RX8900CE - DTCXO RTC I2C 10-SMD | Epson | TCXO
Référence : RX8900CE ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $3.63 | $3,63 |
| 10 | $3.2 | $32,00 |
| 100 | $2.55 | $255,00 |
| 500 | $2.18 | $1 090,00 |
| 1 000 | $1.92 | $1 920,00 |
RX8900CE Présentation
A Real-Time Clock (RTC) is a low-power integrated circuit that maintains accurate wall-clock time (seconds, minutes, hours, days, date, month, year) even when the host system is powered off, typically backed by a battery or supercapacitor. RTCs fall within the broader category of clock/calendar ICs, themselves a subset of power management and timing components. By integrating a TCXO and the crystal into one SMD module, the RX8900CE eliminates the need for an external 32.768 kHz quartz and the associated load-capacitor design trade-offs, simplifying layout and BOM.
Key features include ±5.0 ppm frequency stability over temperature, integrated 32.768 kHz DTCXO with on-chip crystal, an automatic power-switching circuit that seamlessly transitions between primary VDD and backup battery, two user-programmable alarm / time-update interrupts, and an I2C-bus interface (400 kHz Fast Mode compatible). Additional functions include a 32.768 kHz output pin for clocking an external MCU, century bit for dates beyond 2099, and a 12/24 hour timekeeping mode.
Internally the device uses a 32.768 kHz AT-cut crystal in conjunction with a fractional-N DTCXO compensation loop. The compensation register is trimmed during factory calibration to suppress the parabolic frequency-temperature curve, leaving a residual error dominated by linear slope. This architecture delivers near-OCXO accuracy in a module that costs and consumes roughly the same as an uncompensated RTC.
Typical applications include industrial IoT gateways and data loggers, metering and smart-grid endpoints, automotive infotainment and telematics requiring wide-temp accuracy, security/alarm panels with battery backup, and consumer electronics that must retain time during power loss. The wide -40 °C to +85 °C operating range makes it a strong fit for outdoor and automotive-grade designs.
When designing with the RX8900CE, ensure the backup battery is sized so that the VDD-to-BAT switchover voltage (typical 2.2 V) is not crossed during a normal power cycle. Decoupling must include a 0.1 µF ceramic close to VDD; the integrated crystal removes the need for external load capacitors but the I2C bus still requires pull-ups. Allow the TCXO ~2 s after VDD restoration to deliver its full accuracy.
This page synthesizes distributor pricing, drop-in alternatives within the same Epson RX-89xx family, and practical design notes that are not consolidated in the manufacturer datasheet.
Alternatives de remplacement direct pour RX8900CE — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
RX8901CE:UB0
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
RX8900CE:UB3
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
RX8900CE:UB6
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
RX8900CE:UBB
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
RX8901CE:UB3
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
RX8900CE Spécifications
| Fonction | Real-Time Clock with DTCXO |
| Interface | I2C (Fast Mode 400 kHz) |
| Time Format | HH:MM:SS / YY-MM-DD-DD, 12/24 hour |
| Supply Voltage (VDD) | 1.6 V to 5.5 V |
| Backup Supply (VBAT) | 1.6 V to 5.5 V (auto switchover) |
| Frequency Tolerance | ±5.0 ppm (typ., -40 °C to +85 °C) |
| Internal Oscillator | 32.768 kHz TCXO, on-chip crystal |
| Température de fonctionnement | -40 °C to +85 °C |
| Boîtier | 10-pin SMD, No Lead (10-SMD, CDCC10) |
| Type de montage | Surface Mount |
| Interrupt Outputs | 2 (alarm / time update, selectable) |
| 32 kHz Output | Yes (CLKOE-controlled) |
| I2C Address | 0x32 (I2C_SEL floating) / 0x32 selectable |
| Battery Switchover | Internal MOSFET, automatic |
| AEC-Q100 | Not qualified (industrial / consumer grade) |
| Statut RoHS | Compliant |
Configuration des broches de RX8900CE
| Broche 1 | VDD — Primary supply voltage (1.6 V to 5.5 V) |
| Broche 2 | VBAT (BACKUP) — Backup supply input; auto switchover when VDD < VBAT |
| Broche 3 | GND — Ground |
| Broche 4 | CLKOE — 32.768 kHz output enable (active high) |
| Broche 5 | FOUT — 32.768 kHz clock output (when CLKOE high) |
| Broche 6 | INTA — Interrupt A output (alarm / time-update, open-drain) |
| Broche 7 | SCL — I2C serial clock (requires external pull-up) |
| Broche 8 | SDA — I2C serial data (requires external pull-up) |
| Broche 9 | I2C_SEL — I2C address select |
| Broche 10 | N.C. — Not connected (per datasheet) |
Applications typiques
RX8900CE convient pour 6 applications: Industrial IoT Gateways and Data Loggers, Smart Metering and Smart-Grid Endpoints, Automotive Infotainment and Telematics (Non-Safety), Security and Alarm Panels with Battery Backup, Consumer Electronics with Time Retention, Outdoor Wireless Sensor Networks.
