component

MCP7940N-I

Public Unreviewed

by Ray

Microchip Tech Real Time Clocks, SOIC-8. Datasheet-verified pinout, KiCad symbol/footprint/3D.

componentclock-timingmcp7940n-i
Overview Files Discover Packages Releases Dependencies Issues Breadcrumbs Pull Requests Activity

3D Model

Open in new tab ↗
Loads on click. Unloads when scrolled away or the tab is hidden.

Symbol & Footprint

Schematic Symbol

Open full view ↗
Loads on click. Unloads when scrolled away or the tab is hidden.

PCB Footprint

Open full view ↗
Loads on click. Unloads when scrolled away or the tab is hidden.

Datasheet

Open in new tab ↗
Loads on click. Unloads when scrolled away or the tab is hidden.
Download PDF
Contents

README

markdown

MCP7940N-I

Microchip Tech · Real Time Clocks · SOIC-8

MCP7940N-I from Microchip Tech, in a SOIC-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 X1 input Quartz crystal input / external oscillator input. Connects to one terminal of a 32.768 kHz tuning-fork crystal (optimized for 6-9 pF load caps) or accepts an external clock when the device is configured for external oscillator mode.
2 X2 output Quartz crystal output. Drives the second terminal of the 32.768 kHz crystal (with external load capacitor). Unused when driving X1 from an external clock source.
3 VBAT power_in Battery backup supply input (1.3 V to 5.5 V). Maintains RTCC and SRAM operation when VCC is below the power-fail trip voltage (VTRIP typ. 1.5 V). Tie to VSS if battery backup is not used.
4 VSS power_in Ground / device negative supply reference (0 V).
5 SDA bidirectional I2C bidirectional serial data. Open-drain terminal; requires an external pull-up to VCC (typ. 10 kΩ at 100 kHz, 2 kΩ at 400 kHz). Data must be stable while SCL is high.
6 SCL input I2C serial clock input. Synchronizes data transfer to and from the device; supports up to 400 kHz.
7 MFP output Multifunction output pin. Configurable as an alarm-match output, a selectable-frequency square-wave output, or a general-purpose output driven by the CONTROL register OUT bit. Open-drain; requires an external pull-up to VCC (typ. 10 kΩ). May be left floating if unused.
8 VCC power_in Primary power supply (1.8 V to 5.5 V). Absolute maximum 6.5 V. Typical timekeeping current 1.2 µA at 3.3 V; SRAM/RTCC operating current up to 400 µA at 400 kHz SCL.

Key specifications

Parameter Value
Manufacturer Microchip Tech
Package SOIC-8
Category Clock/Timing
Pins 8

Ordering variants

Same part, different packaging or reel option.

  • MCP7940N-II/SN
  • MCP7940N-II/MS
  • MCP7940N-II/ST
  • MCP7940N-II/P
  • MCP7940N-II/MNY

CAD (KiCad official)

  • Symbol: MCP7940N-I
  • Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
  • 3D model: SOIC-8 (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Microchip Tech datasheet (56 pp, sha256 4aafe310fbafe313, retrieved 2026-08-17, tier: lcsc)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF