My Inquiry
My Account
Renesas ISL1209IU10
- Part No.:
- ISL1209IU10
- Manufacturer:
- Renesas
- Category:
- Real Time Clocks
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
ISL1209IU10.pdf
- Description:
- IC RTC EVENT REC I2C 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,710
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
ISL1209IU10 from Renesas (formerly Intersil) is a low-power real-time clock IC with integrated event detection, battery-backed 2-byte SRAM, I²C interface, and programmable frequency output. It tracks time and calendar (hours/minutes/seconds/date/month/year/day-of-week) with leap-year correction through 2099, operates from 2.7V to 5.5V, draws only 400nA from VBAT, and supports tamper detection in both main and backup power modes - used in utility meters and security systems.
For engineers reviewing the ISL1209IU10 datasheet, ISL1209IU10 pinout, ISL1209IU10 application, or ISL1209IU10 equivalent, this page delivers verified technical context, confirmed pin functions, validated alternatives, and design-meaningful specifications - including crystal compensation range (−94ppm to +140ppm), event sampling rates (1/4 Hz to 2 Hz), IRQ/FOUT dual-mode operation, and VBAT switchover thresholds (VTRIP = 2.2V ±0.4V).
Technical Context
The ISL1209IU10 implements a crystal-based RTC using an external 32.768kHz quartz oscillator with on-chip analog (ATR) and digital (DTR) trimming for temperature-compensated accuracy (−94ppm to +140ppm). Its event detection circuit supports configurable sampling (1/4 Hz, 1 Hz, 2 Hz) and glitch filtering (0, 3.9 ms, 15.6 ms, 31.25 ms) to minimize current draw while maintaining reliability in tamper monitoring.
I²C communication runs at up to 400kHz with open-drain SDA/SCL, automatic deactivation in battery backup mode, and full register access to RTC, alarm, control/status, and user SRAM sections. Power management includes intelligent VDD-to-VBAT switchover (VTRIP ≈ 2.2V, VBATHYS ≈ 50mV), Low Power Mode (LPMODE), and InterSeal™ Battery Saver to prevent pre-use battery drain.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDD Range | 2.7V to 5.5V - supports wide-input industrial and telecom power rails without external regulation. |
| VBAT Supply Current | 400nA typical at 3V - enables >10-year lithium battery life in metering and security applications. |
| I²C Speed | 400kHz - compatible with standard Fast-Mode I²C controllers without timing margin concerns. |
| Crystal Compensation | −94ppm to +140ppm - corrects for temperature-induced drift via ATR/DTR registers for ±1 min/month accuracy. |
| Event Sampling Rates | 1/4 Hz, 1 Hz, 2 Hz - selectable trade-off between detection latency and sub-µA power savings in battery mode. |
| Alarm Flexibility | Settable to second, minute, hour, day-of-week, date, or month - enables precise scheduling (e.g., "every Tuesday at 3:15 AM"). |
| RTC Calendar Range | Accurate through year 2099 with automatic leap-year correction - eliminates firmware date-handling overhead. |
| Package | 10-lead MSOP (M10.118) - compact footprint for space-constrained embedded designs; RoHS-compliant Pb-free option available. |
Pinout & Package
ISL1209IU10 is housed in a 10-lead MSOP package (M10.118), 3.0mm × 4.9mm × 1.0mm body, exposed pad optional, moisture sensitivity level (MSL) 1 at Pb-free peak reflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 X1 | Clock Input | Inverting amplifier input for 32.768kHz crystal; accepts direct 32.768kHz square-wave drive if X2 left open. |
| 2 X2 | Clock Output | Inverting amplifier output for crystal connection; must be left floating when X1 is externally driven. |
| 3 VBAT | Backup Supply | Provides power during VDD failure; supports lithium batteries or supercaps; active down to 1.8V. |
| 4 GND | Ground Reference | Common return for all analog/digital circuits; requires low-impedance connection to minimize noise coupling. |
| 5 EVIN | Event Input | Detects high-level tamper signals (e.g., door switch); configurable sampling rate and glitch filter (0–31.25ms). |
| 6 EVDET | Event Output | Open-drain active-low output asserting on EVIN trigger; remains low until EVT bit is cleared via I²C. |
| 7 SDA | I²C Data | Bidirectional open-drain serial data line; requires external pull-up; disabled in VBAT-only mode. |
| 8 SCL | I²C Clock | Input-only serial clock line; always active in VDD mode; gated off in VBAT mode to reduce leakage. |
