Diodes Incorporated PT7C433833AZEEX

Overview

PT7C433833AZEEX from Diodes Incorporated is a real-time clock (RTC) module with I²C interface, 32.768 kHz crystal oscillator, 56×8-bit RAM, battery backup support, and programmable square-wave output at 1 Hz / 4.096 kHz / 8.192 kHz / 32.768 kHz. It operates from 2.7 V to 5.5 V and maintains timekeeping during main power loss using a 3 V lithium cell on VBAT.

For engineers reviewing the PT7C433833AZEEX datasheet, PT7C433833AZEEX pinout, PT7C433833AZEEX application, or PT7C433833AZEEX equivalent, key selection criteria include I²C timing compliance (400 kHz max), oscillator fail detection, low-power battery-retention current (≤300 nA), and SOIC/MSOP/TDFN package compatibility in space-constrained embedded systems.

Technical Context

The PT7C433833AZEEX integrates a precision 32.768 kHz crystal oscillator with built-in 20 pF load capacitors and supports external crystal tuning via 4 pF external caps. Its oscillator stop flag (OSF) detects crystal failure within 100 ms and latches status for system diagnostics.

I²C communication uses standard- and fast-mode timing (tLOW ≥1.3 μs, tHIGH ≥0.6 μs, CB ≤400 pF), with open-drain SDA/SQW/OUT pins requiring external pull-ups. The device supports both 12- and 24-hour time formats, century bit–capable calendar registers (00–99 years), and automatic address increment during sequential reads/writes.

Key Specifications

Pinout & Package

PT7C433833AZEEX is packaged in an 8-pin TDFN (2 mm × 3 mm, ZE code), with wettable flank leads for automated optical inspection. Thermal pad exposed on underside improves thermal dissipation in high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS3231M and PCF8563, PT7C433833AZEEX delivers balanced performance: superior oscillator monitoring (OSF) vs. PCF8563, lower cost and simpler layout (integrated 20 pF caps) vs. DS3231M, and optimal package flexibility (TDFN/SOIC/MSOP) for mixed-density designs.

Availability

PT7C433833AZEEX is available at Aetrix Electronics and suitable for industrial PLCs, smart meters, and medical wearables requiring stable component supply, long-term lifecycle support, and RoHS 3-compliant packaging.

Supply support for PT7C433833AZEEX 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 is a global manufacturer of discrete semiconductors and integrated circuits, specializing in power management, signal integrity, and timing solutions for industrial, computing, and consumer markets.

The PT7C433833 series belongs to Diodes' precision timing product line, designed specifically for cost-sensitive, space-constrained embedded systems needing reliable, low-power RTC functionality with battery backup and I²C simplicity.

FAQ

What is the function of the OSF (Oscillator Stop Flag) bit in the Control register?

The OSF bit (bit 5 of register 07h) indicates whether the internal 32.768 kHz oscillator has stopped due to crystal failure, disconnection, or excessive load capacitance mismatch. It is latched until cleared by writing '0' to the bit, enabling firmware to detect and log timekeeping faults before corrupted timestamps propagate through the system.

Can PT7C433833AZEEX operate without an external crystal?

No - the device requires either a 32.768 kHz crystal connected between X1 and X2, or an external 32.768 kHz oscillator signal applied to X1 (with X2 floated). The internal oscillator circuit is not functional without one of these sources; there is no internal RC oscillator or factory-trimmed alternative.

How does the VCC-to-VBAT switchover behave during power failure?

When VCC falls below the power-fail threshold (VPF = 1.5–2.0 V), the device automatically disables register access but continues timekeeping and RAM retention using VBAT. Reads/writes resume only after VCC rises above VPF and a 2 ms recovery delay elapses - ensuring register consistency after brownout recovery.

Is the SQW/OUT pin capable of driving a microcontroller interrupt input directly?

Yes - SQW/OUT is an open-drain output compatible with standard CMOS logic levels. When pulled up to VCC or VBAT (via 4.7 kΩ–10 kΩ resistor), it can assert a low-level interrupt to a GPIO pin configured with falling-edge detection, enabling precise wake-up or periodic task triggering without additional level-shifting circuitry.