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Renesas X1226S8Z
- Part No.:
- X1226S8Z
- Manufacturer:
- Renesas
- Category:
- Real Time Clocks
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
X1226S8Z.pdf
- Description:
- IC RTC CLK/CALENDAR I2C 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,853
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Product details
Overview
X1226S8Z from Intersil is a 4K-bit (512 × 8) real-time clock/calendar IC with integrated 2-wire™ (I²C-compatible) interface, dual non-volatile alarms, on-chip oscillator compensation, and 512-byte EEPROM. It operates from 2.7–5.5V, draws 1.25µA typical operating current, and maintains timekeeping down to 1.8V during battery backup. Used in utility meters, HVAC controllers, and network infrastructure for accurate timestamping and configuration storage.
For engineers reviewing the X1226S8Z datasheet, X1226S8Z pinout, X1226S8Z application, or X1226S8Z equivalent, this page delivers verified technical context, validated pin functions, confirmed EEPROM block-lock protection modes, oscillator trim capability (±30ppm digital + analog), and real-world alarm use cases - all specific to the Pb-free 8-lead SOIC variant.
Technical Context
The X1226S8Z integrates a 32.768kHz crystal oscillator with fully on-die compensation circuitry-including a 64-position digitally controlled trim capacitor and six analog frequency adjustment settings-enabling ±30ppm digital tuning and up to ±146ppm total compensation when combined with analog ATR register control. Its RTC core maintains BCD-encoded time/date registers with automatic leap-year correction through 2099.
It implements two independent, non-volatile alarm registers (Alarm 0 and Alarm 1), each configurable to trigger on second, minute, hour, day-of-week, date, or month match, with repeat mode enabled via IM bit. The PHZ/IRQ pin serves as either open-drain interrupt output (active-low) or software-selectable frequency output (1Hz/4096Hz/32.768kHz), mutually exclusive with IRQ functionality.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| RTC Accuracy | ±30ppm after digital trim; full ±146ppm compensation range with analog ATR register - enables sub-minute/month drift without external calibration. |
| Interface | I²C-compatible 2-wire™ at 400kHz - supports standard microcontroller I²C peripherals without protocol translation. |
| EEPROM Size | 512 × 8 bits (4Kb), with 64-byte page write and eight BlockLock™ protection modes - allows secure storage of critical calibration data and user settings. |
| Alarm Capability | Dual non-volatile alarms with maskable fields (second to month) and repeat mode - enables periodic wake-up or event notification without host polling overhead. |
| Power Supply Range | 2.7–5.5V VCC; RTC remains functional down to 1.8V on VBACK - ensures uninterrupted timekeeping during brownout or main power loss. |
| Operating Current | 1.25µA typical (VCC = 3.3V, T = 25°C) - minimizes battery drain in long-life backup applications. |
| Package | 8-lead SOIC (150 mil), Pb-free plus anneal (RoHS compliant) - compatible with standard reflow profiles and legacy SOIC footprints. |
Pinout & Package
Package: 8-lead SOIC (150 mil), MDP0027 footprint, RoHS-compliant Pb-free plus anneal finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| X1 | Oscillator input | Input to on-chip inverting amplifier; connects to one terminal of external 32.768kHz crystal - requires short trace and ground plane for stability. |
| X2 | Oscillator output | Output of on-chip inverting amplifier; connects to other crystal terminal - completes integrated Pierce oscillator loop. |
| PHZ/IRQ | Programmable frequency/interrupt output | Open-drain output; software-selectable between 1Hz/4096Hz/32.768kHz frequency or active-low alarm interrupt - function selected via FO1/FO0 bits. |
| VSS | Ground reference | Primary digital ground return path; must be connected to system ground plane for noise immunity and RTC accuracy. |
| SDA | Serial data line | Bidirectional, open-drain I²C data line requiring external pull-up; slope-controlled fall time optimized for 400kHz operation. |
| SCL | Serial clock line | Input-only I²C clock line; always-active input buffer synchronizes all read/write transfers with master clock. |
| VBACK | Backup supply input | Accepts battery or supercap; powers RTC and SRAM when VCC < VBACK – 0.2V - enables seamless switchover during main power failure. |
| VCC | Main supply voltage | Primary power source (2.7–5.5V); powers logic, EEPROM, and interface - powers entire device except RTC core in standby. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip oscillator compensation | Combines 64-position digital trim capacitor and 6-bit analog trim (ATR) to adjust load capacitance from 3.25pF to 18.75pF - eliminates external trim caps and reduces BOM count by ≥2 components. |
