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MCP7940NT-I

Public Made by Adom

by adom

Microchip Real-time Clocks (RTC), SOIC-8. Pinout extracted from the datasheet, KiCad symbol/footprint/3D.

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Generated by kicad-footprint-generator · KiCad file format 20260206
Name Last commit message Last updated
docs mcp7940nt-i: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 3d ago
viewers pin 1: carry the footprint's marker into the .lbr, the viewer and page.json (silk-marker, drawn, top-left) · Ray 1mo ago
mcp7940nt-i-etched.fit.json mcp7940nt-i: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 3d ago
mcp7940nt-i-etched.glb mcp7940nt-i: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 3d ago
mcp7940nt-i-etched.step mcp7940nt-i: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 3d ago
mcp7940nt-i.glb Publish 0.1.0 · Ray 1mo ago
mcp7940nt-i.kicad_mod Publish 0.1.0 · Ray 1mo ago
mcp7940nt-i.kicad_sym Publish 0.1.0 · Ray 1mo ago
mcp7940nt-i.lbr rebuild the library on adom-lbr 2.32.0. The published copy was built by 2.18.0, which imported every KiCad roundrect and oval pad as a SQUARE EAGLE smd; this carries the real pad shape across (0 -> 8 rounded pads) and stops dropping geometry drawn on KiCad User.N layers. Attributes, connects, pads and the pin-1 marker are gated against decreasing and are unchanged. · Ray 1mo ago
mcp7940nt-i.step Publish 0.1.0 · Ray 1mo ago
package.json pin 1: carry the footprint's marker into the .lbr, the viewer and page.json (silk-marker, drawn, top-left) · Ray 1mo ago
pads.json page.json: drop the phantom "EP" pin. The datasheet package drawing is an 8-lead SOIC with 8 pads and no thermal pad, matching the shipped footprint exactly, so there is no exposed pad for this entry to describe and no symbol pin could ever resolve to it. Removed rather than "fixed" by adding a pad: putting copper under a part whose die has no thermal path would be the real defect. · Ray 1mo ago
page.json Brief states the pinout check that actually ran (was an unconditional "Datasheet-verified pinout") · Ray 12d ago
README.md mcp7940nt-i: laser-etched CAD + chip hero (factory 2.0.0 backfill) · Ray 17d ago

MCP7940NT-I

Microchip · Real-time Clocks (RTC) · SOIC-8

MCP7940NT-I from Microchip, 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 the 32.768 kHz tuning-fork crystal (optimized for 6-9 pF load capacitance) with its external load capacitor to VSS. Also usable as the external clock input when driving the device from an external oscillator.
2 X2 output Quartz crystal output. Connects to the second terminal of the 32.768 kHz crystal with its external load capacitor to VSS. Leave floating when using an external oscillator driving X1.
3 VBAT power_in Battery backup supply input, 1.3 V to 5.5 V. Maintains RTCC and SRAM when VCC is lost; typical timekeeping backup current is 925 nA at 3.0 V. Tie to VSS if the battery backup feature is not used.
4 VSS power_in Device ground (0 V) reference for VCC and VBAT rails and all logic signals.
5 SDA bidirectional Bidirectional I2C serial data (open-drain). Requires an external pull-up resistor to VCC (typ. 10 kΩ at 100 kHz or 2 kΩ at 400 kHz). Data may change only while SCL is low; changes while SCL is high signal Start/Stop conditions.
6 SCL input I2C serial clock input from the bus master, used to synchronize data transfer to/from the device. Supports clock rates up to 400 kHz. Schmitt-trigger input with 50 ns spike suppression; requires an external pull-up to VCC.
7 MFP output Multifunction output (open-drain). Configurable as alarm output on an alarm match, as a selectable-frequency square-wave output, or as a general-purpose output driven by the OUT bit in the CONTROL register. Requires an external pull-up resistor to VCC (typ. 10 kΩ); leave floating if unused. VOL = 0.40 V at IOL = 3.0 mA (VCC = 4.5 V).
8 VCC power_in Primary power supply, 1.8 V to 5.5 V. Typical timekeeping current 1.2 uA at 3.3 V; SRAM/RTCC register operating current is 300 uA (read) / 400 uA (write) at VCC = 5.5 V, SCL = 400 kHz. Power-fail switchover to VBAT occurs at VTRIP (1.3-1.7 V).
EP EP passive Exposed thermal/mechanical pad on the underside of the TDFN package. May be connected to VSS or left floating (per the Note under Table 3-1). Connection to VSS is recommended for mechanical anchoring and improved thermal performance.

Key specifications

Parameter Value
Manufacturer Microchip
Package SOIC-8
Category RTC
Pins 9

Ordering variants

Same part, different packaging or reel option.

  • MCP7940NT-IMNY
  • MCP7940NT-I/MNY
  • MCP7940NT-ISN
  • MCP7940NT-IMS
  • MCP7940NT-IST
  • MCP7940NT-IP

CAD (KiCad official)

  • Symbol: MCP7940NT-I
  • Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
  • 3D model: SOIC-8 (KiCad packages3D, STEP)
  • 3D model files: mcp7940nt-i-etched.step / mcp7940nt-i-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); mcp7940nt-i.step / mcp7940nt-i.glb are the bare package body.

Provenance

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

  • Datasheet: Microchip datasheet (56 pp, sha256 4aafe310fbafe313, retrieved 2026-08-17, tier: manufacturer)
  • 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