MC74HC138ADTR2G from onsemi, 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	A0	input	Address input bit 0. Together with A1 and A2, selects which of the eight Y outputs is driven low when the chip is enabled.
2	A1	input	Address input bit 1. Together with A0 and A2, selects which of the eight Y outputs is driven low when the chip is enabled.
3	A2	input	Address input bit 2. Together with A0 and A1, selects which of the eight Y outputs is driven low when the chip is enabled.
4	CS2	input	Chip-select input 2 (active-low). Must be low, along with CS3 low and CS1 high, for the chip to be selected and outputs to follow the address inputs.
5	CS3	input	Chip-select input 3 (active-low). Must be low, along with CS2 low and CS1 high, for the chip to be selected and outputs to follow the address inputs.
6	CS1	input	Chip-select input 1 (active-high). Must be high, along with CS2 and CS3 low, for the chip to be selected and outputs to follow the address inputs.
7	Y7	output	Active-low decoded output 7. Drives low when address A2A1A0=111 and the chip is selected; otherwise remains high.
8	GND	power_in	Ground reference (0 V). Return for VCC supply and all logic signals.
9	Y6	output	Active-low decoded output 6. Drives low when address A2A1A0=110 and the chip is selected; otherwise remains high.
10	Y5	output	Active-low decoded output 5. Drives low when address A2A1A0=101 and the chip is selected; otherwise remains high.
11	Y4	output	Active-low decoded output 4. Drives low when address A2A1A0=100 and the chip is selected; otherwise remains high.
12	Y3	output	Active-low decoded output 3. Drives low when address A2A1A0=011 and the chip is selected; otherwise remains high.
13	Y2	output	Active-low decoded output 2. Drives low when address A2A1A0=010 and the chip is selected; otherwise remains high.
14	Y1	output	Active-low decoded output 1. Drives low when address A2A1A0=001 and the chip is selected; otherwise remains high.
15	Y0	output	Active-low decoded output 0. Drives low when address A2A1A0=000 and the chip is selected; otherwise remains high.
16	VCC	power_in	Positive supply voltage, 2.0 V to 6.0 V (referenced to GND). Absolute maximum 7.0 V.

Key specifications

Parameter	Value
Manufacturer	onsemi
Package	TSSOP-16
Category	Logic
Pins	16

Ordering variants

Same part, different packaging or reel option.

MC74HC138ADTR2G
MC74HC138ADTR2GNLV74HC138ADTR2G
MC74HC138ADTR2GDG
MC74HC138ADTR2GDR2G
MC74HC138ADG
MC74HC138ADR2G
MC74HC138ADTR2GNLV74HC138ADR2G
MC74HC138ADTR2GNG
MC74HC138ANG

CAD (KiCad official)

Symbol: MC74HC138ADTR2G
Footprint: Package_SO:TSSOP-16_4.4x5mm_P0.65mm
3D model: TSSOP-16 (KiCad packages3D, STEP)

Provenance

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

Datasheet: onsemi datasheet (10 pp, sha256 12975c730cca4e3e, 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