# Regional Salmon KITT
## Description
USB-C VBUS Integration with Onboard Li-ion Charger and Power-Path for Dual Laser Drivers
## Project Details
- **Owner:** golfsaber
- **Created:** 12/20/2025
- **Last Updated:** 12/20/2025
- **Visibility:** Public
- **PCB Layout Size:** 14.0 mm x 10.0 mm
- **System Architecture:** flowchart TD
MicroHeader --> PullDownResistors
PullDownResistors --> ESDTVSDiodes
ESDTVSDiodes --> RCNetwork
RCNetwork --> LiIonCharger
LiIonCharger --> PowerPathController
PowerPathController --> LaserDrivers
- **Power Requirements:** USB
- **Part Type:** Power Management
- **License:** https://www.gnu.org/licenses/gpl-3.0.html
- **Domain:** Consumer Electronics
- **Connectivity:** USB
## Key Components
### D1 — [ESD321DPYR](https://www.flux.ai/corvus96/esd321dpyr.md)
- Package: SMD_0402_1005Metric
- Manufacturer Name: Texas Instruments
- Diode Type: ESD
- Part Type: Diode
- Max Reverse Voltage: 5V
- Manufacturer Part Number: ESD321DPYR
- Datasheet URL: https://www.ti.com/lit/ds/symlink/esd321.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1690491326127&ref_url=https%253A%252F%252Fwww.ti.com%252Fgeneral%252Fdocs%252Fsuppproductinfo.tsp%253FdistId%253D10%2526gotoUrl%253Dhttps%253A%252F%252Fwww.ti.com%252Flit%252Fgpn%252Fesd321
- Role Details: ESD protection for USB D+ data line
- Role: Protection
**Pins:**
- GND [pin 2]
- IO [pin 1]
### D2 — [ESD321DPYR](https://www.flux.ai/corvus96/esd321dpyr.md)
- Max Reverse Voltage: 5V
- Diode Type: ESD
- Manufacturer Name: Texas Instruments
- Part Type: Diode
- Package: SMD_0402_1005Metric
- Role Details: ESD protection for USB D- data line
- Datasheet URL: https://www.ti.com/lit/ds/symlink/esd321.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1690491326127&ref_url=https%253A%252F%252Fwww.ti.com%252Fgeneral%252Fdocs%252Fsuppproductinfo.tsp%253FdistId%253D10%2526gotoUrl%253Dhttps%253A%252F%252Fwww.ti.com%252Flit%252Fgpn%252Fesd321
- Manufacturer Part Number: ESD321DPYR
- Role: Protection
**Pins:**
- GND [pin 2]
- IO [pin 1]
### J1 — [Pin Header 01x07 2.00mm Horizontal](https://www.flux.ai/adrian95/pin-header-01x07-200mm-horizontal.md)
- Connector Pitch: 2mm
- Connector Gender: Male
- Part Type: Connector
- Mount: Through Hole
- Connector Positions: 7
- Package or Case Code: PinHeader_1x07_P2.00mm_Horizontal
- License: https://creativecommons.org/licenses/by/4.0/
- Role Details: Micro header for USB-C harness interface (VBUS, GND, CC1, CC2, D+, D-, Shield)
- Role: Connector
- KiCAD Library Reference: PinHeader_1x07_P2.00mm_Horizontal
- Connector Rows: 1
- Connector Type: Headers and Wire Housings
**Pins:**
- Pin_1 [pin 1]
- Pin_2 [pin 2]
- Pin_3 [pin 3]
- Pin_4 [pin 4]
- Pin_5 [pin 5]
- Pin_6 [pin 6]
- Pin_7 [pin 7]
### U1 — [MCP73831T-5ACI/OT](https://www.flux.ai/adrian95/mcp73831t-5aciot.md)
- License: https://creativecommons.org/licenses/by/4.0/
- Role: Power Conversion
- Datasheet URL: https://ww1.microchip.com/downloads/en/DeviceDoc/MCP73831-Family-Data-Sheet-DS20001984H.pdf
- Package: SOT-23-5
- Part Type: Integrated Circuit
- Manufacturer Part Number: MCP73831T-5ACI/OT
- Manufacturer Name: Microchip Technology
- Role Details: Li-ion battery charger for USB VBUS input
**Pins:**
- PROG [pin 5]
- STAT [pin 1]
- VBAT [pin 3]
- VIN [pin 4]
- VSS [pin 2]
### U2 — [BQ24075TRGTR](https://www.flux.ai/adrian95/bq24075trgtr.md)
- Datasheet URL: http://componentsearchengine.com/Datasheets/1/BQ24075TRGTR.pdf
- Role Details: Power-path controller for SYS/BAT output
- Role: Power Path Management
- Package: QFN50P300X300X100-17N-D
- License: https://creativecommons.org/licenses/by/4.0/
- Package or Case Code: QFN50P300X300X100-17N-D
- Manufacturer Name: Texas Instruments
- Manufacturer Part Number: BQ24075TRGTR
- Part Type: Integrated Circuit
**Pins:**
- ~CE [pin 4]
- ~CHG [pin 9]
- ~PGOOD [pin 7]
- BAT_1 [pin 2]
- BAT_2 [pin 3]
- EN1 [pin 6]
- EN2 [pin 5]
- EP [pin 17]
- ILIM [pin 12]
- IN [pin 13]
- ISET [pin 16]
- OUT_1 [pin 10]
- OUT_2 [pin 11]
- SYSOFF [pin 15]
- TMR [pin 14]
- TS [pin 1]
- VSS [pin 8]
### U3 — [MAX3949ETE+T](https://www.flux.ai/lcsc/max3949eteplust.md)
- Part Type: Laser Drivers
- Manufacturer Part Number: MAX3949ETE+T
- Package: QFN-16_L3.0-W3.0-P0.50-TL-EP1.1
- JLCPCB Part Class: Extended Part
- Role Details: Dual laser diode driver for two laser diodes
- Role: Laser Drivers
- LCSC Part Number: C2988285
- Manufacturer Name: ADI(亚德诺)/MAXIM(美信)
- Package or Case Code: QFN-16_L3.0-W3.0-P0.50-TL-EP1.1
**Pins:**
- BIAS [pin 9]
- BMON [pin 4]
- CSEL [pin 10]
- DISABLE [pin 1]
- EP [pin 17]
- FAULT [pin 3]
- SCL [pin 12]
- SDA [pin 11]
- TIN- [pin 15]
- TIN+ [pin 14]
- TOUT- [pin 6]
- TOUT+ [pin 7]
- VCC [pin 13]
- VCC [pin 16]
- VCCT [pin 8]
- VCCT [pin 5]
- VSEL [pin 2]
*The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/golfsaber/regional-salmon-kitt](https://www.flux.ai/golfsaber/regional-salmon-kitt).*
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