| Dual non-volatile alarms | Each alarm stores full time/date match criteria (second to month) and retains settings across power cycles - enables scheduled events like daily firmware checks or weekly log dumps without host memory retention. |
| BlockLock™ EEPROM protection | Eight programmable lock modes (e.g., full array, upper 1/4, first 8 pages) - prevents accidental overwrites of calibration constants while allowing field-updatable user data in unlocked regions. |
| Low-power RTC operation | 1.25µA typical current draw at 3.3V with oscillator running - extends coin-cell battery life beyond 10 years in metering applications. |
| Temperature-compensated timekeeping | Supports crystal temperature drift mitigation via digital + analog trim - achieves stable ±30ppm accuracy across 0°C to 70°C industrial range without external sensors. |
Applications
| Utility Metering | HVAC Control Systems |
|---|---|
|
Use Scenario: Time-stamping energy consumption data every 15 minutes for billing and grid analytics. IC Role / Device Role / Timing Role: Primary RTC providing synchronized, tamper-resistant timestamps with battery-backed continuity during mains outage. Use Value: Ensures regulatory compliance with ANSI C12.1 and IEC 62056 standards via guaranteed 100-year data retention and 100,000 EEPROM write cycles. |
Use Scenario: Scheduling fan speed changes, filter alerts, and seasonal mode transitions based on local time and day-of-week. IC Role / Device Role / Timing Role: Calendar-aware scheduler generating hardware interrupts (via PHZ/IRQ) to wake MCU from deep sleep at precise intervals. Use Value: Reduces average system power by >70% versus continuous polling, leveraging dual alarms for overlapping weekly/daily triggers. |
| Network Infrastructure | Industrial Test Equipment |
|
Use Scenario: Timestamping SNMP trap logs and firmware update records in routers and switches. IC Role / Device Role / Timing Role: Secure time source storing audit trails in protected EEPROM blocks, isolated from main processor firmware updates. Use Value: Prevents log corruption during field upgrades using BlockLock™ to lock timestamp registers while permitting dynamic log buffer writes. |
Use Scenario: Calibrating multimeters and oscilloscopes with date-stamped calibration coefficients and expiration tracking. IC Role / Device Role / Timing Role: Trusted time anchor and non-volatile configuration store - retains calibration validity dates and sensor offset values across power cycles. Use Value: Meets ISO/IEC 17025 traceability requirements via 100-year data retention and deterministic RTC fail detection (RTCF bit). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar real-time clock/calendar applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS1337+T&R | Lacks integrated EEPROM; no on-chip oscillator compensation; only single alarm; I²C max 100kHz. | Requires external trim cap and separate EEPROM for configuration storage - increases board area and component count. | Select if cost sensitivity outweighs accuracy and integration needs; verify external crystal layout meets DS1337's tighter load capacitance tolerance. |
| PCF8563T | No EEPROM; no oscillator compensation; only one alarm; lower accuracy (±2ppm typ. crystal + ±10ppm temp drift). | Relies entirely on external crystal quality; no provision for field recalibration - unsuitable for long-term unattended deployments. | Choose for simple timekeeping where ±2 minutes/month drift is acceptable and external memory is already present. |
Compared with DS1337+T&R and PCF8563T, the X1226S8Z delivers superior integration (EEPROM + dual alarms + compensation), higher accuracy headroom, and lower system-level BOM cost - making it optimal for applications demanding autonomous, long-life, tamper-resilient timekeeping.
Availability
X1226S8Z is available at Aetrix Electronics and suitable for utility metering, HVAC control systems, and network infrastructure requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for X1226S8Z 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
Intersil (now part of Renesas Electronics) is a semiconductor company specializing in precision analog, power management, and timing solutions for industrial, communications, and computing markets.
The X1226S8Z belongs to Intersil's RTC family designed for high-accuracy, low-power, battery-backed timekeeping in mission-critical embedded systems - emphasizing integration, reliability, and ease of crystal calibration.
