component
lm4861mx
Public Unreviewedby Ray
Texas Instruments Audio Power OpAmps, SOIC-8. Datasheet-verified pinout, KiCad symbol/footprint/3D.
3D Model
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README
markdownLM4861MX
Texas Instruments · Audio Power OpAmps · SOIC-8
LM4861MX from Texas Instruments, in a SOIC-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 | SHUTDOWN | input | Active-high shutdown control. Drive to VDD to disable the amplifier (typical shutdown current 0.6µA); drive to GND to enable. Must not be left floating - no internal pull-down exists. An external 47kΩ pull-up can be used with a switch to GND to enable. |
| 2 | BYPASS | passive | Half-supply (VDD/2) internal reference bypass node. Connect an external bypass capacitor CB (typ 1.0µF) from this pin to GND to filter the half-supply reference; larger CB improves low-frequency THD+N. |
| 3 | +IN | input | Non-inverting input of the first (gain-configurable) amplifier. Typically tied to the BYPASS (VDD/2) node through a resistor in bridged applications so the amplifier's input is biased at half-supply. |
| 4 | -IN | input | Inverting input of the first amplifier. Closed-loop differential gain is set by Rf/Ri (Avd = 2·Rf/Ri); connect the audio input through a coupling capacitor Ci and series resistor Ri, with feedback resistor Rf from Vo1 to this pin. |
| 5 | Vo1 | output | Output of the first (gain-configurable) amplifier. One side of the bridge-tied load; biased at VDD/2. Drives the 8Ω load differentially with Vo2 (180° out of phase). Delivers up to 1.1W (1% THD+N) into 8Ω at VDD = 5V. |
| 6 | VDD | power_in | Positive supply voltage input, 2.0V to 5.5V operating range (6.0V absolute maximum). Typical quiescent current 6.5mA. Bypass locally with a 0.1µF ceramic capacitor as close as possible to the pin for low-noise operation and high PSRR. |
| 7 | GND | power_in | Ground reference return. All voltages are measured with respect to this pin. |
| 8 | Vo2 | output | Output of the second amplifier, internally fixed at unity gain in an inverting configuration (Av = -1) via two internal 40kΩ resistors. Forms the second half of the bridge-tied load with Vo1; biased at VDD/2 and 180° out of phase with Vo1. In single-ended use, load with a 0.1µF + 2kΩ dummy network for stability. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-8 |
| Category | Op-amp/Cmp |
| Pins | 8 |
Ordering variants
LM4861MXLM4861MXLM4861M/NOPBLM4861MX/NOPB
CAD (KiCad official)
- Symbol:
LM4861MX - Footprint:
Package_SO:SOIC-8_3.9x4.9mm_P1.27mm - 3D model: SOIC-8 (KiCad packages3D, STEP)
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Texas Instruments datasheet (None pp, sha256
d212743516cb9c3a, retrieved 2026-08-17, tier: manufacturer) - 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).
Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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