| 9 IRQ/FOUT | Multi-function I/O | Configurable as interrupt (open-drain active-low) or frequency output (15 selectable values up to 32kHz). |
| 10 VDD | Main Supply | Primary power input; powers all logic and interfaces; triggers automatic switchover to VBAT when below VTRIP. |
Key Features
| Feature | Design Value |
|---|---|
| Intelligent Battery Switchover | Automatic VDD-to-VBAT transition with hysteresis (≈50mV) and VTRIP threshold (2.2V) prevents oscillation during brownout. |
| Tamper Detection with Timestamp | EVIN-triggered event captures exact RTC time and halts register advancement - critical for forensic security logging. |
| On-Chip Oscillator Compensation | Combined ATR (capacitance trim) and DTR (counter offset) enable factory or runtime calibration for ±1 min/month accuracy. |
| InterSeal™ Battery Saver | Zero pre-use battery drain: VBAT current only flows after first VDD power-up - extends shelf life of battery-equipped modules. |
| Low-Power Event Monitoring | Sub-100nA incremental current increase (e.g., +20.5nA at 1/4Hz sampling, VDD=3V) enables years-long tamper vigilance. |
| Single Alarm with Pulse/Repeat Modes | IRQ pulse lasts 250ms in repeat mode; ALM bit auto-clears or persists per ARST setting - simplifies host interrupt handling. |
Applications
| Utility Metering | Security & Tamper Monitoring |
|---|---|
Use Scenario: Time-stamping energy consumption data in smart electricity/water/gas meters with long-term battery backup. IC Role / Device Role / Timing Role: Primary RTC and calendar source; maintains accurate billing timestamps across multi-year battery life. Use Value: Eliminates need for external timekeeping or MCU-based calendar logic; 2099 leap-year support ensures decade-long firmware stability. |
Use Scenario: Detecting unauthorized enclosure opening in network routers, POS terminals, or test fixtures. IC Role / Device Role / Timing Role: Tamper sensor with hardware timestamping; stops RTC on event to preserve exact intrusion time. Use Value: Provides forensically reliable, battery-backed event log independent of host processor state or power loss. |
| Network Infrastructure | Industrial Control & Test Equipment |
Use Scenario: Maintaining system uptime logs and configuration timestamps in switches, hubs, and cellular baseband units. IC Role / Device Role / Timing Role: System clock/calendar with power-fail detection (RTCF bit) and alarm-driven maintenance alerts. Use Value: Enables deterministic diagnostics after unexpected power cycles; alarm can trigger watchdog reset or status LED blink patterns. |
Use Scenario: Recording calibration timestamps and fault events in portable test meters and automated test fixtures. IC Role / Device Role / Timing Role: Standalone timekeeper with battery-backed SRAM storing last-calibration date and operator ID. Use Value: Preserves traceability-critical metadata even during extended storage or field deployment without mains power. |
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 |
|---|---|---|---|
| Maxim MAX31342 | Integrated 32.768kHz oscillator (no external crystal); 1.8V–5.5V VDD; 128B battery-backed SRAM; no event sampling rate control. | Lacks configurable event sampling and glitch filtering; higher integration reduces BOM count but limits tamper response tuning. | Choose MAX31342 when crystal omission and larger SRAM outweigh need for fine-grained event power optimization. |
| Analog Devices ADT7411 | Combines 10-bit ADC + temperature sensor + RTC; no event detection; 2-wire interface; 3.0V–5.5V only; no VBAT switchover. | Not a drop-in replacement: lacks tamper inputs, battery backup switching, and SRAM - serves hybrid sensing+timing roles. | Choose ADT7411 only when simultaneous temperature monitoring and basic RTC are required, and event detection is handled externally. |
Compared with MAX31342 and ADT7411, the ISL1209IU10 uniquely balances ultra-low VBAT current (400nA), flexible event monitoring (sampling + filtering), and crystal-based timing precision - making it optimal for long-life, tamper-aware metering and infrastructure applications where external crystal cost is acceptable.
Availability
ISL1209IU10 is available at Aetrix Electronics and suitable for utility metering, network infrastructure, security systems, industrial test equipment, and tamper-evident embedded devices requiring stable component supply over extended production lifecycles.