Industrial IoT Gateways and Data Loggers
The Epson RX8900CE delivers ±5.0 ppm accuracy across -40 °C to +85 °C without external crystal, making it a strong fit for industrial IoT gateways and remote data loggers that must timestamp events during cold winters or hot rooftop installs. With I2C addressing at 0x32 and Fast-Mode 400 kHz capability, the RX8900CE talks to low-power Cortex-M gateways over a two-wire bus, leaving GPIO for sensors. The integrated battery switchover preserves wall-clock time across power outages at metering cabinets, while the 32 kHz FOUT pin can drive the host MCU's RTC domain for sub-second synchronization. Compared to uncompensated RTCs that drift 10-20 ppm outdoors, the RX8900CE keeps timestamps within ~2 minutes per year, sufficient for most fleet-telematics and energy-metering audits.
Recommandé
Smart Metering and Smart-Grid Endpoints
Smart electricity, water, and gas meters require absolute time-of-use stamps for billing reconciliation across a 15-minute or 30-minute tariff window. The RX8900CE's ±5.0 ppm (-40 °C to +85 °C) accuracy keeps TOU drift under 2 minutes per year, satisfying IEC 62056-21 metering audit windows without field re-synchronization. The integrated crystal removes BOM and the wide 1.6 V-5.5 V range supports both lithium primary cells and supercapacitor backup rails used in AMI endpoints. The two interrupt outputs let the host wake only on alarm or 1-Hz tick, allowing the metering SoC to sleep most of the day, and the automatic VBAT switchover guarantees billing continuity through grid brownouts.
Recommandé
Automotive Infotainment and Telematics (Non-Safety)
Within non-safety automotive subsystems such as infotainment head units, telematics control units (TCUs), and eCall modules, the RX8900CE provides robust timekeeping across the vehicle's -40 °C to +85 °C cabin environment. Its I2C interface plugs directly into vehicle SoCs, while the integrated 32.768 kHz crystal simplifies the BOM in space-constrained dash modules. Note that the RX8900CE is NOT AEC-Q100 qualified, so it must remain in cabin-grade subsystems and not be used in safety-critical ECUs. For under-hood or engine-control timekeeping, designers should select an AEC-Q100 qualified Epson RTC such as the RA8900CE family instead.
Recommandé
Security and Alarm Panels with Battery Backup
Intrusion alarm panels and access-control systems must retain correct time and date through extended AC-power outages so that event logs survive forensic review. The RX8900CE's automatic VBAT switchover routes a CR2032 or supercapacitor source to the RTC core within microseconds of VDD dropout, while its ±5 ppm accuracy prevents log drift during multi-year backup. The two alarm interrupts can drive piezo buzzers or tamper-detection routines directly, and the integrated 32.768 kHz output lets a low-power MCU maintain its own calendar during deep sleep. The 1.6 V-5.5 V supply range also supports 3.3 V or 5 V host rails common in legacy alarm hardware.
Recommandé
Consumer Electronics with Time Retention
Appliances such as smart thermostats, washing machines, ovens, and rice cookers rely on accurate time-of-day and timer displays that survive power-down. The RX8900CE's on-chip TCXO and integrated crystal keep timer accuracy inside ±2 minutes per year even in hot laundry rooms or cold garages, while its small 10-pin SMD footprint fits tightly inside display modules. Designers can omit an external 32 kHz resonator and its load-capacitor tuning, reducing BOM cost by 30-50 cents per unit. The I2C address of 0x32 allows multiple devices on the same bus, simplifying firmware on single-master household appliances.
