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Renesas ISL1221IUZ-T
- Part No.:
- ISL1221IUZ-T
- Manufacturer:
- Renesas
- Category:
- Real Time Clocks
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
ISL1221IUZ-T.pdf
- Description:
- IC RTC EVENT REC I2C 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,668
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Product details
Overview
ISL1221IUZ-T from Renesas (formerly Intersil) is a low-power real-time clock IC with integrated event detection, time stamping, 2-byte battery-backed SRAM, and 15-frequency FOUT output. It operates from 2.7V to 5.5V, consumes only 400nA on battery, and maintains calendar accuracy through 2099 with leap-year correction. Used in utility meters and security systems for tamper-proof time logging.
For engineers reviewing the ISL1221IUZ-T datasheet, ISL1221IUZ-T pinout, ISL1221IUZ-T application, or ISL1221IUZ-T equivalent, this page delivers verified technical context, I²C timing compliance at 400kHz, VBAT switchover thresholds (2.2V ±35mV), EVIN glitch filter options (0–31.25ms), and RTC accuracy compensation range (−94ppm to +140ppm).
Technical Context
The ISL1221IUZ-T implements a crystal-based RTC with separate time/calendar registers, automatic leap-year correction, and dual-mode operation (VDD or VBAT). Its event detection circuit supports configurable sampling rates (1/4Hz–2Hz) and selectable hysteresis (0/3.9/15.6/31.25ms) to minimize false triggers while enabling ultra-low-power monitoring.
It features an I²C interface compliant with 400kHz Fast Mode, open-drain SDA/SCL with 100nA leakage, and VIL/VIH thresholds referenced to VDD. The FOUT pin provides 15 programmable frequencies up to 32.768kHz, and IRQ/EVDET serves as a shared open-drain interrupt output for alarm or event detection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDD Range | 2.7V to 5.5V - supports wide-input industrial power rails without external regulation |
| VBAT Range | 1.8V to 5.5V - enables use with lithium coin cells (3V) or supercaps down to 1.8V standby |
| Battery Current | 400nA typical at VBAT = 3V - ensures >10-year backup life with standard CR2032 |
| I²C Speed | 400kHz - compatible with standard Fast Mode microcontrollers without clock stretching |
| FOUT Options | 15 selectable frequencies (1/32Hz to 32.768kHz) - supports system clock derivation or LED blink timing |
| RTC Accuracy | Compensation range −94ppm to +140ppm - corrects crystal drift across −40°C to +85°C |
| Event Sampling | Configurable 1/4Hz, 1Hz, or 2Hz - reduces average current by >99% vs. continuous monitoring |
Pinout & Package
ISL1221IUZ-T is housed in a Pb-free 10-lead MSOP package (3mm × 4.9mm, 0.5mm pitch), optimized for space-constrained metering and security applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| X1 | Clock Input | Inverting amplifier input for 32.768kHz crystal or external oscillator; supports direct drive |
| X2 | Clock Output | Inverting amplifier output; left open when X1 is driven externally |
| VBAT | Backup Supply | Intelligent switchover input; activates at VDD < 2.2V with 35mV hysteresis |
| GND | Ground Reference | Common return for all analog/digital circuits; requires low-impedance PCB connection |
| EVIN | Event Monitor Input | Detects high-level tamper signals; configurable pull-up (1µA) and glitch filtering |
| FOUT | Frequency Output | Open-drain output; 15 user-selectable frequencies; disabled during I²C activity |
| SDA | I²C Data Line | Bidirectional open-drain bus line; requires external pull-up; inactive in VBAT mode |
| SCL | I²C Clock Line | Input-only open-drain clock; gated off during battery backup to reduce leakage |
| IRQ/EVDET | Interrupt/Event Output | Shared open-drain output; asserts low on alarm match or valid EVIN event |
| VDD | Main Power Supply | Primary operating voltage; powers all logic, RTC, and I²C interface in normal mode |
Key Features
| Feature | Design Value |
|---|---|
| InterSeal™ Battery Saver | Zero initial battery drain until first VDD power-up - preserves shelf life of pre-batteried modules |
