component
UC3845BD
Public Made by Adomby adom
lingxingic AC-DC Controllers And Regulators, SOP-8. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
main
UC3845BD
lingxingic · AC-DC Controllers And Regulators · SOP-8
UC3845BD from lingxingic, 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 | COMP | output | This is the error amplifier output, made available for loop compensation; the datasheet states the error amplifier output sink current is limited to 10 mA absolute maximum. |
| 2 | VFB | input | This is the inverting input of the error amplifier, normally connected to the switching power supply output through a resistor divider; the analog inputs are rated -0.3 V to +6.3 V. |
| 3 | ISENSE | input | A voltage proportional to inductor current is applied here and the PWM uses it to terminate output switch conduction; the current-sense maximum input signal is 1 V typical (0.9 V to 1.1 V). |
| 4 | RT/CT | passive | Resistor RT to VREF and capacitor CT to ground set the oscillator frequency and maximum output duty cycle, with operation to 500 kHz possible. |
| 5 | GROUND | power_in | This is the combined control circuitry and power ground. |
| 6 | OUTPUT | output | This output directly drives the gate of a power MOSFET, sourcing and sinking peak currents up to 1 A; the absolute maximum output current is ±1 A. |
| 7 | Vi | power_in | This is the positive supply of the control IC; the absolute maximum supply voltage is 30 V from a low impedance source. |
| 8 | VREF | power_out | This is the reference output, specified at 5.00 V typical (4.90 V to 5.10 V at Io = 1 mA), and it provides charging current for CT through RT. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | lingxingic |
| 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 |
|---|---|---|---|---|---|---|---|
| supply voltage (low impedance source) | Vi | 30 | V | low impedance source | 4 | ||
| output current | IO | -1 | 1 | A | 4 | ||
| power dissipation | PD | 1 | W | 4 | |||
| error amplifier output sink current | Isink(EA) | 10 | mA | 4 | |||
| analog inputs | Vin(EA) | -0.3 | 6.3 | V | 4 | ||
| operating temperature | Tamb | -40 | 85 | ℃ | 4 | ||
| storage temperature | Tstg | -65 | 150 | ℃ | 4 | ||
| soldering temperature (SOP8) | TL | 250 | ℃ | 10s, SOP8 | 4 | ||
| reference output voltage | VREF | 4.9 | 5 | 5.1 | V | Io=1mA | 4 |
| line regulation | ΔVREF | 2 | 20 | mV | 12V≤Vi≤25V | 4 | |
| load regulation | ΔVREF | 3 | 25 | mV | 1≤Io≤20mA | 4 | |
| total output variation | VREF | 4.82 | 5.18 | V | line, load, temperature | 4 | |
| output short circuit current | ISC | -30 | -100 | -180 | mA | 4 | |
| oscillator frequency | fOSC | 49 | 52 | 55 | kHz | Tj=25℃ | 4 |
| oscillator frequency over temperature range | fOSC | 48 | 56 | kHz | Tamb=Tlow to Thigh, Tj=25℃ | 4 | |
| oscillator frequency (RT/CT test point) | fOSC | 225 | 250 | 275 | kHz | Tj=25℃, RT=6.2kΩ, CT=1nF | 4 |
| frequency change with voltage | ΔfOSC/ΔV | 0.2 | 1 | % | Vi=12V~25V | 4 | |
| discharge current | Idischg | 7.8 | 8.3 | 8.8 | mA | VOSC=2V, Tj=25℃, Tamb=-40 to 85℃ | 4 |
| error amplifier input voltage | V2 | 2.42 | 2.5 | 2.58 | V | VPIN1=2.5V | 4 |
| input bias current | Ib | -0.1 | -2 | uA | VFB=5V | 4 | |
| error amplifier open-loop gain | AVOL | 65 | 90 | dB | 2V≤Vo≤4V | 4 | |
| unity gain bandwidth | BW | 0.7 | 1 | MHz | Tj=25℃ | 4 | |
| power supply rejection ratio | PSRR | 60 | 70 | dB | 12V≤Vi≤25V | 5 | |
| error amplifier output sink current | IO | 2 | 12 | mA | VPIN2=2.7V, VPIN1=1.1V | 5 | |
| error amplifier output source current | IO | -0.5 | -1 | mA | VPIN2=2.3V, VPIN1=5V | 5 | |
