Diodes Incorporated PT7C4307WEX

Overview

PT7C4307WEX from Diodes Incorporated is a serial real-time clock (RTC) IC with I²C interface, battery-backed 56-byte NV RAM, programmable square-wave output (1 Hz / 4.096 kHz / 8.192 kHz / 32.768 kHz), automatic leap-year calendar correction, and <500 nA battery-backup current consumption. It serves as a system timekeeping engine in embedded controllers requiring accurate date/time stamping and low-power backup operation - e.g., industrial HMIs, smart meters, and medical data loggers.

For engineers reviewing the PT7C4307WEX datasheet, PT7C4307WEX pinout, PT7C4307WEX application, or PT7C4307WEX equivalent, key selection criteria include I²C high-speed mode (400 kHz) support, BCD-coded time/calendar registers, oscillator fail detection, VBAT switchover logic, and SOIC-W package compatibility for space-constrained PCB layouts.

Technical Context

The PT7C4307WEX implements a fully autonomous BCD-based counter chain for seconds, minutes, hours, day-of-week, date, month, and year - including automatic end-of-month and leap-year adjustment up to year 2099. Its oscillator circuit interfaces directly with a 32.768 kHz crystal via X1/X2 pins and includes built-in 20 pF load capacitors.

Power management integrates a comparator-based power-fail detector that triggers seamless switchover from VCC (4.5–5.5 V) to VBAT (2.0–3.5 V) without time loss. The SQW/OUT pin delivers selectable square-wave outputs synchronized to the RTC clock domain, while SDA operates as open-drain requiring external pull-up.

Key Specifications

Pinout & Package

PT7C4307WEX is housed in an 8-pin SOIC (Wide) package (body width 5.3 mm), RoHS-compliant and halogen-free, suitable for reflow soldering and automated assembly.

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 PT7C4307WEX delivers optimal balance: crystal-based accuracy with integrated load caps, 56-byte RAM, four-frequency SQW output, and sub-500 nA backup current - making it ideal for industrial and medical applications needing long-life, feature-rich, cost-efficient timekeeping.

Availability

PT7C4307WEX is available at Aetrix Electronics and suitable for industrial data loggers, smart energy meters, medical patient monitors, and POS terminals requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PT7C4307WEX 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 analog ICs, specializing in high-reliability, low-power, and automotive-qualified components for industrial, computing, and consumer markets.

The PT7C4307WEX belongs to Diodes' precision timing product line, designed specifically for embedded systems requiring robust, battery-backed real-time clock functionality with minimal external components and extended operational lifetime.

FAQ

What crystal specifications are required for PT7C4307WEX?

The PT7C4307WEX requires a 32.768 kHz tuning-fork crystal with 12.5 pF load capacitance, series resistance ≤70 kΩ, and stability rated for −40 °C to +85 °C operation. Its internal 20 pF load capacitors (CG/CD) reduce or eliminate need for external C1/C2 caps when paired with a properly specified crystal.

How does the power-fail switchover work without time loss?

The PT7C4307WEX integrates an on-chip comparator that continuously monitors VCC against a threshold derived from VBAT (1.216× to 1.284×). When VCC drops below this threshold, the device automatically switches to VBAT within nanoseconds - maintaining oscillator oscillation and register state without interruption or reset.

Can the SQW/OUT pin drive an MCU interrupt directly?

Yes - SQW/OUT is an open-drain output with 3.5 mA sink capability. When configured for 1 Hz output, it can directly assert a low-active interrupt on most MCUs (e.g., ARM Cortex-M EXTI lines) without level-shifting or buffering, provided a pull-up resistor (typically 4.7 kΩ to VCC_IO) is used.

Is the 56-byte RAM volatile or nonvolatile during main power loss?

The 56-byte RAM is nonvolatile during main power loss: it remains powered by VBAT and retains data as long as VBAT ≥2.0 V. Unlike standard SRAM, it requires no refresh and preserves contents across decades of battery-backed operation - confirmed by Diodes' accelerated retention testing per JEDEC JESD22-A117.