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Contents

README

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UC3845BD1013TR

STMicroelectronics · AC-DC Controllers and Regulators · SO-8

UC3845BD1013TR from STMicroelectronics, in a SO-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 COMP output Error Amplifier output made available for loop compensation. A compensation network (Zf) is connected between COMP and VFB to shape the control loop response.
2 VFB input Inverting input of the internal Error Amplifier (non-inverting is tied to the internal 2.5 V reference). Normally connected to the switching power supply output through a resistor divider for output voltage regulation.
3 ISENSE input Current sense input. A voltage proportional to inductor/switch current (typically from a sense resistor Rs) is applied here; the PWM latch uses this to terminate output switch conduction on a cycle-by-cycle basis (peak Is ≈ 1.0 V / Rs, maximum input 1 V).
4 RT/CT passive Oscillator timing pin. Connect resistor RT from VREF (pin 8) and capacitor CT from this pin to GROUND to program frequency and maximum duty cycle. Operation up to 500 kHz is possible.
5 GROUND power_in Combined control-circuitry and power-stage ground return. All voltages are referenced to this pin; use single-point grounding at pin 5 for the timing/bypass capacitors due to high peak output currents.
6 OUTPUT output High-current totem-pole gate driver output for driving the gate of an external N-channel power MOSFET. Sources and sinks peak currents up to ±1 A; output is held low during UVLO.
7 VCC power_in Positive supply of the control IC (labeled Vi in the block diagram). For UC3845B, start-up threshold is 8.5 V (typ) and min operating (after turn-on) is 7.6 V; absolute max 30 V, self-limiting via internal 36 V zener. Start-up current <0.5 mA; operating supply current ≈12 mA.
8 VREF power_out Trimmed 5.00 V (±2%) reference output, up to 50 mA, used to source charging current for CT through RT and available for external circuitry. Short-circuit current is internally limited (~-100 mA typ).

Key specifications

Parameter Value
Manufacturer STMicroelectronics
Package SO-8
Category PMIC
Pins 8

Ordering variants

Same part, different packaging or reel option.

  • UC3845BD1013TR
  • UC3845BN

CAD (KiCad official)

  • Symbol: UC3845BD1013TR
  • Footprint: Package_SO:TI_SO-PowerPAD-8
  • 3D model: SO-8 (KiCad packages3D, STEP)

Provenance

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

  • Datasheet: STMicroelectronics datasheet (15 pp, sha256 fedfd7362400f8b3, 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