Microchip Technology MCP795W12-I/SL

Overview

MCP795W12-I/SL from Microchip Technology is a battery-backed SPI Real-Time Clock/Calendar (RTCC) IC with integrated watchdog timer, dual event detect modules, 64-byte SRAM, 1 Kbit EEPROM, and EUI-64™ MAC address storage. It delivers ±1 ppm digital trimming, power-fail timestamping, and 1.2 µA timekeeping current at 3.0V - enabling precise, low-power timekeeping in industrial metering and embedded control systems.

For engineers reviewing the MCP795W12-I/SL datasheet, MCP795W12-I/SL pinout, MCP795W12-I/SL application, or MCP795W12-I/SL equivalent, key selection criteria include its 14-pin SOIC/TSSOP package, 32.768 kHz crystal interface with 6–9 pF load optimization, dual programmable alarms, and SPI clock support up to 5 MHz for microcontroller co-designs.

Technical Context

The MCP795W12-I/SL implements a fully autonomous RTCC using an internal 32.768 kHz oscillator circuit with on-chip digital trimming (±259 ppm range, ±1 ppm resolution) and automatic switchover between VCC (1.8–3.6 V) and VBAT (1.3–3.6 V). Its SPI interface operates at up to 5 MHz with strict timing constraints including 100 ns CS setup time at 2.5–3.6 V.

It integrates two independent event detection paths: a high-speed input (EVHS) supporting programmable pulse counting, and a low-speed input (EVLS) with configurable debounce timing. The dedicated WDO and IRQ open-drain outputs support flexible interrupt routing for alarms, watchdog overflow, or event triggers.

Key Specifications

Pinout & Package

Package: 14-lead SOIC (MCP795W12-I/SL) and TSSOP - both RoHS-compliant, surface-mount, with 1.27 mm pitch and standard JEDEC outlines.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar real-time clock/calendar applications.

Compared with MCP795W11-I/SL, the MCP795W12-I/SL offers expanded network identity capability via EUI-64™, while DS3231M+ trades integrated peripherals for superior oscillator stability - making MCP795W12-I/SL optimal for resource-constrained, identity-aware embedded systems requiring robust timekeeping plus event awareness.

Availability

MCP795W12-I/SL is available at Aetrix Electronics and suitable for smart metering, industrial PLCs, medical infusion devices, and networked building sensors requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MCP795W12-I/SL 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

Microchip Technology Inc. is a leading provider of microcontrollers, analog components, and timing solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The MCP795Wxx family was designed to deliver highly integrated, low-power RTC functionality with enhanced system-level features - including watchdog, event detection, and secure identity - specifically for industrial, medical, and infrastructure applications demanding reliability and long service life.

FAQ

What is the primary function of the MCP795W12-I/SL?

The MCP795W12-I/SL is a battery-backed SPI Real-Time Clock/Calendar IC that maintains accurate time and date (including leap-year compensation through 2399), logs power-fail events, and provides integrated peripherals such as dual alarms, watchdog timer, and event detection. Its core function is autonomous, low-power timekeeping with system-level supervision capabilities - essential for applications where host MCU resources are constrained or unavailable during backup operation.

Does the MCP795W12-I/SL require external load capacitors for the 32.768 kHz crystal?

Yes, the MCP795W12-I/SL requires external load capacitors on X1 and X2 pins when using a 32.768 kHz tuning fork crystal. It is optimized for crystals with 6–9 pF specified load capacitance. Capacitor values must be selected to match the crystal's CL specification, accounting for board stray capacitance per Equation 5-1 in the datasheet. Omitting or mis-sizing these capacitors will degrade frequency accuracy and may prevent oscillation.

How does the power-fail timestamp feature work in the MCP795W12-I/SL?

The MCP795W12-I/SL automatically records the exact time of VCC loss (power-down timestamp) and VCC restoration (power-up timestamp) into dedicated register sets (PWRDNxxx and PWRUPxxx). This occurs during switchover between VCC and VBAT supplies at VTRIP ≈ 1.5 V. Timestamps are stored in BCD format and remain accessible over SPI even after recovery - enabling audit-compliant logging for energy meters, medical devices, and industrial controllers.

What memory resources are included in the MCP795W12-I/SL?

The MCP795W12-I/SL includes 64 bytes of battery-backed SRAM, 1 Kbit of software-write-protected EEPROM, and 128 bits of protected EEPROM preprogrammed with an EUI-64™ MAC address. SRAM and RTCC registers retain data during VCC loss. EEPROM supports page writes (up to 8 bytes), 1M erase/write cycles, and write-protection via status register. Protected EEPROM requires a robust unlock sequence before writes - ensuring secure storage of cryptographic keys or device identity.

Can the MCP795W12-I/SL operate with an external 32.768 kHz clock instead of a crystal?

Yes, the MCP795W12-I/SL supports external clock input mode: connect the 32.768 kHz signal to the X1 pin and set the EXTOSC bit in the CONTROL register. In this configuration, the X2 pin must be left floating. This bypasses the internal oscillator circuit and eliminates crystal load capacitor requirements - useful in systems where a clean, low-jitter clock is already available from another source, such as a microcontroller or system clock generator.