| VOUT high | VOUT High | 5 | 6.2 | V | VPIN2=2.3V; RL=15KΩ to ground | 5 | |
| VOUT low | VOUT Low | 0.8 | 1.1 | V | VPIN2=2.7V; RL=15KΩ to PIN 8 | 5 | |
| current sense gain | GV | 2.85 | 3 | 3.15 | V/V | 5 | |
| maximum input signal | V3 | 0.9 | 1 | 1.1 | V | VPIN1=5V | 5 |
| current sense supply voltage rejection | SVR | 70 | dB | 12V≤Vi≤25V | 5 | ||
| current sense input bias current | Ib | -2 | -10 | uA | 5 | ||
| delay to output | 150 | 300 | ns | 5 | |||
| output low level (20mA) | VOL | 0.1 | 0.4 | V | Isink=20mA | 5 | |
| output low level (200mA) | VOL | 1.6 | 2.2 | V | Isink=200mA | 5 | |
| output high level (20mA) | VOH | 13 | 13.5 | V | Isource=20mA | 5 | |
| output high level (200mA) | VOH | 12 | 13.5 | V | Isource=200mA | 5 | |
| UVLO saturation | VOLS | 0.1 | 1.1 | V | Vi=6V, ISINK=1mA | 5 | |
| output rise time | tr | 50 | 150 | ns | CL=1nF | 5 | |
| output fall time | tf | 50 | 150 | ns | CL=1nF | 5 | |
| UVLO start threshold (UC3843/5) | VTH(ST) | 7.8 | 8.8 | 9.4 | V | UC3843/5 | 5 |
| UVLO minimum operating voltage after turn-on (UC3843/5) | VOPR(MIN) | 7 | 7.6 | 8.2 | V | UC3843/5 | 5 |
| maximum duty cycle (UC3844/5) | 47 | 48 | 50 | % | UC3844/5 | 5 | |
| minimum duty cycle | 0 | % | 5 | ||||
| start-up current (UC3843/5) | Ist | 0.3 | 0.5 | mA | Vi=6.5V, UC3843/5 | 5 | |
| operating supply current | Ii | 12 | 20 | mA | VPIN2=VPIN3=0V | 5 | |
| zener voltage | Viz | 30 | 36 | V | Ii=25mA | 5 |
CAD (KiCad official)
- Symbol:
UC3845BD - Footprint:
Package_SO:SOIC-8_3.9x4.9mm_P1.27mm - 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files:
uc3845bd-etched.step/uc3845bd-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);uc3845bd.step/uc3845bd.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: lingxingic datasheet (9 pp, sha256
796cb0db85826697, 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).
# UC3845BD
**lingxingic** · AC-DC Controllers And Regulators · SOP-8
UC3845BD from lingxingic, 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 | COMP | output | This is the error amplifier output, made available for loop compensation; the datasheet states the error amplifier output sink current is limited to 10 mA absolute maximum. |
| 2 | VFB | input | This is the inverting input of the error amplifier, normally connected to the switching power supply output through a resistor divider; the analog inputs are rated -0.3 V to +6.3 V. |
| 3 | ISENSE | input | A voltage proportional to inductor current is applied here and the PWM uses it to terminate output switch conduction; the current-sense maximum input signal is 1 V typical (0.9 V to 1.1 V). |
| 4 | RT/CT | passive | Resistor RT to VREF and capacitor CT to ground set the oscillator frequency and maximum output duty cycle, with operation to 500 kHz possible. |
| 5 | GROUND | power_in | This is the combined control circuitry and power ground. |
| 6 | OUTPUT | output | This output directly drives the gate of a power MOSFET, sourcing and sinking peak currents up to 1 A; the absolute maximum output current is ±1 A. |
| 7 | Vi | power_in | This is the positive supply of the control IC; the absolute maximum supply voltage is 30 V from a low impedance source. |
| 8 | VREF | power_out | This is the reference output, specified at 5.00 V typical (4.90 V to 5.10 V at Io = 1 mA), and it provides charging current for CT through RT. |
## Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | lingxingic |
| 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 |
|---|---|---|---|---|---|---|---|
| supply voltage (low impedance source) | Vi | | | 30 | V | low impedance source | 4 |
| output current | IO | -1 | | 1 | A | | 4 |
| power dissipation | PD | | | 1 | W | | 4 |
| error amplifier output sink current | Isink(EA) | | | 10 | mA | | 4 |
| analog inputs | Vin(EA) | -0.3 | | 6.3 | V | | 4 |
| operating temperature | Tamb | -40 | | 85 | ℃ | | 4 |
| storage temperature | Tstg | -65 | | 150 | ℃ | | 4 |
| soldering temperature (SOP8) | TL | | | 250 | ℃ | 10s, SOP8 | 4 |
| reference output voltage | VREF | 4.9 | 5 | 5.1 | V | Io=1mA | 4 |
| line regulation | ΔVREF | | 2 | 20 | mV | 12V≤Vi≤25V | 4 |
| load regulation | ΔVREF | | 3 | 25 | mV | 1≤Io≤20mA | 4 |
| total output variation | VREF | 4.82 | | 5.18 | V | line, load, temperature | 4 |
| output short circuit current | ISC | -30 | -100 | -180 | mA | | 4 |
| oscillator frequency | fOSC | 49 | 52 | 55 | kHz | Tj=25℃ | 4 |
| oscillator frequency over temperature range | fOSC | 48 | | 56 | kHz | Tamb=Tlow to Thigh, Tj=25℃ | 4 |
| oscillator frequency (RT/CT test point) | fOSC | 225 | 250 | 275 | kHz | Tj=25℃, RT=6.2kΩ, CT=1nF | 4 |
| frequency change with voltage | ΔfOSC/ΔV | | 0.2 | 1 | % | Vi=12V~25V | 4 |
| discharge current | Idischg | 7.8 | 8.3 | 8.8 | mA | VOSC=2V, Tj=25℃, Tamb=-40 to 85℃ | 4 |
| error amplifier input voltage | V2 | 2.42 | 2.5 | 2.58 | V | VPIN1=2.5V | 4 |
| input bias current | Ib | | -0.1 | -2 | uA | VFB=5V | 4 |
| error amplifier open-loop gain | AVOL | 65 | 90 | | dB | 2V≤Vo≤4V | 4 |
| unity gain bandwidth | BW | 0.7 | 1 | | MHz | Tj=25℃ | 4 |
| power supply rejection ratio | PSRR | 60 | 70 | | dB | 12V≤Vi≤25V | 5 |
| error amplifier output sink current | IO | 2 | 12 | | mA | VPIN2=2.7V, VPIN1=1.1V | 5 |
| error amplifier output source current | IO | -0.5 | -1 | | mA | VPIN2=2.3V, VPIN1=5V | 5 |
| VOUT high | VOUT High | 5 | 6.2 | | V | VPIN2=2.3V; RL=15KΩ to ground | 5 |
| VOUT low | VOUT Low | | 0.8 | 1.1 | V | VPIN2=2.7V; RL=15KΩ to PIN 8 | 5 |
| current sense gain | GV | 2.85 | 3 | 3.15 | V/V | | 5 |
| maximum input signal | V3 | 0.9 | 1 | 1.1 | V | VPIN1=5V | 5 |
| current sense supply voltage rejection | SVR | | | 70 | dB | 12V≤Vi≤25V | 5 |
| current sense input bias current | Ib | | -2 | -10 | uA | | 5 |
| delay to output | | | 150 | 300 | ns | | 5 |
| output low level (20mA) | VOL | | 0.1 | 0.4 | V | Isink=20mA | 5 |
| output low level (200mA) | VOL | | 1.6 | 2.2 | V | Isink=200mA | 5 |
| output high level (20mA) | VOH | 13 | 13.5 | | V | Isource=20mA | 5 |
| output high level (200mA) | VOH | 12 | 13.5 | | V | Isource=200mA | 5 |
| UVLO saturation | VOLS | | 0.1 | 1.1 | V | Vi=6V, ISINK=1mA | 5 |
| output rise time | tr | | 50 | 150 | ns | CL=1nF | 5 |
| output fall time | tf | | 50 | 150 | ns | CL=1nF | 5 |
| UVLO start threshold (UC3843/5) | VTH(ST) | 7.8 | 8.8 | 9.4 | V | UC3843/5 | 5 |
| UVLO minimum operating voltage after turn-on (UC3843/5) | VOPR(MIN) | 7 | 7.6 | 8.2 | V | UC3843/5 | 5 |
| maximum duty cycle (UC3844/5) | | 47 | 48 | 50 | % | UC3844/5 | 5 |
| minimum duty cycle | | | | 0 | % | | 5 |
| start-up current (UC3843/5) | Ist | | 0.3 | 0.5 | mA | Vi=6.5V, UC3843/5 | 5 |
| operating supply current | Ii | | 12 | 20 | mA | VPIN2=VPIN3=0V | 5 |
| zener voltage | Viz | 30 | 36 | | V | Ii=25mA | 5 |
## CAD (KiCad official)
- Symbol: `UC3845BD`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `uc3845bd-etched.step` / `uc3845bd-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `uc3845bd.step` / `uc3845bd.glb` are the bare package body.
## Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- **Datasheet:** [lingxingic datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8603345531880431616) (9 pp, sha256 `796cb0db85826697`, retrieved 2026-10-18, 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](docs/uc3845bd-datasheet.pdf)