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Diodes Incorporated PT7C4337UEX
- Part No.:
- PT7C4337UEX
- Manufacturer:
- Diodes Incorporated
- Category:
- Real Time Clocks
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
PT7C4337UEX.pdf
- Description:
- IC RTC CLK/CALENDAR I2C 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,226
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Product details
Overview
PT7C4337UEX from Diodes Incorporated is a low-power I²C real-time clock (RTC) module with BCD-coded time/calendar registers, two independent time-of-day alarms, and programmable square-wave output. It operates from 1.8V to 5.5V, maintains timekeeping down to 1.2V, supports 400 kHz I²C high-speed mode, and uses an external 32.768 kHz crystal for ±20 ppm typical accuracy in industrial temperature range (–40°C to +85°C). It is deployed in battery-backed embedded systems requiring precise timestamping and alarm-triggered wake-up.
For engineers reviewing the PT7C4337UEX datasheet, PT7C4337UEX pinout, PT7C4337UEX application, or PT7C4337UEX equivalent, key selection criteria include its dual-alarm interrupt flexibility (INTA/SQW-INTB configurable via INTCN), ultra-low 450 nA timekeeping current at 1.3V, BCD register mapping compatibility with legacy MCU firmware, and SOIC-8/W package suitability for space-constrained PCB layouts.
Technical Context
The PT7C4337UEX implements a fully autonomous timekeeping engine with automatic leap-year correction, month-end date rollover, and selectable 12/24-hour format - all maintained independently of host MCU activity. Its oscillator circuit includes built-in 12 pF load capacitors (CG/CD) and OSF flag detection for crystal failure monitoring.
I²C interface logic supports standard and fast-mode timing (tSU;DAT = 200 ns, fSCL ≤ 400 kHz), with open-drain SDA/SCL/INTA/SQW-INTB pins requiring external pull-ups. Alarm matching is performed in hardware using dedicated comparators against BCD-encoded registers; alarm flags (A1F/A2F) are latched and cleared only by software write.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.8 V to 5.5 V for full I²C operation; 1.2 V to 1.8 V for timekeeping-only mode |
| Timekeeping Current (ICCTOSC) | Typ. 450 nA at 1.3 V - enables >10-year coin-cell battery life in backup mode |
| I²C Clock Frequency | Up to 400 kHz - supports high-speed MCU host communication without bus arbitration delay |
| Square-Wave Output Frequencies | Selectable: 1 Hz, 4.096 kHz, 8.192 kHz, or 32.768 kHz - usable as system tick or clock source |
| Alarm Capability | Two independent alarms with maskable fields (seconds through day/date) - enables daily scheduler or periodic wake-up |
| Oscillator Fail Detection | OSF flag set on power-on, voltage drop, or crystal stop - provides deterministic clock validity check |
| Temperature Range | –40°C to +85°C - qualified for industrial and extended-temperature embedded applications |
Pinout & Package
PT7C4337UEX is packaged in an 8-pin SOIC (Wide) body (JEDEC MS-012AA, 3.9 mm width), with gull-wing leads and RoHS-compliant matte-tin plating. Pin 1 is marked by a beveled corner or dot; thermal pad is not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| X1 | Oscillator Input | Connects to one terminal of 32.768 kHz crystal; internal 12 pF capacitor to GND aids startup |
| X2 | Oscillator Output | Connects to other crystal terminal; must float if external clock applied instead of crystal |
| GND | Ground Reference | Primary return path for oscillator, I²C, and alarm outputs; connects to PCB ground plane |
| VCC | Power Supply | 1.8–5.5 V main supply; powers RTC core, I²C interface, and alarm logic |
| SQW/INTB | Configurable Output | Open-drain pin: outputs square wave (RS2/RS1-selectable) or Alarm 2 interrupt (INTCN=1) |
| SCL | I²C Clock Input | Input-only clock line; requires external pull-up; defines data transfer timing up to 400 kHz |
| SDA | I²C Data I/O | Open-drain bidirectional data line; requires external pull-up; handles address/data read/write |
| INTA | Alarm 1 Interrupt | Open-drain output asserted low on Alarm 1 match (if A1IE=1); shares no internal logic with SQW/INTB |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Calendar Correction | Hardware-level leap-year calculation and month-end date adjustment (e.g., Feb 28 → Mar 1) without MCU intervention |
| Dual Independent Alarms | Separate BCD registers and flag bits (A1F/A2F) allow concurrent scheduling of two distinct time-triggered events |
| Configurable Interrupt Routing | INTCN bit selects whether Alarm 2 triggers SQW/INTB (isolated) or INTA (shared), enabling flexible interrupt topology |
| Low-Voltage Timekeeping | Maintains accurate timekeeping at 1.2 V - critical for brown-out resilience during battery switchover |
| Crystal Oscillator Monitoring | OSF flag latches oscillator failure conditions (e.g., crystal fracture, contamination, or voltage sag) for diagnostic logging |
Applications
| Industrial PLC Timer | Smart Meter Timestamping |
|---|---|
|
Use Scenario: Programmable logic controller logs sensor events with millisecond-accurate timestamps across power cycles. IC Role / Device Role / Timing Role: Primary RTC providing BCD-formatted time/calendar data via I²C; maintains time during mains outage using backup battery. Use Value: Enables deterministic event sequencing and audit-trail compliance without relying on MCU real-time OS overhead. |
Use Scenario: Electricity meter records energy consumption intervals and tamper events with UTC-aligned timestamps. IC Role / Device Role / Timing Role: Time-of-day reference for billing cycle boundaries and firmware update scheduling; synchronized to utility network time. Use Value: Guarantees traceable, tamper-resistant time stamps meeting ANSI C12.1 and IEC 62056 standards. |
| Medical Wearable Sleep Tracker | POS Terminal Transaction Logging |
|