Supply support for ISL1209IU10 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 Corporation acquired Intersil in 2017 and maintains full product support, documentation, and manufacturing continuity for legacy Intersil timing and power management ICs.
The ISL1209IU10 belongs to Renesas' low-power real-time clock family designed for battery-critical applications requiring tamper resilience, calendar accuracy through 2099, and seamless VDD/VBAT switchover - targeting metering, infrastructure, and security markets.
FAQ
What is the minimum VBAT voltage required for ISL1209IU10 to retain RTC and SRAM functionality?
The ISL1209IU10 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 operating range, with typical battery supply current of 400nA at 3V - enabling >10-year operation on common lithium coin cells. This 1.8V retention floor is confirmed in DC Operating Characteristics (Page 3) and General Description (Page 7) of FN6109 Rev 4.00.
Does ISL1209IU10 support I²C communication while running solely on VBAT?
No, the I²C interface (SDA and SCL) is automatically disabled during VBAT-only operation to minimize current draw. Only the RTC, alarm, event detection, and IRQ/FOUT functions remain active. Register access and SRAM reads/writes require VDD presence. This behavior is explicitly stated in the Functional Description section (Page 8) and Pin Descriptions (Page 2), ensuring predictable low-power operation when mains power fails.
How does the ISL1209IU10 handle leap years and month-end date rollovers?
The ISL1209IU10 implements fully autonomous calendar logic: it correctly advances from February 28 to March 1 in non-leap years, February 29 to March 1 in leap years (e.g., 2024, 2028), and handles 30-day months (April, June, etc.) and 31-day months without firmware intervention. The datasheet confirms accuracy through 2099 with automatic leap-year correction - verified in General Description (Page 7) and Register Map (Page 12) where DW (day-of-week) and DT (date) registers update synchronously.
Can the ISL1209IU10 generate a 1Hz square wave output, and how is it configured?
Yes, the ISL1209IU10 can output a precise 1Hz signal on the IRQ/FOUT pin by programming the FO bits (bits 6–4 of Control Register at address 07h) to value 0x07. This is one of 15 selectable frequencies ranging from 0Hz (off) to 32768Hz. Configuration is performed via I²C write to the control register; the output is open-drain and requires an external pull-up resistor. This capability is documented in Frequency Output Mode (Page 10) and Register Descriptions (Page 11).
What is the purpose of the InterSeal™ Battery Saver feature in ISL1209IU10?
InterSeal™ Battery Saver prevents any current draw from the VBAT source until the ISL1209IU10 is powered for the first time from VDD - eliminating shelf-life degradation in pre-battery-assembled modules. Once VDD is applied and removed, normal VBAT switchover resumes. This feature is detailed in Functional Description (Page 9) and directly addresses a key reliability concern in metering and security products shipped with installed batteries.
ISL1209IU10 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- 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
ISL1209IU10 FAQ
1.How can I place an order for ISL1209IU10 through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL1209IU10 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 ISL1209IU10 reliable?
The price and inventory of ISL1209IU10 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL1209IU10 is usually 5 days.
3.What payment methods are accepted for ISL1209IU10?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL1209IU10 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL1209IU10?
ISL1209IU10 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL1209IU10 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 ISL1209IU10?
For technical support, including ISL1209IU10 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL1209IU10 requirements.
6.How does Aetrix verify that ISL1209IU10 is sourced from the original manufacturer or authorized distributors?
All ISL1209IU10 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 ISL1209IU10 meets industry standards.
7.What is the process for return or replacement of ISL1209IU10?
All ISL1209IU10 units undergo pre-shipment inspection (PSI). If there is an issue with ISL1209IU10, 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 ISL1209IU10 part is unused and in its original packaging.
Return procedure for ISL1209IU10:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ISL1209IU10 Tags
-
MCP7940N-I/SN
Microchip Technology
-
MCP7940MT-I/MNY
Microchip Technology
-
PCF85063ATL/1,118
NXP USA Inc.
-
MCP7940NT-I/SN
Microchip Technology
-
MCP7940NT-I/MS
Microchip Technology
-
MCP7940N-I/MS
Microchip Technology
-
PCF85063AT/AY
NXP USA Inc.
-
PCF85063TP/1Z
NXP Semiconductors
-
PCF85063ATT/AJ
NXP USA Inc.
-
MCP7940NT-E/SN
Microchip Technology
-
MCP7940NT-I/MNY
Microchip Technology
-
MCP79400T-I/SN
Microchip Technology
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
