74LCX245MTCX from onsemi, 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	T/R	input	Transmit/Receive input. Determines the direction of data flow: LOW routes B->A, HIGH routes A->B (when OE is LOW).
2	A0	bidirectional	Side A bidirectional bus pin 0. Acts as input when T/R=H, or 3-STATE output when T/R=L (with OE=L). High-Z when OE=H. 5V tolerant.
3	A1	bidirectional	Side A bidirectional bus pin 1. Acts as input when T/R=H, or 3-STATE output when T/R=L (with OE=L). 5V tolerant.
4	A2	bidirectional	Side A bidirectional bus pin 2. Acts as input when T/R=H, or 3-STATE output when T/R=L (with OE=L). 5V tolerant.
5	A3	bidirectional	Side A bidirectional bus pin 3. Acts as input when T/R=H, or 3-STATE output when T/R=L (with OE=L). 5V tolerant.
6	A4	bidirectional	Side A bidirectional bus pin 4. Acts as input when T/R=H, or 3-STATE output when T/R=L (with OE=L). 5V tolerant.
7	A5	bidirectional	Side A bidirectional bus pin 5. Acts as input when T/R=H, or 3-STATE output when T/R=L (with OE=L). 5V tolerant.
8	A6	bidirectional	Side A bidirectional bus pin 6. Acts as input when T/R=H, or 3-STATE output when T/R=L (with OE=L). 5V tolerant.
9	A7	bidirectional	Side A bidirectional bus pin 7. Acts as input when T/R=H, or 3-STATE output when T/R=L (with OE=L). 5V tolerant.
10	GND	power_in	Ground reference (0V). Return for all supply and I/O currents.
11	B7	bidirectional	Side B bidirectional bus pin 7. Acts as input when T/R=L, or 3-STATE output when T/R=H (with OE=L). 5V tolerant.
12	B6	bidirectional	Side B bidirectional bus pin 6. Acts as input when T/R=L, or 3-STATE output when T/R=H (with OE=L). 5V tolerant.
13	B5	bidirectional	Side B bidirectional bus pin 5. Acts as input when T/R=L, or 3-STATE output when T/R=H (with OE=L). 5V tolerant.
14	B4	bidirectional	Side B bidirectional bus pin 4. Acts as input when T/R=L, or 3-STATE output when T/R=H (with OE=L). 5V tolerant.
15	B3	bidirectional	Side B bidirectional bus pin 3. Acts as input when T/R=L, or 3-STATE output when T/R=H (with OE=L). 5V tolerant.
16	B2	bidirectional	Side B bidirectional bus pin 2. Acts as input when T/R=L, or 3-STATE output when T/R=H (with OE=L). 5V tolerant.
17	B1	bidirectional	Side B bidirectional bus pin 1. Acts as input when T/R=L, or 3-STATE output when T/R=H (with OE=L). 5V tolerant.
18	B0	bidirectional	Side B bidirectional bus pin 0. Acts as input when T/R=L, or 3-STATE output when T/R=H (with OE=L). 5V tolerant.
19	OE	input	Output Enable input (active LOW). When HIGH, both A and B ports are forced to high-impedance (3-STATE). To ensure high-Z during power-up/down, tie OE to VCC through a pull-up resistor.
20	VCC	power_in	Positive supply voltage. Operating range 2.0V to 3.6V (recommended), data retention 1.5V to 3.6V. Absolute max -0.5V to +7.0V. Inputs/outputs are 5V tolerant.

Key specifications

Parameter	Value
Manufacturer	onsemi
Package	TSSOP-20
Category	Logic
Pins	20

Ordering variants

Same part, different packaging or reel option.

74LCX245MTCX
74LCX245MTCX_NL
74LCX245MTCXWM
74LCX245MTCXWMX_NL
74LCX245MTCXSJ
74LCX245MTCXMSA
74LCX245MTCXBQX

CAD (KiCad official)

Symbol: 74LCX245MTCX
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: onsemi datasheet (12 pp, sha256 5d4f8993e360a70a, 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