ISL12027IV27Z-T

Real Time Clock Overview

The ISL12027IV27Z-T is a low-power real-time clock/calendar integrated circuit manufactured by Renesas Electronics Corporation. 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 electrical parameters include a maximum timekeeping current of 20µA at 5.5V and a battery supply current of 1000nA at 3.0V. It utilizes an external 32.768kHz crystal and includes internal oscillator compensation. The component is housed in an 8-lead TSSOP package and is designated as obsolete.

Real Time Clock Feature Summary

• Integrated 512x8-bit EEPROM with 16-byte page write mode and 8 modes of BlockLock protection
• Two non-volatile alarms with repeat mode for periodic interrupts
• On-chip oscillator compensation with 64-position digitally controlled trim capacitors
• CPU Supervisor functions including Power-On Reset, Low Voltage Reset, and Watchdog Timer

Real Time Clock Applications

• Utility Meters
• HVAC Equipment
• Network Routers, Hubs, Switches, Bridges
• POS Equipment
• Home Appliances

Real Time Clock Procurement Notes

The ISL12027IV27Z-T is classified as an obsolete product with no recommended replacement available from the manufacturer. Verification of the specific ordering suffix '-T' confirms tape and reel packaging, distinct from tube packaging. Sourcing should focus on existing stock or authorized distributors, noting that availability is not guaranteed due to the end-of-life status.

Real Time Clock Selection Notes

Select this component only if legacy compatibility with the Intersil/Renesas ISL12027 family is required. The 'IV27' designation indicates an 8-lead TSSOP package with a VRESET threshold of 2.92V. Ensure the application design accommodates the obsolete status and potential supply constraints. Verify that the 400kHz I²C speed and 512-byte EEPROM capacity meet system requirements.

Real Time Clock Part Context

This part belongs to the ISL12027 series of real-time clocks. The base model ISL12027 uses Legacy Mode settings, while the ISL12027A variant uses Standard Mode settings. The ISL12027IV27Z specifically denotes the TSSOP package option with a 2.92V reset threshold. The '-T' suffix specifies tape and reel packaging for automated assembly.

Real Time Clock Replacement Considerations

The datasheet explicitly states there is no recommended replacement for this obsolete product. Engineers must contact the Technical Support Center for assistance. No direct pin-compatible or functionally equivalent substitutes are officially confirmed in the provided documentation.

Real Time Clock FAQ

What is the difference between the ISL12027 and ISL12027A power control settings?

The ISL12027 uses the Legacy Mode Setting, whereas the ISL12027A uses the Standard Mode Setting. Applications where VBAT > VDD require only the ISL12027A.

How does the device handle battery backup switching?

The device features intelligent battery backup switching. It automatically switches to the VBAT input when the VDD supply fails. The BSW bit determines the default setting for this switching behavior.

What is the maximum data transfer rate for the I²C interface?

The I²C bus interface supports a maximum data transfer rate of 400kHz.