MAX3221EIPWR from Texas Instruments, in a TSSOP-16. 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	EN	input	Active-low receiver enable input. Low input enables the receiver ROUT output; high input sets ROUT to high impedance.
2	C1+	passive	Positive terminal of the voltage-doubler charge-pump capacitor C1. Connect a 0.1 µF (VCC=3.3V) or 0.047 µF (VCC=5V) capacitor between C1+ and C1-.
3	V+	power_out	+5.5-V supply rail generated by the internal charge pump. Requires an external reservoir capacitor to GND.
4	C1-	passive	Negative terminal of the voltage-doubler charge-pump capacitor C1. Paired with C1+.
5	C2+	passive	Positive terminal of the voltage-inverter charge-pump capacitor C2. Connect a 0.1 µF or 0.33 µF capacitor between C2+ and C2-.
6	C2-	passive	Negative terminal of the voltage-inverter charge-pump capacitor C2. Paired with C2+.
7	V-	power_out	-5.5-V supply rail generated by the internal charge-pump inverter. Requires an external reservoir capacitor to GND.
8	RIN	input	RS-232 receiver input. Accepts ±25-V RS-232 signaling levels and provides ±15-kV IEC 61000-4-2 ESD protection.
9	ROUT	output	Receiver output (TTL/CMOS-level). Driven by RIN; goes to high impedance when EN is high.
10	INVALID	output	Invalid output status pin (active-low). Output is low when the RIN input is unpowered or disconnected, indicating no valid RS-232 signal.
11	DIN	input	Driver (transmitter) input. Accepts TTL/CMOS logic levels (compatible with 3.3-V or 5-V logic).
12	FORCEON	input	Auto-power-down control input. Together with FORCEOFF, selects automatic or manual driver enable behavior.
13	DOUT	output	RS-232 driver output. Delivers ±5-V typical RS-232 signaling levels with ±15-kV IEC 61000-4-2 ESD protection and up to 30-V/µs slew rate.
14	GND	power_in	Device ground reference.
15	VCC	power_in	3-V to 5.5-V primary supply voltage. Bypass with a 0.1 µF capacitor to GND.
16	FORCEOFF	input	Active-low auto-power-down control input. When low, forces the driver and charge pump off for power savings; when high, allows normal or auto-power-down operation with FORCEON.

Key specifications

Parameter	Value
Manufacturer	Texas Instruments
Package	TSSOP-16
Category	Interface
Pins	16

Ordering variants

Same part, different packaging or reel option.

MAX3221EIPWR
MAX3221EIPWRECPW
MAX3221EIPWRECPWR
MAX3221EIPWRIDB
MAX3221EIPWRIDBR
MAX3221EIPWRECDB
MAX3221EIPWRECDBR

CAD (KiCad official)

Symbol: MAX3221EIPWR
Footprint: Package_SO:TSSOP-16_4.4x5mm_P0.65mm
3D model: TSSOP-16 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`max3221eipwr.step`	205 KB	You want the bare part, or you mark your own boards.
`max3221eipwr-etched.step`	2.5 MB	You want the part with `MAX3221EIPWR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 650 faces against 255 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

Datasheet: Texas Instruments datasheet (26 pp, sha256 6fab784842148401, 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