ST232CDR from STMicroelectronics, in a SOIC-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	C1+	passive	Positive terminal for the first charge pump capacitor (voltage doubler). Connect a 0.1 µF capacitor between C1+ and C1- (pin 3).
2	V+	power_out	Doubled voltage terminal, approximately +10 V generated by the internal charge pump. Bypass to GND with a 0.1 µF capacitor.
3	C1-	passive	Negative terminal for the first charge pump capacitor (voltage doubler). Connect a 0.1 µF capacitor between C1+ (pin 1) and C1-.
4	C2+	passive	Positive terminal for the second charge pump capacitor (voltage inverter). Connect a 0.1 µF capacitor between C2+ and C2- (pin 5).
5	C2-	passive	Negative terminal for the second charge pump capacitor (voltage inverter). Connect a 0.1 µF capacitor between C2+ (pin 4) and C2-.
6	V-	power_out	Inverted voltage terminal, approximately -10 V generated by the internal charge pump. Bypass to GND with a 0.1 µF capacitor.
7	T2OUT	output	Second transmitter (driver) RS-232 output. Swings typically ±7.8 V into a 3 kΩ load; short-circuit current typ ±10 mA (max ±60 mA).
8	R2IN	input	Second receiver RS-232 input. Accepts ±30 V; input resistance 3-7 kΩ (typ 5 kΩ); logic thresholds VRIL=1.2 V typ / VRIH=1.7 V typ with 0.5 V typ hysteresis.
9	R2OUT	output	Second receiver TTL/CMOS output. VOL ≤ 0.4 V at 3.2 mA sink; VOH ≥ 3.5 V at 1 mA source.
10	T2IN	input	Second transmitter (driver) TTL/CMOS input. Logic threshold low 0.8 V max, high 2 V min; internally pulled up (~400 kΩ) to VCC per typical application.
11	T1IN	input	First transmitter (driver) TTL/CMOS input. Logic threshold low 0.8 V max, high 2 V min; internally pulled up (~400 kΩ) to VCC per typical application.
12	R1OUT	output	First receiver TTL/CMOS output. VOL ≤ 0.4 V at 3.2 mA sink; VOH ≥ 3.5 V at 1 mA source.
13	R1IN	input	First receiver RS-232 input. Accepts ±30 V; input resistance 3-7 kΩ (typ 5 kΩ); logic thresholds VRIL=1.2 V typ / VRIH=1.7 V typ with 0.5 V typ hysteresis.
14	T1OUT	output	First transmitter (driver) RS-232 output. Swings typically ±7.8 V into a 3 kΩ load; short-circuit current typ ±10 mA (max ±60 mA).
15	GND	power_in	Device ground reference (0 V) for logic-side and charge-pump return.
16	VCC	power_in	Positive supply voltage. Operating range 4.5 to 5.5 V; supply current 5 mA typ (10 mA max) no-load. Bypass to GND with a 0.1 µF capacitor.

Key specifications

Parameter	Value
Manufacturer	STMicroelectronics
Package	SOIC-16
Category	Interface
Pins	16

Ordering variants

Same part, different packaging or reel option.

ST232CN
ST232CDR
ST232BDR
ST232CWR
ST232BWR
ST232CTR
ST232BTR

CAD (KiCad official)

Symbol: ST232CDR
Footprint: Package_SO:SOIC-16_3.9x9.9mm_P1.27mm
3D model: SOIC-16 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`st232cdr.step`	217 KB	You want the bare part, or you mark your own boards.
`st232cdr-etched.step`	2.4 MB	You want the part with `ST232CDR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 585 faces against 267 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: STMicroelectronics datasheet (19 pp, sha256 2affe3b6692a2dbb, 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