component
MCP79400T-I
Public Made by Adomby adom
Microchip Tech Real Time Clocks, SOIC-8. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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Contents
README
markdownMCP79400T-I
Microchip Tech · Real Time Clocks · SOIC-8
MCP79400T-I from Microchip Tech, in a SOIC-8. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | X1 | input | Crystal oscillator input for a 32.768 kHz tuning-fork crystal with external load capacitors, optimized for crystals with 6-9 pF load capacitance; it also serves as the external clock input when the device is configured for an external oscillator. |
| 2 | X2 | output | Crystal oscillator output for the 32.768 kHz crystal; it must be left floating when an external 32.768 kHz clock is applied to X1. |
| 3 | VBAT | power_in | Backup supply input that maintains the RTCC and SRAM when VCC is unavailable; connect to VSS if battery backup is not used. |
| 4 | VSS | power_in | Ground reference for the device. |
| 5 | SDA | bidirectional | Open-drain bidirectional I2C serial data line that requires a pull-up resistor to VCC (typically 10 kΩ for 100 kHz or 2 kΩ for 400 kHz), and may change only while SCL is low except for Start and Stop conditions. |
| 6 | SCL | input | I2C serial clock input that synchronizes data transfer to and from the device. |
| 7 | MFP | output | Open-drain multifunction output for alarm, square-wave, or general-purpose output that requires a pull-up resistor to VCC (typically 10 kΩ) and may be left floating if unused. |
| 8 | VCC | power_in | Primary power supply input, with an operating voltage range of 1.8 V to 5.5 V as stated in the datasheet features list. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Microchip Tech |
| Package | SOIC-8 |
| Category | Clock/Timing |
| Pins | 8 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Supply voltage (VCC) absolute maximum | VCC | 6.5 | V | 3 | |||
| All inputs and outputs (except SDA and SCL) w.r.t. VSS | -0.6 | V | 3 | ||||
| SDA and SCL w.r.t. VSS | -0.6 | 6.5 | V | 3 | |||
| Storage temperature | -65 | 150 | °C | 3 | |||
| Ambient temperature with power applied | -40 | 125 | °C | 3 | |||
| ESD protection on all pins | 4 | kV | 3 | ||||
| Operating supply voltage range (Industrial) | VCC | 1.8 | 5.5 | V | Industrial (I) | 3 | |
| Operating ambient temperature range (Industrial) | TA | -40 | 85 | °C | Industrial (I) | 3 | |
| High-level input voltage (SDA, SCL) | VIH | 0.7 | ×VCC | 3 | |||
| Low-level input voltage (SDA, SCL) | VIL | 0.3 | ×VCC | VCC ≥ 2.5V | 3 | ||
| Low-level input voltage (SDA, SCL) | VIL | 0.2 | ×VCC | VCC < 2.5V | 3 | ||
| Hysteresis of Schmitt trigger inputs (SDA, SCL) | VHYS | 0.05 | ×VCC | Note 1 | 3 | ||
| Low-level output voltage (MFP, SDA) | VOL | 0.4 | V | IOL = 3.0 mA; VCC = 4.5V | 3 | ||
| Input leakage current | ILI | -1 | 1 | µA | VIN = VSS or VCC | 3 | |
| Output leakage current | ILO | -1 | 1 | µA | VOUT = VSS or VCC | 3 | |
| Pin capacitance (SDA, SCL, MFP) | CIN, COUT | 10 | pF | VCC = 5.0V (Note 1); TA = 25°C, f = 1 MHz | 3 | ||
| EEPROM operating current (read) | ICCEERD | 400 | µA | VCC = 5.5V, SCL = 400 kHz | 3 | ||
| EEPROM operating current (write) | ICCEEWR | 3 | mA | VCC = 5.5V | 3 | ||
| SRAM/RTCC register operating current (read) | ICCREAD | 300 | µA | VCC = 5.5V, SCL = 400 kHz | 3 | ||
| SRAM/RTCC register operating current (write) | ICCWRITE | 400 | µA | VCC = 5.5V, SCL = 400 kHz | 3 | ||
| VCC data-retention current (oscillator off) | ICCDAT | 1 | µA | SCL, SDA, VCC = 5.5V | 3 | ||
| Power-fail switchover voltage | VTRIP | 1.3 | 1.5 | 1.7 | V | 3 | |
| Backup supply voltage range | VBAT | 1.3 | 5.5 | V | Note 1 | 3 | |
| Timekeeping backup current | IBATT | 850 | nA | VBAT = 1.3V, VCC = VSS (Note 1) | 4 | ||
