component
LH001-91Q40AR2
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Legendsemi Analog Front End (AFE), QFN-40-EP(5x5). Datasheet-verified pinout, 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
markdownLH001-91Q40AR2
Legendsemi · Analog Front End (AFE) · QFN-40-EP(5x5)
LH001-91Q40AR2 from Legendsemi, in a QFN-40-EP(5x5). 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 | AIN0 | input | ADC analog input channel 0; input voltage range ±VREF/Gain. |
| 2 | AIN1 | input | ADC analog input channel 1; input voltage range ±VREF/Gain. |
| 3 | AIN2 | input | ADC analog input channel 2; input voltage range ±VREF/Gain. |
| 4 | AIN3 | input | ADC analog input channel 3; input voltage range ±VREF/Gain. |
| 5 | AIN4 | input | ADC analog input channel 4; input voltage range ±VREF/Gain. |
| 6 | AIN5 | input | ADC analog input channel 5; input voltage range ±VREF/Gain. |
| 7 | AVDD_REG | power_out | Analog 1.8V LDO output; connect 1μF capacitor to AVSS. |
| 8 | AVDD | power_in | Analog power supply; supply range 2.4V to 3.6V. |
| 9 | AIN6 | input | ADC analog input channel 6; input voltage range ±VREF/Gain. |
| 10 | AIN7 | input | ADC analog input channel 7; input voltage range ±VREF/Gain. |
| 11 | NC | unconnected | Not connected; leave unconnected. |
| 12 | NC | unconnected | Not connected; leave unconnected. |
| 13 | NC | unconnected | Not connected; leave unconnected. |
| 14 | NC | unconnected | Not connected; leave unconnected. |
| 15 | NC | unconnected | Not connected; leave unconnected. |
| 16 | NC | unconnected | Not connected; leave unconnected. |
| 17 | AVSS | power_in | Analog ground; connect to system ground. |
| 18 | DGND | power_in | Digital ground; connect to system ground. |
| 19 | DAISY_IN | input | SPI daisy-chain input; has internal weak pull-up, leave floating if unused. |
| 20 | VPP | power_in | OTP programming power supply; ground in user mode. |
| 21 | PDEXTRST | input | Power-down or system reset input, active low; has internal weak pull-up. |
| 22 | CLKSEL | input | Master clock selection input; selects clock source; has internal weak pull-up. |
| 23 | INTB | output | Digital interrupt output signal, active low; has internal weak pull-up. |
| 24 | CLK | bidirectional | External master clock input or internal oscillator output; selectable via configuration. |
| 25 | CSB | input | SPI chip select input, active low; must be low for SPI communication. |
| 26 | DIN | input | SPI serial data input; data latched on SCLK falling edge. |
| 27 | SCLK | input | SPI serial clock input; controls data transfer timing on DIN and DOUT. |
| 28 | DOUT | output | SPI serial data output; valid when CSB is low, high-impedance when CSB is high. |
| 29 | DRDYB | output | Data ready output, active low; signals completion of ADC conversion; has weak internal pull-up. |
| 30 | START | input | ADC conversion control input; rising edge starts conversion or use SPI START command. |
| 31 | GPIO0 | bidirectional | General-purpose digital input/output pin 0; configurable direction and pull resistors. |
| 32 | GPIO1 | bidirectional | General-purpose digital input/output pin 1; configurable direction and pull resistors. |
| 33 | DVDD_REG | power_out | Digital 1.8V LDO output; connect 1μF capacitor to DGND. |
| 34 | DVDD | power_in | Digital power supply; supply range 1.7V to 3.6V. |
| 35 | VREFN | input | ADC analog reference ground; must connect to AVSS for proper operation. |
| 36 | VREFP | bidirectional | ADC analog reference voltage input; connect 10μF capacitor to VREFN. |
| 37 | VREF | power_in | Internal reference voltage output (2V or 2.5V); connect 1μF capacitor to AVSS. |
| 38 | RLDOUT | output | Right leg drive amplifier output; drives common-mode return for ECG/EEG noise reduction. |
| 39 | RLDINV | input | Right leg drive amplifier inverting input; ground if RLD function not used. |
| 40 | RLDIN | input | Right leg drive input to multiplexer or RLD amplifier non-inverting input; connect to AVDD if unused. |
| 41 | EP | passive | Exposed pad (from the footprint; not named in the datasheet pin table). |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Legendsemi |
| Package | QFN-40-EP(5x5) |
| Category | Data Acquisition |
| Pins | 41 |
CAD (KiCad official)
- Symbol:
LH001-91Q40AR2 - Footprint:
Package_DFN_QFN:QFN-40-1EP_5x5mm_P0.4mm_EP3.6x3.6mm - 3D model: QFN-40-EP(5x5) (KiCad packages3D, STEP)
- 3D model files:
lh001-91q40ar2-etched.step/lh001-91q40ar2-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);lh001-91q40ar2.step/lh001-91q40ar2.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Legendsemi datasheet (46 pp, sha256
19fd2c03643b81d2, retrieved 2026-09-17, tier: lcsc) - Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- Extractor: parts-factory
2.0.0/extract_pins 0.2, primaryclaude-haiku-4-5-20251001(text), consensusclaude-sonnet-4-6(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).