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74HC138PW

3-to-8 Decoder/Demux, Active LOW Out, TSSOP-16, 74HC

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Pieza del fabricante：

74HC138PW

Paquete：

TSSOP-16 (5.0 x 4.4 x 1.0 mm)

Descripción

Productos

The 74HC138PW is a 3-to-8 line decoder/demultiplexer with inverting outputs, designed for memory decoding and data routing applications in a TSSOP-16 package.

Especificaciones

Tipo	3-to-8 Line Decoder / Demultiplexer
Función	3-bit binary to 1-of-8 decoder, active LOW outputs
Retardo de propagación	12 ns (typical @ 6V)
Tensión de alimentación	2.0 V to 6.0 V (74HC)
Output Drive	+/-5.2 mA @ 6V
Enable Inputs	3 (2 active LOW, 1 active HIGH)
Paquete	TSSOP-16 (4.4mm width)
Temperatura de funcionamiento	-40C to +125C

Características

3-to-8 decoder with active LOW outputs
3 enable inputs for expansion capability
12 ns typical propagation delay
2V to 6V supply range
Memory address decoding
Demultiplexing capability

Aplicaciones

Memory address decoding
Data demultiplexing
Chip select generation
Clock distribution

Introducción del producto:74HC138PW Presentación del producto

The 74HC138PW is a high-speed CMOS 3-to-8 line decoder/demultiplexer with active LOW outputs. The device accepts a 3-bit binary address (A0, A1, A2) and activates one of eight mutually exclusive outputs (Y0 to Y7). Three enable inputs (two active LOW E1, E2 and one active HIGH E3) facilitate expansion to larger decoder configurations: four 74HC138 devices plus one inverter can implement a 1-of-32 decoder. The device is widely used for memory address decoding, chip select generation, and data demultiplexing in digital systems. The TSSOP-16 package provides a compact footprint for modern PCB designs. Note: This model number without manufacturer-specific ordering suffix is a generic 74HC138PW listing; the Nexperia version with full ordering code 74HC138PW,118 was already published in Group 6 (Article ID 6788).

Principio de funcionamiento:74HC138PW Principio de funcionamiento

The 74HC138PW uses internal NAND gates to decode the 3-bit address. Each output Y(n) is activated (driven LOW) when the address inputs match the binary value n (0-7) AND all enable conditions are met (E1=LOW, E2=LOW, E3=HIGH). If any enable condition is not satisfied, all outputs remain HIGH (inactive). The propagation delay of approximately 12 ns at 6V is determined by the two levels of logic gates between the address inputs and outputs. The enable inputs serve dual purposes: they prevent glitching during address transitions (by disabling the outputs during the transition), and they allow cascading for address expansion. In demultiplexer mode, the data input is applied to one of the enable inputs (typically E3), and the address selects which output receives the data. The active LOW outputs are directly compatible with active LOW chip select inputs on memory and peripheral ICs.

Descripción de la clavija:74HC138PW Definición y funciones de las clavijas

Pin	Nombre	Tipo	Función
1	A0	Entrada	Address input bit 0 (LSB)
2	A1	Entrada	Address input bit 1
3	A2	Entrada	Address input bit 2 (MSB)
4	E1	Entrada	Enable input (active LOW)
5	E2	Entrada	Enable input (active LOW)
6	E3	Entrada	Enable input (active HIGH)
7-9	Y7-Y5	Salida	Decoded outputs (active LOW)
10	GND	Potencia	Suelo
11-13	Y4-Y2	Salida	Decoded outputs (active LOW)
14	Y1	Salida	Decoded output (active LOW)
15	Y0	Salida	Decoded output (active LOW)
16	VCC	Potencia	Supply (2-6V)

Application Scenarios:In which products and applications is74HC138PW usado

8-device chip select decoder from 3-bit MCU address bus
Memory bank selection using 2 enable inputs for 4-bank expansion
Clock distribution demultiplexer routing clock to 1 of 8 destinations
1-of-32 decoder using 4x 74HC138 + 1 inverter for 5-bit address

Alternative Models:What chips are recommended as replacements for 74HC138PW

Fabricante	Número de pieza	Paquete	Notas
Nexperia	74HC138PW,118	TSSOP-16	Full Nexperia ordering code (same device)
TI	SN74HC138PWR	TSSOP-16	Pin-compatible TI equivalent
onsemi	MC74HC138ADR2G	SOIC-16	Same function, SOIC package
Nexperia	74HC238PW,118	TSSOP-16	Same but active HIGH outputs
Nexperia	74HC154D,653	SOIC-24	4-to-16 decoder, larger function