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NXP Semiconductors PCF2123U/12HA/1,00
- Part No.:
- PCF2123U/12HA/1,00
- Manufacturer:
- NXP Semiconductors
- Category:
- Real Time Clocks
- Package:
- Die
- Datasheet:
-
PCF2123U/12HA/1,00.pdf
- Description:
- IC RTC CLOCK/CALENDAR SPI DIE
- Quantity:
- Payment:
- Shipping:
Inventory:1,550
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Product details
Overview
PCF2123U/12HA/1,00 from NXP Semiconductors is a wafer-level chip-scale packaged (WLCSP12) SPI real-time clock/calendar IC with integrated 32.768 kHz oscillator, programmable alarm/timer, and 100 nA typical backup current at 2.0 V. It delivers BCD-encoded timekeeping from seconds to years, supports 1.1–5.5 V operation, and generates open-drain interrupt signals for wake-up in battery-powered metering and low-standby systems.
For engineers reviewing the PCF2123U/12HA/1,00 datasheet, PCF2123U/12HA/1,00 pinout, PCF2123U/12HA/1,00 application, or PCF2123U/12HA/1,00 equivalent, this page provides verified functional specifications, WLCSP12 terminal mapping, low-power design trade-offs, and validated alternative RTCs for time-critical embedded systems requiring long-duration battery operation and precise calendar functionality.
Technical Context
The PCF2123U/12HA/1,00 implements a fully autonomous RTC core with on-die 32.768 kHz oscillator and integrated 7 pF load capacitors, eliminating external crystal tuning components. Its 16-register memory map includes BCD-coded time/date registers (02h–08h), alarm registers (09h–0Ch), offset calibration (0Dh), and timer control (0Eh–0Fh), all accessible via 3-wire SPI up to 6.25 Mbit/s.
It features dual interrupt capability: one driven by alarm matches (AF flag + AIE enable), another by pre-defined 1-second or 1-minute intervals (SI/MI bits), both routed to the open-drain INT pin. The STOP bit in Control_1 (00h) halts RTC counting while preserving CLKOUT frequency options, and the OS flag in Seconds register (02h) provides hardware-observable oscillator health monitoring.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Interface | SPI-bus (3-line: CE, SCL, SDI/SDO); 6.25 Mbit/s max - enables fast host synchronization without I²C pull-up constraints |
| Time Resolution | Seconds to years in BCD format - eliminates software BCD conversion overhead in microcontroller firmware |
| Backup Current | 100 nA typical at VDD = 2.0 V, Tamb = 25 °C - extends coin-cell life beyond 10 years in always-on applications |
| Operating Voltage | 1.1 V to 5.5 V - supports direct connection to Li-ion, alkaline, or regulated 1.8/3.3 V rails without level-shifting |
| Oscillator | Integrated 32.768 kHz with CL = 7 pF - removes need for external load capacitors and reduces board area by ≥2 mm² |
| Interrupt Outputs | Open-drain INT and CLKOUT pins - allows wired-OR sharing with other peripherals and flexible voltage-domain interfacing |
| Timer Sources | Four selectable clocks: 4.096 kHz, 64 Hz, 1 Hz, 1/60 Hz - enables precision timing from 244 µs to 4.25 hours with minimal power penalty |
Pinout & Package
PCF2123U/12HA/1,00 is supplied in a 12-bump wafer-level chip-scale package (WLCSP12), measuring 1.63 × 1.63 × 0.52 mm, designed for direct die attach or flip-chip integration into space-constrained modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SDO | Serial Data Output | Push-pull output; high-impedance when inactive - permits single-wire SPI bus sharing with SDI |
| SDI | Serial Data Input | CMOS input; floats when CE is low - reduces standby leakage in idle host communication states |
| SCL | Serial Clock Input | Edge-triggered input; floats when CE inactive - decouples clock domain during SPI idle periods |
| CE | Chip Enable | Active-HIGH with internal pull-down - ensures default SPI disable at power-up and prevents spurious writes |
| INT | Interrupt Output | Open-drain, active-LOW - supports multi-source interrupt aggregation and level translation to 1.2–5 V logic |
| CLKOUT | Clock Output | Open-drain, configurable frequency - provides system clock reference or sleep-wake timing signal |
| CLKOE | CLKOUT Enable | Active-HIGH control - allows dynamic CLKOUT gating to reduce system EMI and power during deep sleep |
| OSCI / OSCO | Oscillator Input/Output | High-impedance nodes; require minimal trace length - ensures stable 32.768 kHz oscillation with low Rs quartz |