Use Scenario: Portable health monitor records sleep stage transitions and heart rate variability over multi-day sessions. IC Role / Device Role / Timing Role: Low-power timekeeper running continuously on CR2032; triggers daily data upload via Alarm 1 at fixed hour. Use Value: Achieves >36 months battery life while delivering clinically relevant temporal resolution (±1 sec/day). |
Use Scenario: Point-of-sale terminal logs transaction start/end times, cashier shifts, and firmware updates for PCI-DSS audit. IC Role / Device Role / Timing Role: Secure timestamp generator with OSF validation before each log entry to prevent clock rollback attacks. Use Value: Meets PCI-DSS requirement for immutable, verifiable time sources in payment processing environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar real-time clock applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS3231SN#T&R | Integrated TCXO (±2 ppm), higher accuracy, but 20 µA standby current vs. PT7C4337UEX's 450 nA | Preferred where precision > stability under voltage variation; unsuitable for ultra-low-power backup | Choose DS3231 when absolute time accuracy dominates battery life requirements |
| PCF8563T/2,118 | No square-wave output; single alarm; 0.25 µA timekeeping current; lacks OSF flag and INTCN routing | Used in cost-sensitive consumer devices where dual alarms and interrupt flexibility are unnecessary | Choose PCF8563 for minimal-feature RTCs in high-volume, price-driven designs |
Compared with DS3231SN and PCF8563T, PT7C4337UEX uniquely balances ultra-low timekeeping current (450 nA), dual-hardware alarms with configurable routing, and integrated oscillator fault detection - making it optimal for industrial and medical edge devices needing long battery life *and* robust time integrity verification.
Availability
PT7C4337UEX is available at Aetrix Electronics and suitable for industrial PLC timer modules, smart meter timestamping, and medical wearable sleep trackers requiring stable component supply, long-term lifecycle support, and guaranteed RoHS/Green compliance.
Supply support for PT7C4337UEX 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 PT7C4337UEX belongs to Diodes' precision timing product line, engineered specifically for battery-backed embedded systems demanding reliable, low-power timekeeping with diagnostic visibility into oscillator health.
FAQ
What is the minimum VCC required to retain timekeeping functionality?
The PT7C4337UEX maintains timekeeping operation down to 1.2 V, as verified in DC Electrical Characteristics (ICCTOSC test condition). Below 1.2 V, the oscillator stops and the OSF flag is set. This allows use with single-cell Li-MnO₂ or alkaline batteries that discharge below 1.8 V while preserving calendar accuracy during brown-out conditions.
How does the OSF (Oscillator Stop Flag) behave after power-up?
Upon initial power application, the OSF bit is set to logic 1 and remains asserted until explicitly cleared by writing 0 to bit 7 of register 0Fh. This ensures firmware can detect first-time initialization or prior oscillator failure before trusting time data - a mandatory step before enabling alarms or timestamping.
Can both alarms trigger simultaneously on the same interrupt pin?
Yes - when INTCN = 0, both Alarm 1 and Alarm 2 assert the INTA pin low if enabled (A1IE = A2IE = 1). The A1F and A2F flags remain individually latched in register 0Fh, allowing firmware to distinguish which alarm fired by reading status bits before clearing them.
What crystal load capacitance is recommended for optimal accuracy?
Diodes specifies two configurations: CL = 12.5 pF (requires 13 pF external capacitors on X1/X2) or CL = 6 pF (no external capacitors needed). Using a 32.768 kHz crystal with ESR ≤ 70 kΩ and matching the selected CL ensures <±20 ppm frequency deviation across –40°C to +85°C, per DS43089 Rev 2-2 Section 5.
PT7C4337UEX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, Leap Year, Square Wave Output
- Memory Size:
- -
- Time Format:
- HH:MM:SS (12/24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- I2C, 2-Wire Serial
- Voltage - Supply:
- 1.8V ~ 5.5V
- Voltage - Supply, Battery:
- -
- Current - Timekeeping (Max):
- 0.8µA @ 1.3V ~ 1.8V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-MSOP
PT7C4337UEX FAQ
1.How can I place an order for PT7C4337UEX through Aetrix?
Please submit a Request for Quotation (RFQ) for PT7C4337UEX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for PT7C4337UEX reliable?
The price and inventory of PT7C4337UEX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PT7C4337UEX is usually 5 days.
3.What payment methods are accepted for PT7C4337UEX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PT7C4337UEX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PT7C4337UEX?
PT7C4337UEX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PT7C4337UEX order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for PT7C4337UEX?
For technical support, including PT7C4337UEX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PT7C4337UEX requirements.
6.How does Aetrix verify that PT7C4337UEX is sourced from the original manufacturer or authorized distributors?
All PT7C4337UEX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PT7C4337UEX meets industry standards.
7.What is the process for return or replacement of PT7C4337UEX?
All PT7C4337UEX units undergo pre-shipment inspection (PSI). If there is an issue with PT7C4337UEX, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The PT7C4337UEX part is unused and in its original packaging.
Return procedure for PT7C4337UEX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
PT7C4337UEX Tags
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MCP7940N-I/SN
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MCP7940MT-I/MNY
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PCF85063ATL/1,118
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PCF85063AT/AY
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PCF85063TP/1Z
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PCF85063ATT/AJ
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