PT7C4337LE

Real Time Clock Overview

The PT7C4337LE 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 1.8V to 5.5V and supports timekeeping down to 1.2V. The device tracks seconds, minutes, hours, days, dates, months, and years using BCD format, supporting both 12-hour and 24-hour modes. Key features include two programmable alarms, a programmable square wave output, oscillator fail detection, and low power consumption.

Real Time Clock Feature Summary

• I2C Bus Interface: Supports standard mode up to 400 kHz for efficient communication with host microcontrollers.
• Dual Alarm System: Features two independent alarm registers (Alarm 1 and Alarm 2) with configurable mask bits for various trigger rates.
• Low Power Operation: Maintains timekeeping at VCC = 1.2V to 1.8V with typical current consumption of 450nA; data retention current is under 160nA.
• Programmable Outputs: Provides a programmable square wave output (1Hz, 4.096kHz, 8.192kHz, or 32.768kHz) and dedicated interrupt pins.

Real Time Clock Applications

• Battery-powered portable electronics requiring precise time tracking.
• Embedded systems needing calendar functions and periodic wake-up interrupts.
• Industrial control units operating within -40°C to +85°C temperature ranges.

Real Time Clock Procurement Notes

Verify the ordering suffix 'L' corresponds to the 8-pin TSSOP package when sourcing. Confirm RoHS compliance status as per manufacturer specifications. Ensure external pull-up resistors are included for SDA, SCL, INTA, and SQW/INTB lines due to open-drain configurations. Validate crystal load capacitance requirements against the specific 32.768kHz crystal selected for the design.

Real Time Clock Selection Notes

Select this component if an I2C interface and dual alarm capabilities are required. The PT7C4337LE lacks a century bit, limiting year tracking to 00-99. For designs requiring a wider supply voltage range below 1.8V during active operation, verify that the 1.2V minimum applies only to timekeeping mode. Ensure the application can accommodate the necessary external 32.768kHz crystal and capacitors for oscillator stability.

Real Time Clock Part Context

The PT7C4337LE belongs to the PT7C4337 family from Diodes Incorporated. The 'L' suffix specifically denotes the 8-pin TSSOP (173mil wide) package variant. Other variants in the series include W (SOIC), U (MSOP), and ZE (TDFN). All variants share identical electrical characteristics and functional register maps.

Real Time Clock Replacement Considerations

Direct pin-to-pin replacements within the same package require checking I2C address compatibility and register mapping. Verify that alternative RTCs support the same 1.2V timekeeping voltage if low-power standby is critical. Ensure substitute components offer comparable alarm flexibility and interrupt pin configurations.

Real Time Clock FAQ

Does the PT7C4337LE support automatic leap year correction?

Yes, the internal calendar counter automatically accounts for leap years until the year 2100.

What is the default I2C slave address for the PT7C4337?

The default 7-bit slave address is 1101000 (0x68). Write operations use 0xD0, and read operations use 0xD1.

How is the oscillator stop detected?

The OSF (Oscillator Stop Flag) bit in the Status Register (Address 0Fh) is set to logic 1 when the oscillator stops running. This flag must be cleared by writing a logic 0.