Diodes Incorporated PT7C4372ALEX

Overview

PT7C4372ALEX from Pericom (now part of Diodes Incorporated) is a high-precision I²C real-time clock IC with integrated oscillator control logic, BCD time/calendar counters (year/month/date/hour/minute/second), dual alarm capability, and programmable periodic interrupts. It supports 32.768 kHz or 32.000 kHz external crystals, operates from 1.3 V to 6 V for timekeeping, and delivers ±3.051 ppm precision adjustment resolution with auto-leap-year calculation through 2099 - deployed in industrial metering and battery-backed embedded systems.

For engineers reviewing the PT7C4372ALEX datasheet, PT7C4372ALEX pinout, PT7C4372ALEX application, or PT7C4372ALEX equivalent, key selection criteria include its dual-interrupt-pin architecture (/INTA and /INTB), register-configurable 32-kHz clock output via /INTB, wide V_CC interface range (1.8–6 V), ultra-low 0.4 µA typical standby current at 3.0 V, and I²C high-speed mode (400 kHz) compliance.

Technical Context

The PT7C4372ALEX implements a fully autonomous RTC core with two independent alarm registers (Alarm_A and Alarm_B), each configurable by day/hour/minute, and a flexible periodic interrupt generator offering five timing intervals (0.5 s to monthly) with selectable pulse or level outputs. Its clock precision adjustment uses internal capacitor trimming to achieve ±3.051 ppm (32.768 kHz crystal) or ±3.125 ppm (32.000 kHz crystal) resolution.

Oscillation stop detection is implemented via register-flag monitoring to validate time data integrity after power-on or backup failure; the /INTB pin serves dual roles - as open-drain interrupt output and as 32-kHz square-wave clock source - controlled by SL2/SL1 bits in Control Register 1. The device requires no external load capacitors when paired with standard 32.768 kHz tuning-fork crystals.

Key Specifications

Pinout & Package

PT7C4372ALEX is housed in an 8-pin TSSOP package (3.0 mm × 4.4 mm, 0.65 mm pitch), optimized for space-constrained PCB layouts in portable and industrial equipment.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar real-time clock applications.

Compared with DS3231M and PCF8563, PT7C4372ALEX uniquely balances ultra-low power (0.4 µA), dual-interrupt flexibility, and field-adjustable precision - making it optimal for battery-powered industrial systems requiring concurrent timekeeping, alarm, and clock-output functions.

Availability

PT7C4372ALEX is available at Aetrix Electronics and suitable for smart energy metering, industrial PLC HMIs, medical wearable monitors, and IoT edge gateways requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for PT7C4372ALEX 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

Diodes Incorporated acquired Pericom in 2017 and integrates its high-performance timing and interface solutions into broad mixed-signal portfolios serving industrial, computing, and communications markets.

The PT7C4372A series belongs to Diodes' precision RTC product line, engineered specifically for battery-backed applications demanding robust timekeeping integrity, dual-alarm responsiveness, and register-level clock calibration - not general-purpose timing.

FAQ

Does PT7C4372ALEX require external load capacitors for the 32.768 kHz crystal?

No. The PT7C4372ALEX integrates oscillator circuitry with internal load capacitance optimized for standard 32.768 kHz tuning-fork crystals. External capacitors are unnecessary unless specified by the crystal manufacturer for frequency tolerance tightening - in which case only one capacitor (typically 12.5 pF) may be added between OSCIN and GND.

Can /INTA and /INTB output different interrupt types simultaneously?

Yes. Using SL2/SL1 bits in Control Register 1, /INTA can be assigned to Alarm_A + periodic interrupts while /INTB carries Alarm_B + 32-kHz clock output - or any of three other combinations. This enables concurrent, non-conflicting signaling to separate MCU interrupt lines without software arbitration.

What is the functional difference between PT7C4372A and PT7C4372C variants?

The PT7C4372C defaults to 24-hour time format (bit /12,24 = 1) and has CT2–CT0 reset to 0b011 (1 Hz periodic interrupt enabled), whereas PT7C4372A defaults to 12-hour format and CT2–CT0 = 0b000 (interrupts disabled). Both share identical pinout, electrical specs, and register map - only power-on defaults differ.

How does the clock precision adjustment function interact with the 32-kHz output on /INTB?

The 32-kHz square wave output on /INTB reflects the raw crystal frequency - it is not affected by the clock precision adjustment (trimming) register. Trimming adjusts only the internal time counter's increment rate; the FOUT signal remains unmodified, preserving its use as a stable system clock source independent of timekeeping calibration.