MAX3221

@@ -0,0 +1,60 @@+# MAX3221++**Analog Devices** · RS-232 transceiver · SSOP-16++Single-channel RS-232 transceiver that runs the +/-5 V-class RS-232 line levels from a 3 to 5.5 V logic supply, using an on-chip charge pump (the C1/C2/V+/V- capacitor network) so no negative rail is needed. One driver (TTL in to RS-232 out) and one receiver (RS-232 in to TTL out) cover a basic serial port, and an auto-shutdown plus FORCEON/FORCEOFF and INVALID pins drop supply current when the line is idle. A compact 3.3 V-capable RS-232 front end for a single serial channel.++## Pinout++| Pin | Name | Type | Function |+|---|---|---|---|+| 1 | EN | input | Active-low receiver enable. Drive low for normal receiver operation; drive high to force R_OUT into high-Z. Logic threshold VIL=0.8V max, VIH=2.0V (3.3V) / 2.4V (5.0V). |+| 2 | C1+ | passive | Positive terminal of the voltage-doubler charge-pump flying capacitor (C1). Typ 0.1µF at 3.3V, 0.047µF at 5.0V (Note 2). |+| 3 | V+ | power_out | +5.5V output generated by the doubling charge pump. Bypass to GND with the reservoir capacitor C3 (0.1µF typ at 3.3V, 0.33µF at 5.0V). |+| 4 | C1- | passive | Negative terminal of the voltage-doubler charge-pump flying capacitor (C1). |+| 5 | C2+ | passive | Positive terminal of the inverting charge-pump flying capacitor (C2). Typ 0.1µF at 3.3V, 0.33µF at 5.0V. |+| 6 | C2- | passive | Negative terminal of the inverting charge-pump flying capacitor (C2). |+| 7 | V- | power_out | -5.5V output generated by the inverting charge pump. Bypass to GND with reservoir capacitor C4. |+| 8 | R_IN | input | RS-232 receiver input. Accepts ±25V EIA/TIA-232 levels; typical input resistance 5kΩ (3-7kΩ). VIL ≈ 0.6-1.2V, VIH ≈ 1.5-2.4V, 0.3V typical hysteresis. |+| 9 | R_OUT | tri_state | TTL/CMOS receiver output (inverted from R_IN). Three-state: high-Z in shutdown, when EN is high, or when the part is in AutoShutdown. VOL ≤ 0.4V at 1.6mA; VOH ≥ VCC-0.6V at -1.0mA. |+| 10 | INVALID | output | Active-low valid-signal detector output. Low (asserted) while all receiver inputs are between -0.3V and +0.3V for ≥30µs (invalid RS-232 present); high when a valid RS-232 level (>+2.7V or <-2.7V) appears. Useful for DTR/RI monitoring. |+| 11 | T_OUT | output | RS-232 transmitter output. Inverting driver to EIA/TIA-232 levels, ±5.0V typ swing into 3kΩ‖1000pF, short-circuit current ±35mA typ. High-Z in shutdown. |+| 12 | FORCEON | input | Active-high override that keeps the transmitter and charge pumps on regardless of receiver-input activity (FORCEOFF must be high). See AutoShutdown truth table. |+| 13 | T_IN | input | TTL/CMOS transmitter input. Drives the inverting RS-232 transmitter. VIL ≤ 0.8V, VIH ≥ 2.0V (3.3V) / 2.4V (5.0V). |+| 14 | GND | power_in | Device ground reference for logic and charge-pump return. |+| 15 | VCC | power_in | +3.0V to +5.5V supply input. Bypass with 0.1µF to GND. Absolute max -0.3V to +6V. |+| 16 | FORCEOFF | input | Active-low master shutdown. Drive low to disable transmitters and on-board power supply (overrides FORCEON and all AutoShutdown circuitry). Tie high for normal operation; can be tied to FORCEON as a single SHDN-style input. |++## Key specifications++| Parameter | Value |+|---|---|+| Type | RS-232 transceiver (1 driver, 1 receiver) |+| Supply | 3-5.5 V |+| Line levels | RS-232 via on-chip charge pump |+| Power control | Auto-shutdown, FORCEON / FORCEOFF |+| Status | INVALID (valid-signal detect) |+| Data rate | Up to 250 kbps |+| Package | SSOP-16 |++## Ordering variants++- `MAX3221CAE (SSOP-16)`+- `MAX3221IPWR (TSSOP-16)`+- `MAX3221EAE (+/-15 kV ESD)`++## CAD (KiCad official)++- Symbol: `Interface_UART:MAX3221 (KiCad official)`+- Footprint: `Package_SO:SSOP-16_5.3x6.2mm_P0.65mm`+- 3D model: SSOP-16 (KiCad packages3D, STEP)++## 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/MAX3221-MAX3243.pdf) (16 pp, sha256 `4b10ea08c7155060`, 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/max3221-datasheet.pdf)

@@ -0,0 +1,38 @@+{+  "slug": "max3221",+  "version": "0.1.0",+  "type": "component",+  "description": "ADI (Maxim) 1-driver 1-receiver RS-232 transceiver, SSOP-16. 3-5.5 V, charge-pump, auto-shutdown. Datasheet-verified.",+  "tags": [+    "component",+    "interface",+    "rs-232",+    "transceiver",+    "charge-pump",+    "ssop-16",+    "analog-devices"+  ],+  "dependencies": {},+  "hero": {+    "type": "image",+    "path": "docs/hero.png"+  },+  "files": [+    "page.json",+    "README.md",+    "max3221.kicad_sym",+    "max3221.kicad_mod",+    "max3221.glb",+    "max3221.step",+    "max3221.lbr",+    "docs/hero.png",+    "docs/max3221-datasheet.pdf",+    "viewers/symbol.html",+    "viewers/footprint.html"+  ],+  "visibility": "public",+  "author": {+    "name": "Ray",+    "email": "[email protected]"+  }+}\ No newline at end of file