SP3243EUEA-L from MaxLinear, in a SSOP-28-208mil. 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	C2+	passive	Positive terminal of the inverting charge-pump flying capacitor (C2 = 0.1µF between C2+ and C2-).
2	C2-	passive	Negative terminal of the inverting charge-pump flying capacitor.
3	V-	power_out	Regulated -5.5V output generated by the internal charge pump. Bypass with a 0.1µF capacitor to GND.
4	R1IN	input	RS-232 receiver 1 input (±25V tolerant). Internally pulled to GND through ~5kΩ. Accepts RS-232 line levels and produces a TTL/CMOS level on R1OUT.
5	R2IN	input	RS-232 receiver 2 input. Complementary always-active receiver - its /R2OUT stays alert during shutdown to monitor an external device (e.g. modem Ring Indicate).
6	R3IN	input	RS-232 receiver 3 input (±25V tolerant, ~5kΩ to GND).
7	R4IN	input	RS-232 receiver 4 input (±25V tolerant, ~5kΩ to GND).
8	R5IN	input	RS-232 receiver 5 input (±25V tolerant, ~5kΩ to GND).
9	T1OUT	output	RS-232 driver 1 output - ±5V-class RS-232 line driver output, slew-rate limited. High-impedance in shutdown.
10	T2OUT	output	RS-232 driver 2 output.
11	T3OUT	output	RS-232 driver 3 output.
12	T3IN	input	TTL/CMOS driver 3 input.
13	T2IN	input	TTL/CMOS driver 2 input.
14	T1IN	input	TTL/CMOS driver 1 input.
15	R5OUT	output	TTL/CMOS receiver 5 output. High-impedance in shutdown.
16	R4OUT	output	TTL/CMOS receiver 4 output.
17	R3OUT	output	TTL/CMOS receiver 3 output.
18	R2OUT	output	TTL/CMOS receiver 2 output (main, tri-stated in shutdown).
19	R1OUT	output	TTL/CMOS receiver 1 output. High-impedance in shutdown.
20	/R2OUT	output	Non-inverting complementary R2 output that remains active in shutdown - used to monitor an external device (e.g. modem Ring Indicate) while the transceiver is powered down.
21	/STATUS	output	TTL/CMOS status output indicating online and shutdown state of the transceiver. Drives a microprocessor supervisory circuit.
22	/SHUTDOWN	input	Active-low shutdown input. Logic LOW disables drivers and charge pump (Icc drops to <1µA); overrides AUTO ON-LINE and /ONLINE. Tie to VCC for normal operation.
23	/ONLINE	input	Active-low ONLINE input. Logic HIGH overrides AUTO ON-LINE circuitry and keeps the drivers active (with /SHUTDOWN also HIGH). Logic LOW re-enables AUTO ON-LINE operation.
24	C1-	passive	Negative terminal of the voltage-doubler charge-pump flying capacitor (C1 = 0.1µF between C1+ and C1-).
25	GND	power_in	Device ground reference.
26	VCC	power_in	Positive supply, +3.0V to +5.5V. Bypass with 0.1µF to GND.
27	V+	power_out	Regulated +5.5V output generated by the internal charge pump. Bypass with a 0.1µF capacitor to GND.
28	C1+	passive	Positive terminal of the voltage-doubler charge-pump flying capacitor.

Key specifications

Parameter	Value
Manufacturer	MaxLinear
Package	SSOP-28-208mil
Category	Interface
Pins	28

Ordering variants

Same part, different packaging or reel option.

SP3243EUEA-L/TR
SP3243EEA-L
SP3243EEA-L/TR
SP3243ECA-L
SP3243ECA-L/TR
SP3243EBEA-L/TR
SP3243EHEA-L/TR
SP3243EUCA-L/TR
SP3243EBCA-L/TR
SP3243EHCA-L/TR
SP3243EUEY-L/TR
SP3243EEY-L
SP3243EEY-L/TR
SP3243ECY-L/TR
SP3243EBEY-L
SP3243EBEY-L/TR
SP3243EBCY-L/TR
SP3243EUCY-L/TR
SP3243EUER-L/TR

CAD (KiCad official)

Symbol: SP3243EUEA-L
Footprint: Package_SO:SSOP-28_5.3x10.2mm_P0.65mm
3D model: SSOP-28-208mil (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`sp3243euea-l.step`	362 KB	You want the bare part, or you mark your own boards.
`sp3243euea-l-etched.step`	3.3 MB	You want the part with `SP3243EUEA-L` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 838 faces against 447 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: MaxLinear datasheet (30 pp, sha256 ee87c4d95d30c448, 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