component
UC3845BD1R2G
Public Made by Adomby adom
onsemi AC-DC Controllers and Regulators, SOIC-8. Pinout extracted from the datasheet, KiCad symbol/footprint/3D.
main
Ray
pin 1: carry the footprint's marker into the .lbr, the viewer and page.json (silk-marker, drawn, top-left)
eb63216
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{
"schema": "adom.pads/1",
"slug": "uc3845bd1r2g",
"footprint": "SOIC-8_3.9x4.9mm_P1.27mm",
"generated_from": {
"footprint": "SOIC-8_3.9x4.9mm_P1.27mm@sha256:074ecb2092b24fa4",
"pins": "page.json:component.pins",
"overrides": null
},
"pin1": {
"pad": "1",
"at": [
-2.475,
-1.905
],
"corner": "top-left",
"source": "silk-marker",
"derived_from": "SOIC-8_3.9x4.9mm_P1.27mm@sha256:074ecb2092b24fa4"
},
"pad_count": 8,
"symbol_pins": [
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8"
],
"paste_apertures": 0,
"issues": [],
"pads": [
{
"pad": "1",
"kind": "smd",
"shape": "roundrect",
"at": [
-2.475,
-1.905
],
"rot": 0.0,
"size": [
1.95,
0.6
],
"layers": [
"F.Cu",
"F.Mask",
"F.Paste"
],
"thermal": false,
"pin": "1",
"name": "Compensation",
"type": "output",
"description": "Error amplifier output / compensation node. External RC network to Voltage Feedback (pin 2) sets the closed-loop gain and frequency response of the error amplifier used for output regulation.",
"is_pin1": true,
"source": {
"geometry": "SOIC-8_3.9x4.9mm_P1.27mm.kicad_mod",
"meaning": "page.json:component.pins",
"correspondence": "kicad: symbol pin number == pad name"
}
},
{
"pad": "2",
"kind": "smd",
"shape": "roundrect",
"at": [
-2.475,
-0.635
],
"rot": 0.0,
"size": [
1.95,
0.6
],
"layers": [
"F.Cu",
"F.Mask",
"F.Paste"
],
"thermal": false,
"pin": "2",
"name": "Voltage Feedback",
"type": "input",
"description": "Inverting input of the on-chip 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 (VFB regulation set point ~2.5 V).",
"is_pin1": false,
"source": {
"geometry": "SOIC-8_3.9x4.9mm_P1.27mm.kicad_mod",
"meaning": "page.json:component.pins",
"correspondence": "kicad: symbol pin number == pad name"
}
},
{
"pad": "3",
"kind": "smd",
"shape": "roundrect",
"at": [
-2.475,
0.635
],
"rot": 0.0,
"size": [
1.95,
0.6
],
"layers": [
"F.Cu",
"F.Mask",
"F.Paste"
],
"thermal": false,
"pin": "3",
"name": "Current Sense",
"type": "input",
"description": "Non-inverting input of the current-sense comparator. Monitors the MOSFET source current across a sense resistor; the internal PWM latch is reset (output terminates) when this pin reaches the threshold set by the error amp output (nominal max threshold 1.0 V).",
"is_pin1": false,
"source": {
"geometry": "SOIC-8_3.9x4.9mm_P1.27mm.kicad_mod",
"meaning": "page.json:component.pins",
"correspondence": "kicad: symbol pin number == pad name"
}
},
{
"pad": "4",
"kind": "smd",
"shape": "roundrect",
"at": [
-2.475,
1.905
],
"rot": 0.0,
"size": [
1.95,
0.6
],
"layers": [
"F.Cu",
"F.Mask",
"F.Paste"
],
"thermal": false,
"pin": "4",
"name": "RT/CT",
"type": "passive",
"description": "Oscillator timing pin. External resistor RT to Vref and timing capacitor CT to GND set the oscillator frequency (fOSC ≈ 1.72 / (RT·CT) for RT > 5 kΩ). Output switching frequency equals oscillator frequency.",
"is_pin1": false,
"source": {
"geometry": "SOIC-8_3.9x4.9mm_P1.27mm.kicad_mod",
"meaning": "page.json:component.pins",
"correspondence": "kicad: symbol pin number == pad name"
}
},
{
"pad": "5",
"kind": "smd",
"shape": "roundrect",
"at": [
2.475,
1.905
],
"rot": 0.0,
"size": [
1.95,
0.6
],
"layers": [
"F.Cu",
"F.Mask",
"F.Paste"
],
"thermal": false,
"pin": "5",
"name": "GND",
"type": "power_in",
"description": "Device ground and current return for control circuitry and totem-pole output stage. In the SOIC-8/PDIP-8 package the signal and power grounds share this pin (the SOIC-14 D-suffix splits them).",
"is_pin1": false,
"source": {
"geometry": "SOIC-8_3.9x4.9mm_P1.27mm.kicad_mod",
"meaning": "page.json:component.pins",
"correspondence": "kicad: symbol pin number == pad name"
}
},
{
"pad": "6",
"kind": "smd",
"shape": "roundrect",
"at": [
2.475,
0.635
],
"rot": 0.0,
"size": [
1.95,
0.6
],
"layers": [
"F.Cu",
"F.Mask",
"F.Paste"
],
"thermal": false,
"pin": "6",
"name": "Output",
"type": "output",
"description": "High-current totem-pole gate-drive output for the external power MOSFET. Capable of ±1 A peak source/sink; typical VOH ≈ 13.5 V and VOL ≈ 0.1 V at 20 mA. Rise/fall times ~50 ns into 1 nF.",
"is_pin1": false,
"source": {
"geometry": "SOIC-8_3.9x4.9mm_P1.27mm.kicad_mod",
"meaning": "page.json:component.pins",
"correspondence": "kicad: symbol pin number == pad name"
}
},
{
"pad": "7",
"kind": "smd",
"shape": "roundrect",
"at": [
2.475,
-0.635
],
"rot": 0.0,
"size": [
1.95,
0.6
],
"layers": [
"F.Cu",
"F.Mask",
"F.Paste"
],
"thermal": false,
"pin": "7",
"name": "VCC",
"type": "power_in",
"description": "Positive supply for the control IC and output driver. UVLO thresholds for the UC3845B are 8.5 V (on) / 7.6 V (off). Absolute max 36 V (internally zener-clamped); typical startup current 0.3 mA, operating current ~12 mA.",
"is_pin1": false,
"source": {
"geometry": "SOIC-8_3.9x4.9mm_P1.27mm.kicad_mod",
"meaning": "page.json:component.pins",
"correspondence": "kicad: symbol pin number == pad name"
}
},
{
"pad": "8",
"kind": "smd",
"shape": "roundrect",
"at": [
2.475,
-1.905
],
"rot": 0.0,
"size": [
1.95,
0.6
],
"layers": [
"F.Cu",
"F.Mask",
"F.Paste"
],
"thermal": false,
"pin": "8",
"name": "Vref",
"type": "power_out",
"description": "Buffered 5.0 V ±1% precision reference output (4.95-5.05 V at 25 °C, 1 mA). Sources up to ~50 mA to bias external circuitry and to feed the oscillator timing resistor RT. Short-circuit protected (~85 mA typ).",
"is_pin1": false,
"source": {
"geometry": "SOIC-8_3.9x4.9mm_P1.27mm.kicad_mod",
"meaning": "page.json:component.pins",
"correspondence": "kicad: symbol pin number == pad name"
}
}
]
}