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NXP Semiconductors PCA2129T/Q900/2,51
- Part No.:
- PCA2129T/Q900/2,51
- Manufacturer:
- NXP Semiconductors
- Category:
- Real Time Clocks
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
PCA2129T/Q900/2,51.pdf
- Description:
- IC RTC CLOCK/CALENDAR I2C 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,656
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Product details
Overview
PCA2129T/Q900/2 from NXP Semiconductors is an automotive-grade CMOS Real-Time Clock (RTC) with integrated temperature-compensated crystal oscillator (TCXO) and 32.768 kHz quartz crystal, delivering ±3 ppm accuracy from −30 °C to +80 °C, operating from 1.8 V to 4.2 V, and consuming only 0.70 μA typical supply current at 3.3 V - used for precision timekeeping in battery-backed automotive and industrial metering systems.
For engineers reviewing the PCA2129T/Q900/2 datasheet, PCA2129T/Q900/2 pinout, PCA2129T/Q900/2 application, or PCA2129T/Q900/2 equivalent, key selection considerations include AEC-Q100 qualification, dual I²C/SPI interface support, timestamp and watchdog interrupt capability, battery switch-over architecture, and factory-calibrated aging offset correction.
Technical Context
The PCA2129T/Q900/2 integrates a TCXO with on-die temperature sensor and programmable load capacitance switching to correct frequency drift across −40 °C to +85 °C. Its RTC core maintains BCD-encoded time/date registers with leap-year correction and supports 12-/24-hour mode via Control_1 register bit 2.
It implements two independent serial interfaces: a 400 kHz Fast-mode I²C-bus (SCL/SDA/INT) and a 3-line SPI-bus (SCL/SDI/SDO/CE/IFS) with up to 6.5 Mbit/s speed. Interface selection is hardware-configured via IFS pin level, and register access uses auto-incrementing addressing from 00h to 1Bh.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Accuracy | ±3 ppm over −30 °C to +80 °C - enables <1 s/day timing error in automotive cabin modules without external calibration. |
| Supply Voltage Range | 1.8 V to 4.2 V - compatible with wide-input automotive power rails and Li-ion backup batteries. |
| Quiescent Current | 0.70 μA typical at VDD = 3.3 V - extends 10-year battery life in smart meter applications. |
| Interface Options | Selectable I²C (400 kHz) or SPI (6.5 Mbit/s) - allows flexible host MCU integration without protocol translation. |
| Temperature Compensation | Factory-calibrated TCXO with OTP refresh - eliminates need for external compensation circuitry or firmware tuning. |
| Timestamp Function | Dual-event detection on TS pin with interrupt - supports tamper detection and power-fail logging in secure metering. |
| Aging Offset Correction | ±7 ppm adjustment range via Aging_offset register - compensates long-term crystal drift over 10+ year deployments. |
Pinout & Package
PCA2129T/Q900/2 is housed in a plastic small outline package (SO16) with 16 leads and 7.5 mm body width (SOT162-1), optimized for automotive PCB layouts requiring thermal stability and moisture resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SCL | Serial clock input | Shared clock for both I²C and SPI modes; must be pulled up externally for I²C operation. |
| SDI | SPI data input | Connected to VSS when I²C mode is selected; unused otherwise. |
| SDO | SPI data output | Push-pull output; high-impedance during battery backup to prevent backfeed. |
| SDA/CE | I²C data / SPI chip enable | Open-drain I²C bidirectional line; active-low CE for SPI mode selection. |
| IFS | Interface selector | Pulled to VSS for SPI; connected to BBS for I²C - determines bus protocol at power-up. |
| TS | Timestamp input | Active-low input with 200 kΩ internal pull-up; detects tamper or event edges for time-stamped logging. |
| CLKOUT | Programmable clock output | Open-drain output supporting 1 Hz to 32.768 kHz; disabled by COF=111 for lowest power. |
| INT | Interrupt output | Open-drain, active-low signal indicating alarm, watchdog timeout, timestamp, or battery events. |
| BBS | Battery-backed supply | Provides regulated Voper(int) voltage during main power loss; powers RTC core and registers. |
| VBAT | Battery supply input | Accepts 1.8–4.2 V backup source; internally monitored for low-voltage flag (BLF) generation. |
| VDD | Main supply input | Primary power rail; monitored against VBAT and Vth(sw)bat (2.5 V typ.) for switch-over decisions. |
