NTE74LS08 - Quad 2-Input AND Gate, TTL LS, DIP-14 | NTE Electronics
N.º da peça: NTE74LS08 ✗ Fim de vida| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $0.55 | $0,55 |
| 10 | $0.48 | $4,80 |
| 100 | $0.38 | $38,00 |
| 500 | $0.3 | $150,00 |
| 1.000 | $0.24 | $240,00 |
NTE74LS08 Visão geral
A quad AND gate is a combinational logic device whose output goes HIGH only when both of its inputs are HIGH; the 'quad 2-input' designation means the package integrates four such gates sharing only power and ground. AND gates form the foundation of digital logic hierarchy, sitting alongside NAND, OR, and NOT gates within the broader transistor-transistor logic (TTL) family and the wider class of small-scale integration (SSI) logic ICs.
Key features of the NTE74LS08 include Low-Power Schottky (LS) process technology, which uses Schottky-clamped transistors to combine the speed of standard TTL with significantly reduced power consumption, a commercial temperature grade suitable for bench and service environments, and through-hole mounting ideal for prototyping, breadboarding, and repair work. Each gate output sinks and sources current compatible with other TTL and many CMOS loads.
Architecturally, the LS family's Schottky diode clamping prevents transistor saturation, cutting storage time and enabling propagation delays around 20 ns while keeping per-gate power draw low relative to standard 7400-series TTL. The NTE74LS08 is NTE Electronics' direct replacement numbering for the industry-standard 74LS08 function, widely used in maintenance, repair, and overhaul (MRO) contexts.
Typical applications include legacy industrial control logic, address decoding in vintage computing and test equipment, signal interlock and enable-gating circuits in instrumentation, and educational digital logic laboratory work. The through-hole DIP-14 package makes it especially well suited to socketed replacements on older PCBs.
A key design consideration: as a bipolar TTL device, unused inputs should not be left floating - tie them to VCC through a 1 kOhm to 10 kOhm resistor or to a driven output to avoid noise-induced oscillation.
This page synthesizes distributor pricing, drop-in alternatives, a full DIP-14 pinout, and practical design notes not found in the manufacturer datasheet. Note that NTE Electronics permanently closed operations in late 2024, so stock is available only through remaining distributor and excess inventory channels; the industry-standard equivalents listed here are the recommended path for new designs.
Alternativas drop-in para NTE74LS08 — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
NTE74LS09
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
SN74LS08N
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
SN74HC08N
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
HD74LS08P
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
SN74LS08N
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
NTE74LS08 Classificações máximas e características elétricas
| Função | Quad 2-Input Positive AND Gate |
| Logic Family | Low-Power Schottky TTL (74LS) |
| Number of Gates | 4 |
| Inputs per Gate | 2 |
| Supply Voltage Range | 4.75 V to 5.25 V |
| Nominal Supply Voltage | 5 V |
| Output Current | 8.8 mA |
| Propagation Delay | 20 ns at 5 V, 15 pF load |
| Technology | Transistor Transistor Logic (TTL) |
| Encapsulamento | 14-Lead Plastic DIP (PDIP-14) |
| Tipo de montagem | Through-Hole |
| Number of Terminals | 14 |
| Temperature Grade | Commercial (0C to +70C) |
| Status RoHS | Compliant |
| Package Shape | Rectangular |
| Manufacturer Status | NTE Electronics ceased operations in late 2024 |
Configuração de pinos do NTE74LS08
| Pino 1 | 1A — Gate 1 input A |
| Pino 2 | 1B — Gate 1 input B |
| Pino 3 | 1Y — Gate 1 output (HIGH when 1A AND 1B are HIGH) |
| Pino 4 | 2A — Gate 2 input A |
| Pino 5 | 2B — Gate 2 input B |
| Pino 6 | 2Y — Gate 2 output (HIGH when 2A AND 2B are HIGH) |
| Pino 7 | GND — Ground |
| Pino 8 | 3Y — Gate 3 output (HIGH when 3A AND 3B are HIGH) |
| Pino 9 | 3A — Gate 3 input A |
| Pino 10 | 3B — Gate 3 input B |
| Pino 11 | 4Y — Gate 4 output (HIGH when 4A AND 4B are HIGH) |
| Pino 12 | 4A — Gate 4 input A |
| Pino 13 | 4B — Gate 4 input B |
| Pino 14 | VCC — Positive supply, 4.75 V to 5.25 V |
Aplicações típicas
NTE74LS08 é adequado para 6 aplicaçãos: Address Decoding in Legacy Systems, Industrial Interlock and Enable Logic, Signal Gating in Test and Measurement Equipment, Educational Digital Logic Laboratories, Clock and Pulse Qualification Circuits, MRO and Obsolete-Stock Replacement.