| VDD / VSS | Power Supply / Ground | Single-supply operation; 100 nF decoupling recommended near VDD - maintains oscillator stability under transient loads |
| TEST | Factory Test Pin | Internally pulled down; not user-accessible - must be tied to VSS or left floating per datasheet guidance |
Key Features
| Feature | Design Value |
|---|---|
| On-die oscillator with 7 pF load caps | Eliminates two external 12 pF capacitors and associated layout sensitivity, reducing component count and footprint |
| Programmable offset register (0Dh) | Enables ±127 ppm fine-tuning of 32.768 kHz frequency to compensate for crystal aging and temperature drift |
| OS flag in Seconds register (02h) | Hardware-monitored oscillator status bit - allows firmware to detect and recover from crystal failure or VDD brownout |
| Auto-incrementing address counter | Enables atomic read/write of time registers (02h–08h) in single SPI transaction - prevents time corruption during carry events |
| Watchdog functionality | Integrated monitor circuit triggers reset if host fails to service periodic timer interrupts - enhances system reliability in unattended devices |
Applications
| Metering Systems | Battery-Powered IoT Sensors |
|---|---|
Use Scenario: Smart water/gas meters logging consumption every 15 minutes with tamper detection and last-gasp reporting. IC Role / Device Role / Timing Role: Primary RTC providing timestamped event records, calendar-based billing cycles, and wake-up for periodic radio transmission. Use Value: 100 nA backup current enables >10-year coin-cell operation; integrated oscillator ensures timing accuracy without external tuning parts. |
Use Scenario: Wireless environmental sensors deployed in remote locations, transmitting temperature/humidity hourly using BLE or LoRaWAN. IC Role / Device Role / Timing Role: Low-power timekeeper enabling scheduled deep-sleep wake-ups, calendar-aware data logging, and alarm-driven emergency alerts. Use Value: Programmable 1-minute/1-second interrupts eliminate MCU polling; WLCSP12 package fits within <2 mm² PCB area budget. |
| Industrial Control Panels | Medical Wearables |
Use Scenario: Human-machine interface (HMI) panels requiring accurate timestamping of operator actions, maintenance logs, and firmware update scheduling. IC Role / Device Role / Timing Role: System-level calendar and alarm engine synchronizing UI refreshes, audit trails, and scheduled diagnostics. Use Value: BCD-encoded registers simplify firmware integration; alarm function triggers maintenance reminders without CPU intervention. |
Use Scenario: Continuous glucose monitors (CGMs) or ECG patches recording physiological data at fixed intervals and alerting users on schedule. IC Role / Device Role / Timing Role: Precision timebase for sensor sampling, therapy timers, and patient alarm generation (e.g., "take medication at 08:00"). Use Value: 1.1 V minimum operating voltage supports direct connection to discharged LiPo cells; open-drain INT pin interfaces safely with ultra-low-voltage MCUs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar real-time clock applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS3231M | Integrated TCXO (±2 ppm accuracy), I²C interface, higher 1.5 µA backup current | Superior accuracy in wide-temperature industrial environments; requires I²C pull-ups and external crystal compensation | Choose DS3231M when ±2 ppm accuracy across –40°C to +85°C is mandatory and I²C is preferred over SPI |
| RV-3028-C7 | Ultra-low 150 nA backup current, I²C/SPI dual interface, no integrated load caps | Lower power than PCF2123U/12HA/1,00 but requires external 12.5 pF capacitors and lacks watchdog function | Choose RV-3028-C7 when minimizing nanoampere standby dominates over oscillator integration and system supervision |
Compared with DS3231M and RV-3028-C7, PCF2123U/12HA/1,00 uniquely combines SPI interface, integrated 7 pF load capacitors, and hardware watchdog in a WLCSP12 package-making it optimal for cost-sensitive, space-constrained, battery-operated designs where ±20 ppm accuracy suffices and SPI host architecture is fixed.
Availability
PCF2123U/12HA/1,00 is available at Aetrix Electronics and suitable for metering systems, battery-powered IoT sensors, and industrial control panels requiring stable component supply, long-term lifecycle support, and wafer-level packaging for miniaturized assemblies.
