
For engineers reviewing the DS1629S datasheet, DS1629S pinout, DS1629S application, or DS1629S equivalent, this device serves as a self-contained, crystal-referenced temperature/time sensor with programmable thermal/time alarms, open-drain ALRM output, and I²C-compatible 2-wire interface - critical for embedded thermal management, environmental logging, and low-power RTC subsystems.
Technical Context
The DS1629S implements a bandgap-based delta-sigma ADC for direct temperature-to-digital conversion and a BCD-coded RTC with leap-year compensation through 2100, driven by an external 32.768kHz crystal connected between X1 and X2. Its oscillator divider and buffered OSC output support microcontroller clocking at selectable frequencies (fO, fO/4, fO/8, or disabled).
Alarm logic is fully configurable via nonvolatile configuration bits: A0/A1 select thermal-only, time-only, either-or, or disabled alarm activation; POL sets ALRM polarity (active-low default); and TAF/CAF flags provide volatile status reporting. Temperature and clock registers are accessed via dedicated 2-wire command protocols (e.g., AAh, C0h, A1h), with EEPROM-backed TH/TL registers supporting 2K write cycles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Temperature Range | –55°C to +125°C; enables operation in industrial, automotive, and extended-environment applications without external conditioning. |
| Thermometer Accuracy | ±2.0°C (typ); provides reliable thermal threshold detection for safety-critical overtemperature protection. |
| Resolution | 9-bit (0.5°C LSB); supports high-precision measurement with optional software-enhanced resolution using COUNT_REMAIN/COUNT_PER_C. |
| RTC Format | BCD-coded seconds/minutes/hours/day/date/month/year with automatic month-end and leap-year correction through 2100. |
| Interface | 2-wire (I²C-compatible) serial bus; supports up to 400kHz clock rate and multi-device addressing with fixed 1001xxx slave address. |
| Power Supply | 2.2V to 5.5V; allows direct integration into 3.3V and 5V systems and long-life battery operation (e.g., coin cell). |
| SRAM | 32 bytes of user-accessible RAM; usable for time-stamped temperature histograms, calibration offsets, or system state storage. |
| Alarm Output | Dedicated open-drain ALRM pin; configurable for active-high or active-low assertion on thermal exceedance, clock match, or either event. |
Pinout & Package
DS1629S is housed in an 8-pin SOIC (150-mil) RoHS-compliant package with gull-wing leads and standard JEDEC MS-012AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SDA | 2-wire serial data I/O | Open-drain bidirectional line for reading/writing registers; requires external pull-up resistor (typically 4.7kΩ). |
| 2 - SCL | 2-wire serial clock input | Master-generated clock signal; maximum frequency 400kHz; synchronizes all register transfers. |
| 3 - ALRM | Configurable alarm output | Open-drain output asserted when temperature ≥ TH or clock matches alarm register; polarity set by POL bit. |
| 4 - GND | Ground reference | Primary return path for VDD, internal circuitry, and crystal oscillator; must be low-impedance connection. |
| 5 - X2 | Crystal feedback output | Drives crystal's feedback terminal; forms Pierce oscillator with internal inverter and external 32.768kHz tuning fork crystal. |
| 6 - X1 | Crystal input | Connects to crystal's input terminal; completes oscillator loop with X2; no external load capacitors required. |
| 7 - OSC | Buffered oscillator output | Open-drain output providing divided crystal frequency (fO, fO/4, fO/8, or disabled) for MCU clock sourcing. |
| 8 - VDD | Power supply input | Accepts 2.2V–5.5V; powers RTC, thermometer, SRAM, and interface; EEPROM writes require ≥2.7V. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated RTC + Thermometer | Single-chip solution eliminates separate timekeeping and temperature ICs, reducing BOM count and PCB area in space-constrained designs. |
| Programmable Alarm Logic | Four independent alarm modes (thermal only, time only, either, disabled) with latched and non-latched status flags (TAF/CAF, TAL/CAL) enable flexible event-driven system responses. |
| Factory-Calibrated Sensor | No external components needed for temperature measurement; delta-sigma ADC and bandgap reference ensure stable ±2.0°C accuracy across full range. |
