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74HC138PW

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

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جزء الشركة المصنعة ： جزء الشركة المصنعة

74HC138PW

الحزمة ： الحزمة

TSSOP-16 (5.0 x 4.4 x 1.0 mm)

الوصف

نظرة عامة على المنتج

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.

المواصفات الرئيسية

النوع	3-to-8 Line Decoder / Demultiplexer
الوظيفة	3-bit binary to 1-of-8 decoder, active LOW outputs
تأخير الانتشار	12 ns (typical @ 6V)
جهد الإمداد	2.0 V to 6.0 V (74HC)
Output Drive	+/-5.2 mA @ 6V
Enable Inputs	3 (2 active LOW, 1 active HIGH)
الحزمة	TSSOP-16 (4.4mm width)
درجة حرارة التشغيل	-40C to +125C

الميزات

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

التطبيقات

Memory address decoding
Data demultiplexing
Chip select generation
Clock distribution

مقدمة المنتج:74HC138PW مقدمة المنتج

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).

مبدأ العمل:74HC138PW مبدأ العمل

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.

وصف الدبوس:74HC138PW تعريف الدبوس ووظائفه

دبوس	الاسم	النوع	الوظيفة
1	A0	المدخلات	Address input bit 0 (LSB)
2	A1	المدخلات	Address input bit 1
3	A2	المدخلات	Address input bit 2 (MSB)
4	E1	المدخلات	Enable input (active LOW)
5	E2	المدخلات	Enable input (active LOW)
6	E3	المدخلات	Enable input (active HIGH)
7-9	Y7-Y5	المخرجات	Decoded outputs (active LOW)
10	GND	الطاقة	أرضي
11-13	Y4-Y2	المخرجات	Decoded outputs (active LOW)
14	Y1	المخرجات	Decoded output (active LOW)
15	Y0	المخرجات	Decoded output (active LOW)
16	VCC	الطاقة	Supply (2-6V)

Application Scenarios:In which products and applications is74HC138PW مستعمل

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

الشركة المصنعة	رقم الجزء	الحزمة	الملاحظات
نيكسبيريا	74HC138PW,118	TSSOP-16	Full Nexperia ordering code (same device)
TI	SN74HC138PWR	TSSOP-16	Pin-compatible TI equivalent
أونسمي	MC74HC138ADR2G	SOIC-16	Same function, SOIC package
نيكسبيريا	74HC238PW,118	TSSOP-16	Same but active HIGH outputs
نيكسبيريا	74HC154D,653	SOIC-24	4-to-16 decoder, larger function