Recommandé
Outdoor Wireless Sensor Networks
LoRaWAN, NB-IoT, and Sub-GHz mesh sensors installed on streetlights, parking meters, and agricultural field nodes need RTC accuracy that survives year-round outdoor thermal swings. The RX8900CE's ±5 ppm tolerance from -40 °C to +85 °C means time-stamped packets remain legally traceable across multi-year deployments, and its integrated DTCXO removes the need for a tuning network that drifts over time. The 32 kHz output can clock the Sub-GHz radio's MAC layer for IEEE 802.15.4g synchronization, while the alarm interrupt wakes the host only on scheduled uplink slots. Battery switchover supports lithium-thionyl-chloride cells typical in 10-year outdoor sensor designs.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour RX8900CE — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | RX8901CE:UB0 | RX8900CE:UB3 | RX8900CE:UB6 | RX8900CE:UBB | RX8901CE:UB3 |
|---|---|---|---|---|---|---|
| Package | 10-pin SMD (CDCC10) | 10-pin SMD (CDCC10) - same | 10-pin SMD (CDCC10) - same | 10-pin SMD (CDCC10) - same | 10-pin SMD (CDCC10) - same | 10-pin SMD (CDCC10) - same |
| Brand | Epson | Epson - same | Epson - same | Epson - same | Epson - same | Epson - same |
| Frequency Tolerance (-40 to +85 °C) | ±5.0 ppm | ±3.0 ppm | ±5.0 ppm | ±5.0 ppm | ±5.0 ppm | ±3.0 ppm |
| Interface | I2C (400 kHz) | I2C (400 kHz) | I2C (400 kHz) | I2C (400 kHz) | I2C (400 kHz) | I2C (400 kHz) |
| Supply Voltage Range | 1.6 V to 5.5 V | 1.6 V to 5.5 V | 1.6 V to 5.5 V | 1.6 V to 5.5 V | 1.6 V to 5.5 V | 1.6 V to 5.5 V |
| Backup Switchover | Internal MOSFET | Internal MOSFET | Internal MOSFET | Internal MOSFET | Internal MOSFET | Internal MOSFET |
| 32 kHz Output | Yes (CLKOE-controlled) | Yes (CLKOE-controlled) | Yes (CLKOE-controlled) | Yes (CLKOE-controlled) | Yes (CLKOE-controlled) | Yes (CLKOE-controlled) |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
| I2C Address | 0x32 (default) | 0x32 (default) | 0x32 (default) | 0x32 (default) | 0x32 (default) | 0x32 (default) |
Principaux différenciateurs
- Integrated DTCXO inside the SMD package removes external crystal (vs NXP PCF85263A)
- Upgrade path to ±3.0 ppm without PCB change (vs Epson RX8901CE:UB0)
- I2C variant versus SPI sibling on the same 10-pin SMD footprint (vs Epson RX8900SA)
Notes de conception
The RX8900CE's internal power-switching MOSFET automatically routes the higher of VDD and VBAT to the RTC core, but designers must size the backup source so its loaded voltage never falls below 1.6 V. A CR2032 (~220 mAh) typically supports the RX8900CE for >5 years of pure backup, but heavy use of the INTA pull-up or 32 kHz output during backup will shorten that figure considerably. Place a 0.1 µF ceramic capacitor on VDD within 3 mm of the pin and a 0.1 µF ceramic on VBAT to suppress switchover transients.
Because the RX8900CE integrates the 32.768 kHz crystal, no external resonator or load capacitors are required. However, place the device away from heat sources (DC-DC inductors, MOSFETs) and avoid routing high-frequency digital or switching signals directly under the SMD footprint - thermal gradients and EMI coupling degrade TCXO accuracy. Keep I2C SDA/SCL traces short, add 4.7 kΩ pull-ups to VDD, and route them as a differential pair or at least length-matched if the bus length exceeds 50 mm.
Three pitfalls to avoid when bringing up the RX8900CE: (1) failing to write 0x00 to the VL-bit / Voltage-Low flag register after first power-up - this will leave the RTC thinking it just experienced a brownout; (2) neglecting the 2-second TCXO stabilization after VDD rises above 1.6 V - read the time registers before stabilization and you'll see a 'frozen' timestamp; (3) tying INTA to a push-pull GPIO - INTA is open-drain and MUST have a pull-up to VDD or it will never flag an alarm interrupt.
Informations de conformité
RoHS and REACH compliant per Epson product page; lead-free reflow profile per JEDEC J-STD-020. NOT AEC-Q100 qualified - use the Epson RA8900CE family for automotive safety-critical subsystems.