Supply support for PCF2123U/12HA/1,00 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 markets, with deep expertise in low-power mixed-signal design and embedded security.
The PCF2123 product line delivers highly integrated, ultra-low-power RTCs targeting battery-backed applications where size, longevity, and autonomous timekeeping are critical-especially in utility metering, portable medical devices, and asset tracking.
FAQ
What is the package type and dimensions of PCF2123U/12HA/1,00?
PCF2123U/12HA/1,00 uses a wafer-level chip-scale package (WLCSP12) with 12 bumps, measuring 1.63 mm × 1.63 mm × 0.52 mm. This bare-die form factor is intended for direct die attach or flip-chip assembly in ultra-compact modules, and differs from the HVQFN16 and TSSOP14 variants of the same PCF2123 family.
Does PCF2123U/12HA/1,00 require external load capacitors for the 32.768 kHz crystal?
No. PCF2123U/12HA/1,00 integrates optimized 7 pF load capacitors internally, eliminating the need for external capacitors. This reduces bill-of-materials cost and PCB area, and improves oscillator stability by removing parasitic trace capacitance variables-confirmed in Section 7.2 and Figure 1 of the official NXP datasheet.
How does the OS (Oscillator Stop) flag in PCF2123U/12HA/1,00 improve system reliability?
The OS flag (bit 7 of Seconds register 02h) is automatically set when the 32.768 kHz oscillator stops due to crystal fault, excessive series resistance, or VDD drop below threshold. Firmware can poll this flag at startup or periodically to validate time integrity-ensuring PCF2123U/12HA/1,00 only reports valid timestamps after confirmed oscillator stability.
Can PCF2123U/12HA/1,00 generate both alarm and periodic interrupts simultaneously?
Yes. PCF2123U/12HA/1,00 supports concurrent alarm-triggered interrupts (via AF flag + AIE enable) and periodic 1-second or 1-minute interrupts (via SI/MI bits in Control_2 register 01h). Both assert the same open-drain INT pin, so firmware must read Control_2 to distinguish source-enabling efficient wake-up handling for multiple timing events.
What is the maximum SPI clock frequency supported by PCF2123U/12HA/1,00?
PCF2123U/12HA/1,00 supports SPI communication up to 6.25 Mbit/s, as specified in the General Description and Functional Description sections of the NXP datasheet. This high-speed interface enables rapid time/calendar register reads/writes and minimizes host MCU active time-critical for optimizing overall system power in battery-operated designs.
PCF2123U/12HA/1,00 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- Die
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, Leap Year, Square Wave Output, Watchdog Timer
- Memory Size:
- -
- Time Format:
- HH:MM:SS (12/24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- SPI
- Voltage - Supply:
- 1.6V ~ 5.5V
- Voltage - Supply, Battery:
- -
- Current - Timekeeping (Max):
- 0.33µA ~ 0.38µA @ 2V ~ 5V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- -
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- Die
PCF2123U/12HA/1,00 FAQ
1.How can I place an order for PCF2123U/12HA/1,00 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCF2123U/12HA/1,00 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 PCF2123U/12HA/1,00 reliable?
The price and inventory of PCF2123U/12HA/1,00 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCF2123U/12HA/1,00 is usually 5 days.
3.What payment methods are accepted for PCF2123U/12HA/1,00?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCF2123U/12HA/1,00 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCF2123U/12HA/1,00?
PCF2123U/12HA/1,00 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCF2123U/12HA/1,00 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 PCF2123U/12HA/1,00?
For technical support, including PCF2123U/12HA/1,00 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCF2123U/12HA/1,00 requirements.
6.How does Aetrix verify that PCF2123U/12HA/1,00 is sourced from the original manufacturer or authorized distributors?
All PCF2123U/12HA/1,00 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 PCF2123U/12HA/1,00 meets industry standards.
7.What is the process for return or replacement of PCF2123U/12HA/1,00?
All PCF2123U/12HA/1,00 units undergo pre-shipment inspection (PSI). If there is an issue with PCF2123U/12HA/1,00, 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 PCF2123U/12HA/1,00 part is unused and in its original packaging.
Return procedure for PCF2123U/12HA/1,00:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
PCF2123U/12HA/1,00 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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