| Event Time Stamp | Stores full timestamp (sec/min/hr/date/month/year) in on-chip SRAM upon EVIN trigger - enables forensic audit trails |
| Low-Power Mode (LPMODE) | Reduces VDD supply current by ~600nA at 5V - eliminates VTRIP monitoring overhead for fixed VDD/VBAT systems |
| Crystal Compensation | Combined analog (−34ppm to +80ppm) and digital (±60ppm) trimming - achieves ±2ppm stability after calibration |
| Power-Fail Detection | RTCF bit indicates complete loss of both VDD and VBAT - allows firmware to flag unrecoverable time loss |
Applications
| Utility Metering | Security Tamper Monitoring |
|---|---|
Use Scenario: Time-stamping energy consumption data and detecting enclosure opening in smart electricity meters. IC Role / Device Role / Timing Role: Primary RTC and tamper-detection co-processor; maintains accurate billing time and logs intrusion events with timestamp. Use Value: Enables regulatory-compliant audit logs and prevents unauthorized meter access via hardware-enforced event capture. | Use Scenario: Monitoring panel doors or warranty seals in medical devices and test equipment. IC Role / Device Role / Timing Role: Standalone event logger with battery-backed memory; records first breach time even after main power loss. Use Value: Provides irrefutable, time-synchronized evidence of physical access without requiring host MCU intervention. |
| Network Infrastructure | POS & Fixed Wireless |
Use Scenario: Maintaining synchronized uptime clocks and detecting power interruptions in enterprise routers and switches. IC Role / Device Role / Timing Role: System timekeeper and power-fail indicator; supplies accurate wall-clock time and RTCF status to host processor. Use Value: Ensures consistent log timestamps across reboots and enables graceful failover based on clean vs. unclean shutdown detection. | Use Scenario: Tracking transaction timestamps and detecting enclosure breaches in point-of-sale terminals and broadband CPE. IC Role / Device Role / Timing Role: Dual-function RTC and security monitor; drives FOUT for display refresh and flags tamper events via IRQ/EVDET. Use Value: Meets PCI-DSS physical security requirements while reducing BOM count via integrated SRAM and event logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar real-time clock with event detection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS3231SN#T&R | Integrated TCXO (±2ppm), higher accuracy; no EVIN pin or event timestamp; 236 bytes SRAM | Lacks tamper detection and time-stamped event logging; better for precision timing, worse for security auditing | Select DS3231SN#T&R only if absolute time accuracy > event forensics is primary requirement |
| PCF2129AT | Integrated oscillator compensation; no FOUT pin; 16-byte SRAM; I²C timeout protection | Missing frequency output and dedicated event interrupt pin; weaker tamper response granularity | Choose PCF2129AT where compact footprint and I²C robustness outweigh need for FOUT flexibility and EVIN configurability |
Compared with DS3231SN#T&R and PCF2129AT, the ISL1221IUZ-T uniquely combines battery-backed event timestamping, 15-step FOUT, and InterSeal™ zero-initial-drain - making it optimal for cost-sensitive, security-critical metering and infrastructure applications requiring field-deployable longevity.
Availability
ISL1221IUZ-T is available at Aetrix Electronics and suitable for utility metering, network infrastructure, and security tamper monitoring requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for ISL1221IUZ-T 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
Renesas Electronics acquired Intersil in 2017 and continues its legacy of high-reliability analog and mixed-signal ICs for industrial, automotive, and communications markets.
The ISL1221IUZ-T belongs to Renesas' real-time clock product line, designed specifically for applications demanding secure, battery-backed timekeeping with integrated tamper detection and minimal power consumption.
FAQ
What is the minimum VBAT voltage required for ISL1221IUZ-T to retain RTC and SRAM functionality?