| VSS | Ground reference | Common return for all analog/digital circuits; requires low-inductance decoupling near package. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 3 qualification | Validated for −40 °C to +85 °C operation - meets automotive electronics reliability requirements without derating. |
| Integrated TCXO + crystal | Eliminates external crystal, load capacitors, and compensation circuitry - reduces BOM count and layout area by ≥4 components. |
| Programmable watchdog timer | Four selectable clock sources yield timeout periods from <1 ms to >4 hours - enables robust system recovery in unattended devices. |
| Battery switch-over with timestamp | Records exact time of power failure transition in dedicated registers - supports forensic logging in utility meters and telematics. |
| Factory OTP calibration | One-time programmable memory stores individual TCXO coefficients - ensures ±3 ppm accuracy without field calibration. |
| Backup battery low detection | Dedicated BLF flag and interrupt - alerts host MCU before RTC data integrity is compromised by weak battery. |
Applications
| Smart Electricity Metering | Automotive Cabin Clock Module |
|---|---|
Use Scenario: Long-term energy billing with tamper-proof time stamping and power-loss resilience. IC Role / Device Role / Timing Role: Primary RTC providing accurate calendar, alarm-triggered metering cycles, and timestamped tamper events. Use Value: ±3 ppm accuracy ensures <1 s/month deviation over 10 years; battery switch-over preserves time during grid outages. |
Use Scenario: Infotainment system clock maintaining accurate time across ignition cycles and deep sleep states. IC Role / Device Role / Timing Role: Automotive-grade timekeeper with AEC-Q100 compliance, powering clock display and navigation time sync. Use Value: Integrated TCXO eliminates external crystal placement sensitivity; low 0.70 μA current extends battery backup life beyond 5 years. |
| GPS Time-to-First-Fix Acceleration | Industrial Process Timer |
Use Scenario: Reducing cold-start GPS acquisition time by providing precise UTC time to GNSS receiver. IC Role / Device Role / Timing Role: High-accuracy RTC supplying time-of-day and date to assist GPS almanac prediction. Use Value: 32.768 kHz CLKOUT enables direct oscillator feed to GPS module; ±3 ppm accuracy cuts TTFF by up to 40%. |
Use Scenario: Unattended factory equipment requiring scheduled maintenance alerts and process cycle timing. IC Role / Device Role / Timing Role: Standalone timing engine generating alarms, watchdog resets, and timestamped operational logs. Use Value: Programmable 1-second/1-minute interrupts drive PLC logic; aging offset register compensates for long-term drift in 15-year deployments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar RTC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Maxim MAX31343 | ±5 ppm accuracy over −40 °C to +85 °C; no integrated crystal; requires external TCXO or XTAL + load caps. | Lacks integrated TCXO and factory OTP calibration - demands additional board space and calibration effort. | Choose when lower cost outweighs accuracy and integration benefits; verify external crystal layout for ±5 ppm performance. |
| STMicroelectronics M41T83 | ±20 ppm accuracy; no temperature compensation; 5 V tolerant I²C; no SPI interface; no timestamp or aging correction. | Designed for legacy industrial systems where high accuracy and automotive qualification are not required. | Use only in non-automotive, cost-sensitive designs with relaxed timing specs and existing 5 V infrastructure. |
Compared with MAX31343 and M41T83, the PCA2129T/Q900/2 delivers superior accuracy and integration - its embedded TCXO, AEC-Q100 rating, and aging offset register make it uniquely suited for automotive and premium metering applications where long-term timing integrity is critical.
Availability
PCA2129T/Q900/2 is available at Aetrix Electronics and suitable for smart metering, automotive infotainment, GPS-assisted navigation, and industrial process timing requiring stable component supply across extended product lifecycles.
Supply support for PCA2129T/Q900/2 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
NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in mixed-signal timing and power management ICs.
The PCA2129T/Q900/2 belongs to NXP's automotive-qualified RTC product line, designed specifically for high-reliability timekeeping in safety-critical and long-lifecycle systems where accuracy, low power, and integration are mandatory.
FAQ
What is the operating temperature range for the PCA2129T/Q900/2?
