UC3842BN
Public Unreviewedby Ray
STMicroelectronics AC-DC Controllers and Regulators, DIP-8. Datasheet-verified pinout, KiCad symbol/footprint/3D.
3D Model
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README
markdownUC3842BN
STMicroelectronics · AC-DC Controllers and Regulators · DIP-8
UC3842BN from STMicroelectronics, in a DIP-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 external loop compensation. Typically tied back to VFB (pin 2) through a compensation RC network to shape the closed-loop response. |
| 2 | VFB | input | Inverting input of the internal error amplifier. Normally connected to the switching power supply output through a resistor divider; the non-inverting input is internally tied to the 2.5 V reference. |
| 3 | ISENSE | input | Current-sense input. A voltage proportional to inductor / primary switch current (typically from a sense resistor) is applied here; the PWM latch terminates the output switch conduction when this voltage reaches ~1 V (max input signal 1.1 V). |
| 4 | RT/CT | passive | Oscillator timing pin. Oscillator frequency and maximum duty cycle are programmed by connecting timing resistor RT from VREF (pin 8) to this pin and timing capacitor CT from this pin to GROUND. Operation up to 500 kHz is possible. |
| 5 | GROUND | power_in | Combined control-circuitry and power ground return. All voltages in the datasheet are referenced to this pin; the high-current output return also flows through this pin, so single-point grounding of timing and bypass capacitors is required. |
| 6 | OUTPUT | output | High-current totem-pole gate-drive output for an external N-channel power MOSFET. Peak source/sink currents up to ±1 A; VOH typ 13.5 V, VOL typ 0.1 V at 20 mA; rise/fall times ~50 ns into 1 nF load. |
| 7 | VCC | power_in | Positive supply of the control IC (labeled Vi/VCC). UVLO turn-on threshold ~16 V, turn-off ~10 V (UC3842B/4B). Absolute maximum supply voltage 30 V (self-limiting via internal 36 V typ. zener at 25 mA). Startup current <0.5 mA, operating current ~12 mA typ. |
| 8 | VREF | power_out | Buffered 5 V ±2% reference output (5.00 V typ, 50 mA capable). Provides charging current for timing capacitor CT through resistor RT, and can be used to bias external circuitry. Short-circuit current internally limited (~-100 mA typ). |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | DIP-8 |
| Category | PMIC |
| Pins | 8 |
Ordering variants
Same part, different packaging or reel option.
UC3842BNNUC3842BND1
CAD (KiCad official)
- Symbol:
UC3842BN - Footprint:
Package_DIP:DIP-8_W7.62mm - 3D model: DIP-8 (KiCad packages3D, STEP)
3D model downloads
Two STEP files. Same geometry, different body top:
| File | Size | Use it when |
|---|---|---|
uc3842bn.step |
271 KB | You want the bare part, or you mark your own boards. |
uc3842bn-etched.step |
2.1 MB | You want the part with UC3842BN already on it. |
The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 500 faces against 148 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: STMicroelectronics datasheet (15 pp, sha256
62066370bcc6f048, 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).