PT7C4337LEX

Real Time Clock Overview

The PT7C4337LEX is a Real-Time Clock (RTC) module manufactured by Diodes Incorporated, housed in an 8-pin TSSOP package. It operates on a 2-wire I2C bus interface with a supply voltage range of 1.2V to 5.5V. The device supports both 12-hour and 24-hour time formats, tracking seconds, minutes, hours, days of the week, dates, months, and years. Key features include two programmable alarms, a programmable square wave output, oscillator fail detection, and low power consumption modes for timekeeping and data retention.

Real Time Clock Feature Summary

• I2C Bus Interface: Supports standard communication up to 400 kHz.
• Dual Alarms: Two independent alarm registers with configurable mask bits for various trigger rates.
• Low Power Operation: Timekeeping current is typically 450nA at 1.8V; data retention current is under 160nA.
• Oscillator Features: External 32.768kHz crystal support with built-in capacitors and oscillator stop flag detection.

Real Time Clock Applications

• Embedded systems requiring precise timekeeping and calendar functions.
• Battery-powered devices utilizing low standby current modes.
• Industrial equipment operating within -40°C to +85°C temperature ranges.
• Consumer electronics needing alarm or interrupt generation capabilities.

Real Time Clock Procurement Notes

Verify the ordering suffix 'LEX' corresponds to the 8-pin TSSOP package variant. Confirm RoHS compliance status as per manufacturer definitions. Ensure external pull-up resistors are included for SDA, SCL, INTA, and SQW/INTB pins due to open-drain outputs. Check for availability of the specific tape-and-reel packaging if indicated by additional suffixes.

Real Time Clock Selection Notes

Select this component when an I2C-compatible RTC with dual alarms and low power consumption is required. Ensure the application voltage falls within the 1.2V to 5.5V range. Consider the 8-pin TSSOP package constraints for PCB layout. Verify that the external crystal load capacitance requirements match the system design, noting the internal 12pF capacitors.

Real Time Clock Part Context

The PT7C4337 series includes variants such as PT7C4337WEX (SOIC), PT7C4337UEX (MSOP), and PT7C4337ZEEX (TDFN). The LEX suffix specifically denotes the 8-pin, 173mil wide TSSOP package. All variants share identical electrical characteristics and functionality, differing only in physical package dimensions and pinout geometry.

Real Time Clock Replacement Considerations

Direct replacements must maintain I2C compatibility, similar voltage ranges, and package dimensions. Cross-reference with other Diodes Incorporated RTC models or industry-standard equivalents like DS1307, ensuring pinout compatibility or adapter usage. Verify register mapping differences if substituting with functionally similar parts from other manufacturers.

Real Time Clock FAQ

What is the default square wave output frequency?

The default square wave output frequency is 32.768 kHz, determined by the RS2 and RS1 control bits being set to '11'.

Does the PT7C4337 support century bit calculation?

No, the PT7C4337 does not support a century bit. It tracks years in a 00-99 format.

How is the oscillator stop detected?

The OSF (Oscillator Stop Flag) bit in the Status Register (Address 0Fh) indicates if the oscillator has stopped. This flag is set when the oscillator fails and can be cleared by writing a logic 0.