component

UC3845BNG

Public Made by Adom

by adom

onsemi AC-DC Controllers And Regulators, PDIP-8. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

componentpower management (pmic)uc3845bngfactory-2.0.0extractor-text
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Datasheet

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Contents

README

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UC3845BNG

onsemi · AC-DC Controllers And Regulators · PDIP-8

UC3845BNG from onsemi, in a PDIP-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 Compensation output Error Amplifier output, made available for loop compensation.
2 Voltage Feedback input Inverting input of the Error Amplifier, normally connected to the switching power supply output through a resistor divider.
3 Current Sense input Input for a voltage proportional to inductor current, which the PWM uses to terminate output switch conduction.
4 RT/CT passive Oscillator frequency and maximum output duty cycle are set by resistor RT to Vref and capacitor CT to ground; oscillator operation to 1.0 kHz is possible.
5 GND power_in Combined control circuitry and power ground.
6 Output output Directly drives the gate of a power MOSFET, sourcing and sinking peak currents up to 1.0 A and switching at one-half the oscillator frequency.
7 VCC power_in Positive supply of the control IC.
8 Vref power_out Reference output (5.0 V) that provides charging current for capacitor CT through resistor RT.

Key specifications

Parameter Value
Manufacturer onsemi
Package PDIP-8
Category Power Management (PMIC)
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
Total output variation over line, load and temperature (UC384xB) Vref 4.82 5.18 V 2
Reference output voltage Vref 4.9 5 5.1 V IO = 1.0 mA, TJ = 25°C 2
Startup threshold (UCX845B, BV) Vth 7.8 8.4 9 V UCX845B, BV 3
Minimum operating voltage after turn-on (UCX845B, BV) VCC(min) 7 7.6 8.2 V UCX845B, BV 3
Maximum duty cycle (UC384XB) DC(max) 47 48 50 % UC384XB 4
Minimum duty cycle DC(min) 0 % 4
Discharge current, TJ = 25°C Idischg 7.8 8.3 8.8 mA VOSC = 2.0 V, TJ = 25°C 3
Discharge current, TA = Tlow to Thigh (UC384XB) Idischg 7.6 8.8 mA VOSC = 2.0 V, TA = Tlow to Thigh 3
Error amplifier voltage feedback input VFB 2.42 2.5 2.58 V VO = 2.5 V 3
Open loop voltage gain AVOL 65 90 dB VO = 2.0 V to 4.0 V 3
Unity gain bandwidth BW 0.7 1 MHz TJ = 25°C 3
Error amplifier power supply rejection ratio PSRR 60 70 dB VCC = 12 V to 25 V 3
Current sense input voltage gain (UC384XB) AV 2.85 3 3.15 V/V 3
Maximum current sense input threshold (UC384XB) Vth 0.9 1 1.1 V Note 9 3
Current sense power supply rejection ratio PSRR 70 dB VCC = 12 V to 25 V (Note 9) 3
Propagation delay, current sense input to output tPLH(In/Out) 150 300 ns 3
Output voltage rise time tr 50 150 ns CL = 1.0 nF, TJ = 25°C 3
Output voltage fall time tf 50 150 ns CL = 1.0 nF, TJ = 25°C 3
Output voltage with UVLO activated VOL(UVLO) 0.1 1.1 V VCC = 6.0 V, ISink = 1.0 mA 3
Power supply current, startup ICC 0.3 0.5 mA VCC = 6.5 V for UCX845B 4
Power supply current, operating ICC 12 17 mA Note 11 4
Power supply zener voltage VZ 30 36 V ICC = 25 mA 4
Output short circuit current ISC -30 -85 -180 mA 2
Line regulation Regline 2 20 mV VCC = 12 V to 25 V 2
Load regulation Regload 3 25 mV IO = 1.0 mA to 20 mA 2
Temperature stability TS 0.2 mV/°C 2
Output noise voltage Vn 50 V f = 10 Hz to 10 kHz, TJ = 25°C 2
Long term stability S 5 mV TA = 125°C for 1000 Hours 2
Frequency change with voltage fOSC/V 0.2 1 % VCC = 12 V to 25 V 2
Frequency change with temperature fOSC/T 0.5 % TA = Tlow to Thigh 2
Oscillator voltage swing (peak-to-peak) VOSC 1.6 V 2
Absolute max: bias and driver voltages VCC, VC VCC, VC 36 V Zero series impedance (Note 1) 2
Absolute max: total power supply and zener current ICC + IZ 30 mA 2
Absolute max: output current, source or sink IO 1 A Note 2 2
Absolute max: output energy (capacitive load per cycle) W 5 J Capacitive load per cycle 2
Absolute max: current sense and voltage feedback inputs Vin -0.3 5.5 V 2
Absolute max: error amp output sink current IO 10 mA 2
Absolute max: operating junction temperature TJ 150 °C 2
Absolute max: storage temperature range Tstg -65 150 °C 2
Operating ambient temperature (UC3844B, UC3845B) TA 0 70 °C UC3844B, UC3845B 2
Maximum power dissipation, PDIP-8 N suffix PD 1.25 W TA = 25°C 2
Thermal resistance, junction-to-air, PDIP-8 N suffix RJA 100 °C/W Junction-to-air 2

CAD (KiCad official)

  • Symbol: UC3845BNG
  • Footprint: Package_DIP:DIP-8_W7.62mm
  • 3D model: PDIP-8 (KiCad packages3D, STEP)
  • 3D model files: uc3845bng-etched.step / uc3845bng-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); uc3845bng.step / uc3845bng.glb are the bare package body.

Provenance

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

  • Datasheet: onsemi datasheet (19 pp, sha256 e69ff39fc0ea9e08, retrieved 2026-10-15, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus claude-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).

Datasheet PDF