| Nonvolatile TH/TL Registers | EEPROM-backed high/low temperature thresholds (2K write endurance) retain alarm settings across power cycles without backup power. |
| Configurable Oscillator Output | OSC pin delivers selectable frequencies (fO, fO/4, fO/8) or can be disabled - allowing precise clock sourcing for companion MCUs while minimizing power draw. |
| Low-Voltage Operation | Functional down to 2.2V enables direct use with single-cell Li-ion or alkaline batteries, extending runtime in portable thermal loggers. |
Applications
| Industrial Data Logger | PCB Thermal Monitor |
|---|---|
|
Use Scenario: Standalone battery-powered logger records ambient temperature and timestamps each reading every 10 minutes for 30 days. IC Role / Device Role / Timing Role: DS1629S acts as both temperature sensor and timebase - performing autonomous conversions and maintaining accurate calendar time using its internal RTC and 32.768kHz crystal. Use Value: Eliminates need for external RTC or microcontroller-based timing, reducing power consumption and firmware complexity while ensuring traceable, ISO-compliant timestamping. |
Use Scenario: Real-time thermal supervision of FPGA or power supply on a server motherboard, triggering fan control or shutdown if local die temperature exceeds 95°C. IC Role / Device Role / Timing Role: DS1629S functions as a local thermal watchdog with programmable TH/TL hysteresis and immediate ALRM assertion - independent of host processor activity. Use Value: Provides fail-safe, hardware-level overtemperature response even during host reset or firmware hang, improving system reliability. |
| Smart Thermostat Node | Medical Equipment Clock/Temp Module |
|
Use Scenario: Wireless HVAC sensor node measures room temperature and schedules heating cycles based on time-of-day and day-of-week settings. IC Role / Device Role / Timing Role: DS1629S supplies calibrated temperature readings and drives scheduled events via its clock alarm - synchronized to local time zone with leap-year-aware calendar. Use Value: Enables deterministic, low-power scheduling without host CPU involvement, extending battery life in battery-operated IoT nodes. |
Use Scenario: Portable diagnostic device logs patient temperature with precise timestamps during clinical trials, requiring FDA-grade time traceability and thermal accuracy. IC Role / Device Role / Timing Role: DS1629S serves as certified time source and primary temperature transducer - storing calibrated offset values in its 32-byte SRAM for post-processing correction. Use Value: Meets IEC 62304 Class B requirements for time-stamped medical data by combining validated RTC functionality and factory-traceable temperature calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar digital thermometer and RTC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS3231M | Higher RTC accuracy (±2ppm vs. ±20ppm), integrated TCXO, no built-in thermometer; requires external temp sensor. | Better suited for precision timekeeping where temperature sensing is secondary or handled separately. | Choose DS3231M when nanosecond-level time stability is critical and thermal monitoring is delegated to another IC. |
| MAX31875 | Dedicated ±0.25°C accuracy digital thermometer only; no RTC, no SRAM, no alarm output; I²C interface only. | Optimized for high-accuracy thermal sensing without timekeeping - lower cost and power than combined-function devices. | Choose MAX31875 when only temperature measurement is required and system already includes a separate RTC or time source. |
Compared with DS1629S, DS3231M offers superior timekeeping but lacks integrated temperature sensing, while MAX31875 delivers higher thermal accuracy but omits clock/calendar, SRAM, and alarm logic - making DS1629S uniquely balanced for compact, dual-function thermal-time subsystems.
Availability
DS1629S is available at Aetrix Electronics and suitable for industrial data loggers, PCB thermal monitors, smart thermostat nodes, and medical equipment clock/temp modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for DS1629S 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
Analog Devices (formerly Maxim Integrated) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.
