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UM823SS

Public Made by Adom

by adom

Union Semiconductor Supervisor and Reset ICs, SOT-23-5. 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 um823ss: 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
package.json Publish 0.2.0 · Ray 1mo ago
pads.json pin 1: carry the footprint's marker into the .lbr, the viewer and page.json (silk-marker, drawn, top-left) · Ray 1mo ago
page.json Brief states the pinout check that actually ran (was an unconditional "Datasheet-verified pinout") · Ray 10d ago
README.md um823ss: laser-etched CAD + chip hero (factory 2.0.0 backfill) · Ray 14d ago
um823ss-etched.fit.json um823ss: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 3d ago
um823ss-etched.glb um823ss: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 3d ago
um823ss-etched.step um823ss: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 3d ago
um823ss.glb Publish 0.1.0 · Ray 1mo ago
um823ss.kicad_mod Publish 0.1.0 · Ray 1mo ago
um823ss.kicad_sym Publish 0.1.0 · Ray 1mo ago
um823ss.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 -> 5 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
um823ss.step Publish 0.1.0 · Ray 1mo ago

UM823SS

Union Semiconductor · Supervisor and Reset ICs · SOT-23-5

UM823SS from Union Semiconductor, in a SOT-23-5. 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 RESET output Active-low reset output. Pulses low for 200ms (tRP) when triggered and remains low whenever VCC is below the 2.93V reset threshold or when MR is a logic low. Guaranteed valid down to VCC=1V. VOL<=0.3V @ 4mA sink; VOH>=0.8*VCC @ 1mA source.
2 GND power_in Ground reference for all signals.
3 MR input Manual-Reset Input (active low). Triggers a reset pulse when pulled below 0.3*VCC. Has an internal ~52kΩ pull-up resistor; can be driven from TTL/CMOS logic or shorted to GND with a switch. Leave open or tie to VCC if unused.
4 WDI input Watchdog Input. If WDI stays high or low for longer than the watchdog timeout period (1.6s typical), the internal watchdog timer expires and a reset is triggered. The timer clears whenever RESET is asserted or WDI sees a rising or falling edge (min pulse width 50ns). Leaving WDI unconnected or three-stated disables the watchdog.
5 VCC power_in Supply voltage input. Operating range 1V to 7V; L-version electrical characteristics apply at VCC=4.75V to 5.5V for the family, but this S-variant is monitored at a 2.93V reset threshold.

Key specifications

Parameter Value
Manufacturer Union Semiconductor
Package SOT-23-5
Category PMIC
Pins 5

Ordering variants

Same part, different packaging or reel option.

  • UM823SS
  • UM823SSSP

CAD (KiCad official)

  • Symbol: UM823SS
  • Footprint: Package_TO_SOT_SMD:SOT-23-5
  • 3D model: SOT-23-5 (KiCad packages3D, STEP)
  • 3D model files: um823ss-etched.step / um823ss-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); um823ss.step / um823ss.glb are the bare package body.

3D model downloads

Two STEP files. Same geometry, different body top:

File Size Use it when
um823ss.step 85 KB You want the bare part, or you mark your own boards.
um823ss-etched.step 1.9 MB You want the part with UM823SS already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 448 faces against 102 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

  • Datasheet: Union Semiconductor datasheet (11 pp, sha256 9413e8dcc1f62525, 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