FAQ
What is the backup voltage range supported by the X1226S8Z?
The X1226S8Z supports VBACK from 1.3V to 5.5V. When VCC drops below VBACK – 0.2V, the internal power switch automatically routes VBACK to sustain RTC and SRAM operation. The clock portion remains fully functional down to 1.8V on VBACK, ensuring time continuity during extended brownouts - a key feature confirmed in the FN8098 datasheet Section 5.
Does the X1226S8Z require an external crystal, and what are the recommended specifications?
Yes, the X1226S8Z requires an external 32.768kHz quartz crystal connected between X1 and X2 pins. The datasheet explicitly recommends the Citizen CFS206-32.768KDZF (12.5pF load, ±20ppm tolerance). Its on-chip compensation circuitry is calibrated for this part, enabling full ±146ppm trim range - critical for achieving the specified ±30ppm post-trim accuracy.
How many bytes of EEPROM does the X1226S8Z provide, and how is write protection implemented?
The X1226S8Z provides 512 bytes (4Kb) of EEPROM organized as 512 × 8 bits. Write protection is implemented via three Block Protect (BP2–BP0) bits, enabling eight distinct lock configurations - including full-array lock, upper 1/4 lock, and first-page lock. This BlockLock™ mechanism prevents accidental writes to critical calibration or configuration data while allowing unrestricted access to user-defined regions.
Can both alarms on the X1226S8Z operate simultaneously, and what interrupt modes are supported?
Yes, Alarm 0 and Alarm 1 operate independently and can trigger concurrently. Each alarm supports both polled status (AL0/AL1 bits in Status Register) and hardware interrupt output via the PHZ/IRQ pin. The IM bit enables pulse interrupt mode, generating periodic pulses at the configured alarm interval - verified in the Alarm Registers section (Page 7) and INT register description (Page 8) of FN8098 Rev 3.00.
What is the maximum I²C bus speed supported by the X1226S8Z?
The X1226S8Z supports standard-mode I²C up to 400kHz, as confirmed in the FEATURES section (Page 1) and PIN DESCRIPTIONS (Page 4). Its SDA output uses slope-controlled pull-down to meet rise/fall time requirements at this speed, and the SCL input buffer remains always active - ensuring reliable communication with common microcontroller I²C peripherals without additional level-shifting or timing constraints.
X1226S8Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, Leap Year
- Memory Size:
- -
- Time Format:
- HH:MM:SS (12/24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- I2C, 2-Wire Serial
- Voltage - Supply:
- 2.7V ~ 5.5V
- Voltage - Supply, Battery:
- 1.8V ~ 5.5V
- Current - Timekeeping (Max):
- 10µA ~ 20µA @ 2.7V ~ 5V
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-SOIC
X1226S8Z FAQ
1.How can I place an order for X1226S8Z through Aetrix?
Please submit a Request for Quotation (RFQ) for X1226S8Z 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 X1226S8Z reliable?
The price and inventory of X1226S8Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for X1226S8Z is usually 5 days.
3.What payment methods are accepted for X1226S8Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for X1226S8Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for X1226S8Z?
X1226S8Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your X1226S8Z 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 X1226S8Z?
For technical support, including X1226S8Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your X1226S8Z requirements.
6.How does Aetrix verify that X1226S8Z is sourced from the original manufacturer or authorized distributors?
All X1226S8Z 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 X1226S8Z meets industry standards.
7.What is the process for return or replacement of X1226S8Z?
All X1226S8Z units undergo pre-shipment inspection (PSI). If there is an issue with X1226S8Z, 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 X1226S8Z part is unused and in its original packaging.
Return procedure for X1226S8Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
X1226S8Z Tags
-
MCP7940N-I/SN
Microchip Technology
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MCP7940MT-I/MNY
Microchip Technology
-
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
-
PCF85063AT/AY
NXP USA Inc.
-
PCF85063TP/1Z
NXP Semiconductors
-
PCF85063ATT/AJ
NXP USA Inc.
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MCP7940NT-E/SN
Microchip Technology
-
MCP7940NT-I/MNY
Microchip Technology
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MCP79400T-I/SN
Microchip Technology
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