# MAX3485

**Analog Devices** · RS-485 Transceiver · SOIC-8

The MAX3485 is a 3.3 V half-duplex RS-485/RS-422 transceiver with a driver and receiver in one package, each with an enable. It converts logic-level UART signals to the differential A/B bus and back for reliable multidrop communication over long cables (Modbus, industrial networks), at data rates up to 10 Mbps.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | RO | output | Receiver Output. If A > B by 200mV, RO will be high; if A < B by 200mV, RO will be low. Drives to VOH = VCC - 0.4V (min) at IOUT = -1.5mA. |
| 2 | RE | input | Receiver Output Enable (active-low). RO is enabled when RE is low; RO is high-impedance when RE is high. VIH = 2.0V min, VIL = 0.8V max. |
| 3 | DE | input | Driver Output Enable. Driver outputs A and B are enabled when DE is high and high-impedance when DE is low. VIH = 2.0V min, VIL = 0.8V max. |
| 4 | DI | input | Driver Input. A low on DI forces output A low and output B high; a high on DI forces output A high and output B low. VIH = 2.0V min, VIL = 0.8V max. |
| 5 | GND | power_in | Ground reference. |
| 6 | A | bidirectional | Noninverting Receiver Input and Noninverting Driver Output (half-duplex). Differential bus pin; -7V to +12V common-mode range; VOD (differential driver output) = 1.5V min with RL = 54Ω. |
| 7 | B | bidirectional | Inverting Receiver Input and Inverting Driver Output (half-duplex). Differential bus pin; -7V to +12V common-mode range; complementary to A. |
| 8 | VCC | power_in | Positive Supply: 3.0V ≤ VCC ≤ 3.6V. ICC ≈ 1.1mA typ (2.2mA max) with no load. |

## Key specifications

| Parameter | Value |
|---|---|
| Type | Half-duplex RS-485/RS-422 transceiver |
| Supply voltage | 3.0 V to 3.6 V |
| Data rate | Up to 10 Mbps |
| Bus | Differential A / B, up to 32 nodes |
| Enables | Separate driver (DE) and receiver (RE) |
| Operating temperature | -40 C to 85 C |

## Ordering variants

Same part, different packaging or reel option.

- `MAX3485CSA`
- `MAX3485ESA`
- `MAX3485CPA`
- `MAX3485EPA`
- `MAX3485C/D`

## CAD (KiCad official)

- Symbol: `max3485.kicad_sym`
- Footprint: `max3485.kicad_mod`
- 3D model: SOIC-8 body from KiCad `Package_SO/SOIC-8_3.9x4.9mm_P1.27mm`.
- 3D model files: `max3485-etched.step` / `max3485-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `max3485.step` / `max3485.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Analog Devices datasheet](https://www.analog.com/media/en/technical-documentation/data-sheets/MAX3483-MAX3491.pdf) (17 pp, sha256 `e648fd27831d1ba1`, 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).

[Datasheet PDF](docs/max3485-datasheet.pdf)