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UC3844G-SO8-R
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UTC Unisonic Tech AC-DC Controllers And Regulators, SOP-8. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownUC3844G-SO8-R
UTC Unisonic Tech · AC-DC Controllers And Regulators · SOP-8
UC3844G-SO8-R from UTC Unisonic Tech, in a SOP-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 | VFB | input | Inverting input of the error amplifier, normally connected to the switching power supply output through a resistor divider; the current sense and voltage feedback inputs are rated -0.3 V to +5.5 V. |
| 3 | ISENSE | input | Input proportional to inductor current that the PWM uses to terminate output switch conduction, with a maximum current sense input threshold of 0.9 V to 1.1 V (1.0 V typical). |
| 4 | RT/CT | passive | Oscillator timing pin: resistor RT connects to Vref and capacitor CT to ground to program the oscillator frequency and maximum output duty cycle, and operation to 1 MHz is possible. |
| 5 | GND | power_in | Power ground. |
| 6 | Output | output | Directly drives the gate of a power MOSFET, sourcing and sinking peak currents up to 1 A, and switches at one-half the oscillator frequency. |
| 7 | VCC | power_in | Positive supply; the total power supply and zener current (ICC+IZ) is rated at 30 mA maximum. |
| 8 | VREF | power_out | Reference output that provides charging current for capacitor CT through resistor RT, with a reference output voltage of 4.9 V to 5.1 V at IOUT = 1.0 mA and TJ = 25°C. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | UTC Unisonic Tech |
| Package | SOP-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 |
|---|---|---|---|---|---|---|---|
| Current Sense and Voltage feedback Inputs | VIN | -0.3 | 5.5 | V | 4 | ||
| Total Power Supply and Zener Current (ICC+IZ) | 30 | mA | 4 | ||||
| Error Amp Output Sink Current | ISINK | 10 | mA | 4 | |||
| Output Current, Source or Sink (Note 2) | IOUT | 1 | A | 4 | |||
| Output Energy (Capacitive Load per cycle) | W | 5 | μJ | 4 | |||
| Power Dissipation SOP-8 | PD | 800 | mW | 4 | |||
| Junction Temperature | TJ | 150 | °C | 4 | |||
| Operation Temperature | TOPR | 0 | 70 | °C | 4 | ||
| Storage Temperature | TSTG | -65 | 150 | °C | 4 | ||
| Junction to Ambient SOP-8 | θJA | 156 | °C/W | 4 | |||
| Reference Output Voltage | VREF | 4.9 | 5 | 5.1 | V | IOUT=1.0mA,TJ=25°C | 4 |
| Line Regulation | △VOUT | 2 | 20 | mV | VCC=12V ~ 25V | 4 | |
| Load Regulation | △VOUT | 3 | 25 | mV | IOUT=1.0mA ~ 20mA | 4 | |
| Total Output Variation over Line, Load, Temperature | VREF | 4.82 | 5.18 | V | 4 | ||
| Output Short Circuit Current | ISC | -30 | -85 | -180 | mA | 4 | |
| Frequency | fOSC | 47 | 52 | 57 | kHz | TJ=25°C | 4 |
| Frequency | fOSC | 46 | 60 | kHz | 0°C ≤ TA ≤ 70°C | 4 | |
| Frequency Change with Voltage | fOSC/V | 0.2 | 1 | % | VCC=12V ~ 25V | 4 | |
| Voltage Feedback Input | VFB | 2.42 | 2.5 | 2.58 | V | VOUT=2.5V | 4 |
| Output Voltage Swing High | VOH | 5 | 6.2 | V | RL=15k to ground, VFB=2.3V | 4 | |
| Output Voltage Swing Low | VOL | 0.8 | 1.1 | V | RL=15k to VREF, VFB=2.7V | 4 | |
| Output Current Sink | ISINK | 2 | 12 | mA | VOUT=1.1V, VFB=2.7V | 4 | |
| Output Current Source | ISOURCE | -0.5 | -1 | mA | VOUT=5.0V, VFB=2.3V | 4 | |
| Input Bias Current | II(BIAS) | -0.1 | -2 | μA | VFB=2.7V | 4 | |
| Open Loop Voltage Gain | GVO | 65 | 90 | dB | VOUT=2.0V ~ 4.0V | 4 | |
| Power Supply Rejection Ratio (error amp) | PSRR | 60 | 70 | dB | VCC=12V ~ 25V | 4 | |
| Unity Gain Bandwidth | GBW | 0.7 | 1 | MHz | TJ=25°C | 4 | |
| Current Sense Input Voltage Gain | GV | 2.85 | 3 | 3.15 | V/V | 5 | |
| Maximum Current Sense Input Threshold | VI(THR) | 0.9 | 1 | 1.1 | V | 5 | |
| Current Sense Input Bias Current | II(BIAS) | -2 | -10 | μA | 5 | ||
| Propagation Delay | tPLH(IN/OUT) | 150 | 300 | ns | 5 | ||
| Output Voltage Low | VOL | 0.1 | 0.4 | V | ISINK=20mA | 5 | |
| Output Voltage Low | VOL | 1.6 | 2.2 | V | ISINK=200mA | 5 | |
| Output Voltage High | VOH | 13 | 13.5 | V | ISINK=20mA | 5 | |
| Output Voltage High | VOH | 12 | 13.4 | V | ISINK=200mA | 5 | |
| Output Voltage with UVLO Activated | VOL(UVLO) | 0.1 | 1.1 | V | VCC=6.0V, ISINK=1.0mA | 5 | |
| Output Voltage Rise Time | tR | 50 | 150 | ns | CL=1.0nF,TJ=25°C | 5 | |
| Output Voltage Fall Time | tF | 50 | 150 | ns | CL=1.0nF,TJ=25°C | 5 | |
| Startup Threshold UC3844 | VTHR | 14.5 | 16 | 17.5 | V | 5 | |
| Minimum Operating Voltage After Turn-On UC3844 | VCC(MIN) | 8.5 | 10 | 11.5 | V | 5 | |
| Duty Cycle MAX | DCMAX | 47 | 48 | 50 | % | 5 | |
| Power Supply Zener Voltage | VZ | 30 | 36 | V | ICC=25mA | 5 | |
| Power Supply Current UC3844 | ICC | 12 | 17 | mA | VCC=14V | 5 | |
| Startup Current | ISTART-UP | 0.3 | 0.5 | mA | VCC=14V, UVLO Active | 5 |
CAD (KiCad official)
- Symbol:
UC3844G-SO8-R - Footprint:
Package_SO:SOIC-8_3.9x4.9mm_P1.27mm - 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files:
uc3844g-so8-r-etched.step/uc3844g-so8-r-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);uc3844g-so8-r.step/uc3844g-so8-r.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: UTC Unisonic Tech datasheet (7 pp, sha256
43d85764f509307f, retrieved 2026-10-18, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-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).