COSMAX3222 from COSINE, in a TSSOP-20. 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	Receiver Enable (active-LOW, EN\overline). Drive LOW for normal receiver operation; drive HIGH to place receiver outputs in high-impedance (tri-state).
2	C1+	passive	Positive terminal of the voltage-doubler charge-pump flying capacitor (C1, typ. 0.1 uF).
3	V+	power_out	+5.5 V output generated by the internal charge pump. Bypass to GND with a 0.1 uF capacitor (C3).
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. 0.1 uF).
6	C2-	passive	Negative terminal of the inverting charge-pump flying capacitor (C2).
7	V-	power_out	-5.5 V output generated by the internal inverting charge pump. Bypass to GND with a 0.1 uF capacitor (C4).
8	T2OUT	output	RS-232 driver #2 output. Inverted RS-232-level (nominally +/-5 V) transmit line for connection to the serial port.
9	R2IN	input	RS-232 receiver #2 input. Accepts +/-15 V RS-232 signaling from the serial port; internal 5 kOhm pulldown commits output HIGH when input is open.
10	R2OUT	tri_state	TTL/CMOS receiver #2 output. Inverted logic-level output of receiver 2; tri-stated when EN\overline is HIGH.
11	NC	unconnected	No internal connection. Leave floating or tie to GND.
12	T2IN	input	TTL/CMOS driver #2 input. Must be a valid HIGH or LOW; no internal pullup, so unused inputs should be tied to VCC or GND.
13	T1IN	input	TTL/CMOS driver #1 input. Must be a valid HIGH or LOW; no internal pullup, so unused inputs should be tied to VCC or GND.
14	NC	unconnected	No internal connection. Leave floating or tie to GND.
15	R1OUT	tri_state	TTL/CMOS receiver #1 output. Inverted logic-level output of receiver 1; tri-stated when EN\overline is HIGH.
16	R1IN	input	RS-232 receiver #1 input. Accepts +/-15 V RS-232 signaling from the serial port; internal 5 kOhm pulldown commits output HIGH when input is open.
17	T1OUT	output	RS-232 driver #1 output. Inverted RS-232-level (nominally +/-5 V) transmit line for connection to the serial port.
18	GND	power_in	Device ground / 0 V reference.
19	VCC	power_in	Positive supply, 3.0 V to 5.5 V. Bypass to GND with a 0.1 uF capacitor.
20	SHDN	input	Shutdown control input (active-LOW, SHDN\overline). Drive HIGH for normal device operation. Drive LOW to shut down the drivers (high-Z outputs) and disable the on-chip charge pumps; supply current falls below 1 uA.

Key specifications

Parameter	Value
Manufacturer	COSINE
Package	TSSOP-20
Category	Interface
Pins	20

Ordering variants

Same part, different packaging or reel option.

COSMAX3222SR
COSMAX3222

CAD (KiCad official)

Symbol: COSMAX3222
Footprint: Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm
3D model: TSSOP-20 (KiCad packages3D, STEP)

Provenance

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

Datasheet: COSINE datasheet (11 pp, sha256 fb0a0d94b62f6d61, retrieved 2026-08-17, tier: lcsc)
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