The DS1629S belongs to Maxim's legacy precision timing and sensor family, designed specifically for embedded systems needing co-located, low-power temperature measurement and real-time clock functionality in minimal board space.
FAQ
What is the operating voltage range for the DS1629S?
The DS1629S operates from 2.2V to 5.5V for RTC, SRAM, and 2-wire communication functions. However, reliable EEPROM writes (e.g., to TH/TL registers) and temperature conversions require VDD ≥ 2.7V. This dual-threshold design ensures robust timekeeping and memory retention at ultra-low voltages while preserving write integrity at higher rails.
Does the DS1629S require external components to function as a thermometer?
No - the DS1629S contains a factory-calibrated bandgap temperature sensor and delta-sigma ADC, requiring no external resistors, capacitors, or op-amps. Only an external 32.768kHz crystal (between X1 and X2) is mandatory for RTC operation; the thermometer functions independently once powered.
How does the DS1629S handle leap years and month-end date adjustments?
The DS1629S RTC automatically adjusts the date at month end - including February in leap years - through the year 2100. Its BCD-coded calendar logic evaluates year divisibility rules in hardware, eliminating firmware overhead for date rollover handling in host microcontrollers.
Can the DS1629S generate alarms based on both time and temperature simultaneously?
Yes - the DS1629S supports "either thermal or time" alarm mode (A0=A1=1). In this configuration, ALRM asserts if temperature ≥ TH OR clock matches alarm register. Status flags TAF and CAF allow the host to determine which condition triggered the alarm, and ALRM remains active until both conditions clear.
What is the maximum I²C clock speed supported by the DS1629S?
The DS1629S supports standard-mode and fast-mode I²C operation up to 400kHz. Its 2-wire interface complies with I²C protocol timing requirements, including START/STOP conditions, ACK/NACK handshaking, and 9-bit transfer framing - enabling interoperability with common microcontrollers and I²C masters.
DS1629S Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Thermometer, Thermostat
- Sensor Type:
- Internal
- Sensing Temperature:
- -55°C ~ 125°C
- Accuracy:
- ±2°C(Max)
- Topology:
- ADC, Comparator, Oscillator, Register Bank
- Output Type:
- I2C/SMBus
- Output Alarm:
- Yes
- Output Fan:
- No
- Voltage - Supply:
- 2.7V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
DS1629S FAQ
1.How can I place an order for DS1629S through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1629S 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 DS1629S reliable?
The price and inventory of DS1629S are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1629S is usually 5 days.
3.What payment methods are accepted for DS1629S?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1629S transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1629S?
DS1629S orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1629S 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 DS1629S?
For technical support, including DS1629S datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1629S requirements.
6.How does Aetrix verify that DS1629S is sourced from the original manufacturer or authorized distributors?
All DS1629S 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 DS1629S meets industry standards.
7.What is the process for return or replacement of DS1629S?
All DS1629S units undergo pre-shipment inspection (PSI). If there is an issue with DS1629S, 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 DS1629S part is unused and in its original packaging.
Return procedure for DS1629S:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
DS1629S Tags
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EMC2101-ACZL-TR
Microchip Technology
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MCP9844T-BE/MNY
Microchip Technology
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EMC2101-R-ACZL-TR
Microchip Technology
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MCP98244T-BE/MNY
Microchip Technology
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TC670ECHTR
Microchip Technology
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SE98ATP,547
NXP Semiconductors
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AMC6821SDBQR
Texas Instruments
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MAX6604AATA+T
Analog Devices Inc./Maxim Integrated
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ADT7475ARQZ-REEL
onsemi
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MAX6643LBBAEE+
Analog Devices Inc./Maxim Integrated
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MAX6684ESA+T
Analog Devices Inc./Maxim Integrated
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MAX6639AEE+
Analog Devices Inc./Maxim Integrated
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