ISL12027IV27Z

Real Time Clock Overview

The ISL12027IV27Z is a low-power Real Time Clock (RTC) and calendar integrated circuit manufactured by Renesas Electronics. It features an I2C bus interface, two non-volatile alarms, and 512x8-bit EEPROM with BlockLock protection. The device operates on a main supply voltage of 2.7V to 5.5V and supports battery backup down to 1.8V. Key specifications include a battery supply current of 800nA at 1.8V, a watchdog timer, and low voltage reset functions. It utilizes an external 32.768kHz crystal and includes on-chip oscillator compensation for accuracy across the -40°C to +85°C operating temperature range.

Real Time Clock Feature Summary

• I2C Interface: Supports up to 400kHz data transfer rate with open-drain SDA/SCL pins.
• On-Chip Oscillator Compensation: Includes internal feedback resistor and 64-position digitally controlled trim capacitor for frequency adjustment within ±30ppm.
• Integrated Memory: Contains 512x8-bit EEPROM with 16-byte page write mode and 8 modes of BlockLock protection.
• Supervisory Functions: Features a watchdog timer, power-on reset, and low voltage reset with selectable trip thresholds.

Real Time Clock Applications

• Utility Meters
• HVAC Equipment
• Network Routers, Hubs, Switches, Bridges
• POS Equipment
• Industrial Controls

Real Time Clock Procurement Notes

The ISL12027IV27Z is classified as an obsolete product with no recommended replacement from the manufacturer. Verification of component authenticity and physical condition is critical when sourcing from secondary markets. Ensure compatibility with legacy system designs before procurement, as direct functional substitutes are not officially designated.

Real Time Clock Selection Notes

Select this component for applications requiring precise timekeeping with integrated non-volatile storage and supervisory controls. Verify that the VBAT threshold settings align with the specific battery or supercapacitor configuration in the design. Note that the ISL12027 uses Legacy Mode Power Control Settings, which differ from the ISL12027A Standard Mode.

Real Time Clock Part Context

This part belongs to the ISL12027 family of real-time clocks. The 'IV' suffix indicates an 8-lead TSSOP package, while '27' specifies a VRESET voltage level of approximately 2.92V. The 'AZ' suffix denotes RoHS compliance and lead-free packaging. This variant is distinct from the ISL12027A series regarding power control configurations.

Real Time Clock Replacement Considerations

The datasheet explicitly states there is no recommended replacement for this obsolete product. Designers must evaluate third-party alternatives based on pinout compatibility, electrical specifications, and software register mapping, as no official cross-reference is provided by Renesas.

Real Time Clock FAQ

["What is the battery supply current consumption?","The battery supply current (IBAT) is typically 800nA at VBAT = 1.8V and 850nA at VBAT = 3.0V, measured with VDD, SCL, SDA, and RESET grounded."]

["How does the device handle oscillator accuracy?","The ISL12027 integrates an on-chip oscillator compensation network with a 64-position digitally controlled trim capacitor and internal feedback resistor, allowing frequency adjustment to compensate for crystal variations over temperature."]

["What is the function of the RESET pin?","The RESET pin is an open-drain active LOW output that signals a host processor when the watchdog timer expires or when the VDD supply drops below the specified VRESET threshold."]