The PCA2129T/Q900/2 is qualified per AEC-Q100 Grade 3 and operates reliably from −40 °C to +85 °C. Its integrated TCXO maintains ±3 ppm accuracy specifically between −30 °C and +80 °C, making it suitable for under-hood and cabin automotive environments as well as industrial metering enclosures.
Does the PCA2129T/Q900/2 require external crystals or load capacitors?
No. The PCA2129T/Q900/2 integrates both a 32.768 kHz quartz crystal and a temperature-compensated oscillator (TCXO) with factory-trimmed load capacitance inside the SO16 package. This eliminates the need for external crystals, trimming capacitors, or compensation circuitry - reducing design complexity and board area.
How does the battery switch-over function work in the PCA2129T/Q900/2?
The PCA2129T/Q900/2 monitors VDD against VBAT and a 2.5 V threshold (Vth(sw)bat) to trigger automatic switch-over. In standard mode, it switches when VDD < VBAT and VDD < 2.5 V; in direct mode, it switches whenever VDD < VBAT. The BF flag and optional timestamp record the event, and BBS supplies regulated voltage to preserve RTC operation.
Can the PCA2129T/Q900/2 generate a 1 Hz output for system wake-up?
Yes. The PCA2129T/Q900/2 supports programmable CLKOUT frequencies from 32.768 kHz down to 1 Hz via the COF[2:0] bits in register 0Fh. When configured for 1 Hz, CLKOUT provides a precise, low-jitter square wave ideal for microcontroller wake-up timers or LED blink control without external dividers.
What interfaces does the PCA2129T/Q900/2 support, and how are they selected?
The PCA2129T/Q900/2 supports both I²C (400 kHz Fast-mode) and SPI (up to 6.5 Mbit/s) interfaces. Selection is hardware-based: pulling IFS to VSS configures SPI mode; connecting IFS to BBS selects I²C mode. SDA/CE serves as bidirectional I²C data line or active-low SPI chip enable, enabling flexible host MCU compatibility.
PCA2129T/Q900/2,51 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, Leap Year, Square Wave Output, TCXO/Crystal, Watchdog Timer
- 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 ~ 4.2V
- Voltage - Supply, Battery:
- 1.8V ~ 4.2V
- Current - Timekeeping (Max):
- 1.5µA @ 3.3V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 16-SO
PCA2129T/Q900/2,51 FAQ
1.How can I place an order for PCA2129T/Q900/2,51 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA2129T/Q900/2,51 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 PCA2129T/Q900/2,51 reliable?
The price and inventory of PCA2129T/Q900/2,51 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA2129T/Q900/2,51 is usually 5 days.
3.What payment methods are accepted for PCA2129T/Q900/2,51?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA2129T/Q900/2,51 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA2129T/Q900/2,51?
PCA2129T/Q900/2,51 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA2129T/Q900/2,51 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 PCA2129T/Q900/2,51?
For technical support, including PCA2129T/Q900/2,51 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA2129T/Q900/2,51 requirements.
6.How does Aetrix verify that PCA2129T/Q900/2,51 is sourced from the original manufacturer or authorized distributors?
All PCA2129T/Q900/2,51 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 PCA2129T/Q900/2,51 meets industry standards.
7.What is the process for return or replacement of PCA2129T/Q900/2,51?
All PCA2129T/Q900/2,51 units undergo pre-shipment inspection (PSI). If there is an issue with PCA2129T/Q900/2,51, 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 PCA2129T/Q900/2,51 part is unused and in its original packaging.
Return procedure for PCA2129T/Q900/2,51:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
PCA2129T/Q900/2,51 Tags
-
MCP7940N-I/SN
Microchip Technology
-
MCP7940MT-I/MNY
Microchip Technology
-
PCF85063ATL/1,118
NXP USA Inc.
-
MCP7940NT-I/SN
Microchip Technology
-
MCP7940NT-I/MS
Microchip Technology
-
MCP7940N-I/MS
Microchip Technology
-
PCF85063AT/AY
NXP USA Inc.
-
PCF85063TP/1Z
NXP Semiconductors
-
PCF85063ATT/AJ
NXP USA Inc.
-
MCP7940NT-E/SN
Microchip Technology
-
MCP7940NT-I/MNY
Microchip Technology
-
MCP79400T-I/SN
Microchip Technology
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