The ISL1221IUZ-T maintains full RTC and 2-byte SRAM operation down to 1.8V on VBAT. Below this threshold, timekeeping halts and SRAM contents may be lost. The device specifies VBAT = 1.8V to 5.5V as the functional backup range, with typical battery current of 400nA at 3V - enabling multi-year operation from common lithium coin cells. This behavior is confirmed in the DC Operating Characteristics table on page 3 of FN6316 Rev 1.00.
Does ISL1221IUZ-T support I²C communication while operating from VBAT?
No, the ISL1221IUZ-T disables its I²C interface (SDA and SCL buffers) during battery backup mode to minimize current draw. Only RTC, event detection, FOUT, and IRQ/EVDET remain active. Communication must occur during VDD-powered operation. This is explicitly stated in the Functional Description section (page 9): "The I2C bus is deactivated in battery backup mode to provide lower power." Therefore, host firmware must read/write registers and configure settings before VDD loss.
How does the ISL1221IUZ-T implement tamper detection with time stamping?
The ISL1221IUZ-T uses the EVIN pin to detect high-level events, storing full timestamp (seconds, minutes, hours, date, month, year) in on-chip registers upon trigger. When enabled, it sets the EVT bit, asserts IRQ/EVDET low, and optionally freezes RTC registers. Timestamp data persists in battery-backed memory and is accessible via I²C after power restoration. This capability is detailed in the General Description (page 7) and Event/Tamper Monitor section (page 9) of FN6316 Rev 1.00.
What are the exact VTRIP and hysteresis values for VDD-to-VBAT switchover in ISL1221IUZ-T?
The ISL1221IUZ-T transitions to VBAT mode when VDD falls below VTRIP = 2.2V ±35mV (typical 2.2V, min 1.6V, max 2.64V) and remains there until VDD rises above VTRIP + VTRIPHYS = 2.23V to 2.29V (VTRIPHYS = 10–60mV). Switchover also requires VDD < VBAT − VBATHYS (VBATHYS = 10–100mV). These values are specified in the DC Operating Characteristics table (page 3) and illustrated in Figures 11 and 12 of FN6316 Rev 1.00.
Can ISL1221IUZ-T generate a 1Hz square wave on FOUT, and how is it configured?
Yes, the ISL1221IUZ-T can output a precise 1Hz signal on FOUT. It is selected by setting FO<3:0> = 0x04 in the Frequency Output Control register (address 0x0E), per Table 10 on page 18 of FN6316 Rev 1.00. FOUT is an open-drain output requiring an external pull-up resistor; it remains high-impedance when disabled. The 1Hz option is one of 15 factory-trimmed frequencies derived from the 32.768kHz crystal, ensuring stability without external components.
ISL1221IUZ-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Time Event Recorder
- Features:
- Alarm, Leap Year, SRAM
- Memory Size:
- 2B
- 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):
- 4µA ~ 6µA @ 3V ~ 5V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 10-MSOP
ISL1221IUZ-T FAQ
1.How can I place an order for ISL1221IUZ-T through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL1221IUZ-T 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 ISL1221IUZ-T reliable?
The price and inventory of ISL1221IUZ-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL1221IUZ-T is usually 5 days.
3.What payment methods are accepted for ISL1221IUZ-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL1221IUZ-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL1221IUZ-T?
ISL1221IUZ-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL1221IUZ-T 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 ISL1221IUZ-T?
For technical support, including ISL1221IUZ-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL1221IUZ-T requirements.
6.How does Aetrix verify that ISL1221IUZ-T is sourced from the original manufacturer or authorized distributors?
All ISL1221IUZ-T 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 ISL1221IUZ-T meets industry standards.
7.What is the process for return or replacement of ISL1221IUZ-T?
All ISL1221IUZ-T units undergo pre-shipment inspection (PSI). If there is an issue with ISL1221IUZ-T, 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 ISL1221IUZ-T part is unused and in its original packaging.
Return procedure for ISL1221IUZ-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ISL1221IUZ-T 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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