# AFE4400RHAR

**Texas Instruments** · Analog Front End (AFE) · VQFN-40(6x6)

AFE4400RHAR from Texas Instruments, in a VQFN-40(6x6). 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 | INN | input | Receiver analog input pin, connect to photodiode anode. |
| 2 | INP | input | Receiver analog input pin, connect to photodiode cathode. |
| 3 | RX_ANA_GND | power_in | Rx analog ground pin, connect to common board ground. |
| 4 | VCM | output | Input common-mode voltage output reference; connect 1 kΩ series resistor and 10 nF decoupling capacitor to ground for biasing and shielding. |
| 5 | DNC | unconnected | Do not connect; leave as open circuit. |
| 6 | DNC | unconnected | Do not connect; leave as open circuit. |
| 7 | BG | power_out | Internal bandgap reference voltage output; connect 2.2 µF decoupling capacitor to ground. |
| 8 | VSS | power_in | Substrate ground pin, connect to common board ground. |
| 9 | TX_REF | power_out | Transmitter reference voltage output (0.75 V default); connect 2.2 µF decoupling capacitor to ground. |
| 10 | DNC | unconnected | Do not connect; leave as open circuit. |
| 11 | TX_CTRL_SUP | power_in | Transmit controller supply pin (3.0 V to 5.25 V); connect 0.1 µF decoupling capacitor to ground. |
| 12 | LED_DRV_GND | power_in | LED driver ground pin for H-bridge, connect to common board ground. |
| 13 | LED_DRV_GND | power_in | LED driver ground pin for H-bridge, connect to common board ground. |
| 14 | TXN | output | LED driver analog output (H-bridge output B); connect to LED. |
| 15 | TXP | output | LED driver analog output (H-bridge output A); connect to LED. |
| 16 | LED_DRV_GND | power_in | LED driver ground pin for H-bridge, connect to common board ground. |
| 17 | LED_DRV_SUP | power_in | LED driver supply pin for H-bridge (3.0 V to 5.25 V), capable of supplying large LED current. |
| 18 | LED_DRV_SUP | power_in | LED driver supply pin for H-bridge (3.0 V to 5.25 V), capable of supplying large LED current. |
| 19 | RX_DIG_GND | power_in | Rx digital ground pin, connect to common board ground. |
| 20 | AFE_PDN | input | AFE power-down input (active low); can be connected to microcontroller port pin. |
| 21 | DIAG_END | output | Diagnostic completion status output signal; can be connected to microcontroller port pin. |
| 22 | LED_ALM | output | LED cable fault detection alarm output signal; can be connected to microcontroller port pin. |
| 23 | PD_ALM | output | Photodiode sensor or cable fault detection alarm output signal; can be connected to microcontroller port pin. |
| 24 | SCLK | input | SPI serial clock input pin with Schmitt-triggered input. |
| 25 | SPISOMI | output | SPI serial data output pin (Master In Slave Out / slave output). |
| 26 | SPISIMO | input | SPI serial data input pin (Master Out Slave In / slave input). |
| 27 | SPISTE | input | SPI serial interface enable (chip select) input pin. |
| 28 | ADC_RDY | output | ADC conversion completion indicator output signal; can be connected to microcontroller interrupt input. |
| 29 | RESET | input | AFE reset input (active low); can be connected to microcontroller port pin. |
| 30 | CLKOUT | output | Buffered 4 MHz output clock from internal crystal oscillator; can be connected to microcontroller clock input. |
| 31 | RX_DIG_SUP | power_in | Rx digital supply pin (2.0 V to 3.6 V); connect 0.1 µF decoupling capacitor to ground. |
| 32 | RX_DIG_GND | power_in | Rx digital ground pin, connect to common board ground. |
| 33 | RX_ANA_SUP | power_in | Rx analog supply pin (2.0 V to 3.6 V); connect 0.1 µF decoupling capacitor to ground. |
| 34 | DNC | unconnected | Do not connect; leave as open circuit. |
| 35 | DNC | unconnected | Do not connect; leave as open circuit. |
| 36 | RX_ANA_GND | power_in | Rx analog ground pin, connect to common board ground. |
| 37 | XOUT | output | Crystal oscillator output pin; connect external 8 MHz crystal with load capacitor to ground. |
| 38 | XIN | input | Crystal oscillator input pin; connect external 8 MHz crystal with load capacitor to ground. |
| 39 | RX_ANA_SUP | power_in | Rx analog supply pin (2.0 V to 3.6 V); connect 0.1 µF decoupling capacitor to ground. |
| 40 | RX_ANA_GND | power_in | Rx analog ground pin, connect to common board ground. |
| 41 | EP | passive | Exposed pad (from the footprint; not named in the datasheet pin table). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | VQFN-40(6x6) |
| Category | Data Acquisition |
| Pins | 41 |

## CAD (KiCad official)

- Symbol: `AFE4400RHAR`
- Footprint: `Package_DFN_QFN:QFN-40-1EP_6x6mm_P0.5mm_EP4.6x4.6mm`
- 3D model: VQFN-40(6x6) (KiCad packages3D, STEP)
- 3D model files: `afe4400rhar-etched.step` / `afe4400rhar-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `afe4400rhar.step` / `afe4400rhar.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/cn/lit/gpn/afe4400) (84 pp, sha256 `d0befbf8c7df9113`, retrieved 2026-09-18, 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`, primary `claude-haiku-4-5-20251001` (text), consensus `claude-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).

[Datasheet PDF](docs/afe4400rhar-datasheet.pdf)