| Timekeeping backup current | IBATT | 925 | 1200 | nA | VBAT = 3.0V, VCC = VSS (Note 1) | 4 | |
| Timekeeping backup current | IBATT | 9000 | nA | VBAT = 5.5V, VCC = VSS (Note 1) | 4 | ||
| VBAT data-retention current (oscillator off) | IBATDAT | 750 | nA | VBAT = 3.6V, VCC = VSS | 4 | ||
| Clock frequency | FCLK | 100 | kHz | 1.8V ≤ VCC < 2.5V | 5 | ||
| Clock frequency | FCLK | 400 | kHz | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| Clock high time | THIGH | 4000 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| Clock high time | THIGH | 600 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| Clock low time | TLOW | 4700 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| Clock low time | TLOW | 1300 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| SDA and SCL rise time (Note 1) | TR | 1000 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| SDA and SCL rise time (Note 1) | TR | 300 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| SDA and SCL fall time (Note 1) | TF | 1000 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| SDA and SCL fall time (Note 1) | TF | 300 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| Start condition hold time | THD:STA | 4000 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| Start condition hold time | THD:STA | 600 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| Start condition setup time | TSU:STA | 4700 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| Start condition setup time | TSU:STA | 600 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| Data input hold time | THD:DAT | 0 | ns | Note 2 | 5 | ||
| Data input setup time | TSU:DAT | 250 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| Data input setup time | TSU:DAT | 100 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| Stop condition setup time | TSU:STO | 4000 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| Stop condition setup time | TSU:STO | 600 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| Output valid from clock | TAA | 3500 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| Output valid from clock | TAA | 900 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| Bus free time | TBUF | 4700 | ns | 1.8V ≤ VCC < 2.5V | 5 | ||
| Bus free time | TBUF | 1300 | ns | 2.5V ≤ VCC ≤ 5.5V | 5 | ||
| Input filter spike suppression (SDA and SCL) | TSP | 50 | ns | Note 1 | 5 | ||
| Write cycle time (byte or page) | TWC | 5 | ms | 5 | |||
| VCC fall time (Note 1) | TFVCC | 300 | µs | Note 1 | 5 | ||
| VCC rise time (Note 1) | TRVCC | 0 | µs | Note 1 | 5 | ||
| Oscillator timeout period (Note 1) | TOSF | 1 | ms | Note 1 | 5 | ||
| Pin capacitance (X1, X2 oscillator pins) | COSC | 3 | pF | Note 1 | 3 | ||
| Timekeeping current | ICCT | 1.2 | µA | VCC = 3.3V (Note 1) | 3 | ||
| Oscillator frequency | FOSC | 32.768 | kHz | 5 |
Materials and finish
As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).
| Part | Material | Colour / plating | Datasheet says | Page |
|---|---|---|---|---|
| contacts | tin | 8-Lead Plastic Small Outline (SN) - Narrow, 3.90 mm (.150 In.) Body [SOIC] A A2 | 44 |
CAD (KiCad official)
- Symbol:
MCP79400T-I - Footprint:
Package_SO:SOIC-8_3.9x4.9mm_P1.27mm - 3D model: SOIC-8 (KiCad packages3D, STEP)
- 3D model files:
mcp79400t-i-etched.step/mcp79400t-i-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);mcp79400t-i.step/mcp79400t-i.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Microchip Tech datasheet (60 pp, sha256
9dbb557d73a1b0be, retrieved 2026-10-21, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-sonnet-5-5(agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish. - CAD: KiCad official libraries (CC-BY-SA 4.0).