Diodes Incorporated PT7C433833UEX

Overview

PT7C433833 from Diodes Incorporated is a low-power I²C real-time clock (RTC) module with integrated 32.768 kHz crystal oscillator interface, BCD-coded time/calendar registers (seconds to years), 56-byte battery-backed nonvolatile RAM, and programmable square-wave output (1 Hz / 4.096 kHz / 8.192 kHz / 32.768 kHz). It supports automatic leap-year correction and operates in 12- or 24-hour format for industrial control panels requiring accurate timestamping under intermittent power.

For engineers reviewing the PT7C433833 datasheet, PT7C433833 pinout, PT7C433833 application, or PT7C433833 equivalent, key selection criteria include I²C fast-mode (400 kHz) compatibility, VBAT data retention current (<300 nA), power-fail detection threshold (2.59 V), and MSOP-8 package suitability for space-constrained embedded timing designs.

Technical Context

The PT7C433833 implements a fully autonomous timekeeping engine with hardware-based calendar logic that auto-adjusts month-end dates-including February in leap years-and maintains century-aware year counting up to 2100. Its oscillator circuit includes fail-detection flag (OSF) and enable/disable control (/EOSC) for system-level fault monitoring.

I²C communication uses open-drain SDA/SCL with external pull-up support, compliant with Fast-mode timing (tLOW ≥ 1.3 μs, tHIGH ≥ 0.6 μs). The SQW/OUT pin delivers selectable square-wave outputs referenced to either VCC or VBAT, enabling direct connection to microcontroller interrupt or clock-input pins without level-shifting.

Key Specifications

Pinout & Package

PT7C433833 is housed in an 8-pin MSOP (U) package with 0.65 mm pitch and exposed thermal pad (not electrically connected). The compact 3.0 × 3.0 mm footprint supports high-density PCB layouts in industrial and automotive modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS3231M and PCF8563, the PT7C433833 uniquely balances ultra-low VBAT retention current (300 nA), hardware calendar intelligence, and flexible SQW output - making it optimal for industrial and medical systems needing long-term reliability without TCXO cost penalties.

Availability

PT7C433833 is available at Aetrix Electronics and suitable for industrial PLC timer modules, smart energy meters, automotive telematics units, and medical infusion pumps requiring stable component supply across extended product lifecycles.

Supply support for PT7C433833 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 semiconductor company specializing in discrete, analog, and mixed-signal ICs for power management, signal integrity, and timing solutions.

The PT7C433833 belongs to Diodes' precision RTC product line, engineered for industrial and automotive applications demanding robust timekeeping, low-power backup operation, and regulatory compliance (UL, RoHS, AEC-Q200 readiness).

FAQ

Does PT7C433833 require external load capacitors for the 32.768 kHz crystal?

Yes - the device integrates 20 pF internal load capacitors (CG and CD), but external 4 pF capacitors (C1 and C2) are recommended to achieve optimal 32.768 kHz oscillation with standard 12.5 pF-load crystals. Layout guidelines specify isolation from RF noise sources to prevent frequency drift or startup failure.

How does the OSF (Oscillator Stop Flag) behave after power-up?

The OSF bit is set to logic 1 on first power application and remains asserted until explicitly cleared by writing 0 to bit 3 of register 07h. It also activates if VCC/VBAT drops below oscillation threshold, /EOSC is set, or crystal is disturbed - serving as a persistent fault indicator until software validation.

Can PT7C433833 operate with VCC = 0 V while retaining timekeeping?

Yes - when VCC = 0 V and VBAT is within 1.5–3.7 V, the RTC continues timekeeping and calendar functions uninterrupted. However, I²C communication and RAM writes are disabled; only read access to time registers remains functional under VBAT-only operation.

What is the maximum total bus capacitance supported for I²C Fast-mode operation?

The PT7C433833 supports up to 400 pF total capacitance per I²C bus line (CB) in Fast-mode, with rise/fall times specified at ≤300 ns. This allows daisy-chaining up to ~5–7 slave devices on a single bus segment using standard 4.7 kΩ pull-ups at 3.3 V.