Address Decoding in Legacy Systems
AND gates are the workhorse of address decoding in vintage computers, microprocessor trainers, and legacy industrial controllers built on 8-bit buses. The NTE74LS08's four independent 2-input gates let a single DIP-14 package qualify address-bit combinations to generate chip-select and memory-mapping signals. With a 20 ns propagation delay at 5V, decode timing comfortably fits within the access windows of 6800, Z80, and 6502-class systems, while the 8.8 mA output drive meets TTL bus loading rules. In repair work on socketed decoder sections, any standard 74LS08 drops straight into the same 14-pin DIP socket, making the NTE74LS08 and its equivalents the natural maintenance part for boards where the original silk-screen calls out 74LS08 or NTE numbering.
Recomendado
Industrial Interlock and Enable Logic
Safety interlocks and enable gating in legacy industrial machinery frequently use AND gates to combine status signals: a drive enable, a guard-closed input, and a ready flag must all be HIGH before power is released. The NTE74LS08 suits this role because its bipolar TTL inputs offer robust, well-defined thresholds on 5V rails common in PLC-adjacent control cabinets, and its commercial temperature grade covers typical cabinet environments. The through-hole DIP-14 package is socket-mountable, so field technicians can replace a failed gate in minutes without hot-air tools. Designers should remember that AND-based interlocks are logic-level features only; certified functional-safety applications require appropriate rated safety relays or controllers, with the 74LS08 serving supplementary monitoring and status logic.
Recomendado
Signal Gating in Test and Measurement Equipment
Bench instruments such as frequency counters, event counters, and older oscilloscope trigger circuits use AND gates to gate counting windows and qualify trigger conditions. The NTE74LS08's 20 ns propagation delay (5V, 15 pF) supports gating at tens of megahertz, adequate for classic instrument architectures, while Low-Power Schottky technology keeps supply current modest in dense gate arrays. The TTL input structure presents predictable loading to instrument front ends that were designed for LS fan-out rules. When restoring or repairing such instruments, the DIP-14 socketed NTE74LS08 (or any standard 74LS08) is a direct replacement; keep a 100 nF decoupling capacitor at the socket to prevent ground-bounce glitches in high-count-rate circuits.
Recomendado
Educational Digital Logic Laboratories
University and vocational digital electronics labs teach Boolean logic on breadboards using through-hole 7400-series ICs, and the quad 2-input AND gate is a core experiment device. The NTE74LS08's DIP-14 through-hole package plugs directly into solderless breadboards and wire-wrap panels, and its 5V supply matches standard lab bench supplies. Students verify the AND truth table, cascade gates to build multi-input functions, and observe 20 ns propagation delays on bench oscilloscopes. Because NTE ceased production in late 2024, lab stockrooms should standardize on active 74LS08 or 74HC08 equivalents, which share the identical pinout so experiment worksheets remain valid across all sourcing. Bulk tube packaging keeps per-student cost low for class sets.
Recomendado
Clock and Pulse Qualification Circuits
Combining a clock or pulse train with a qualifier signal - gating the count, masking a window, or arming a one-shot - is a classic AND-gate role in legacy timing chains. The NTE74LS08's LS-TTL switching gives fast, symmetric rise and fall behavior on 5V rails, and its 8.8 mA drive handles typical TTL clock distribution loads of a few LS gates plus wiring capacitance. In repair of equipment from the TTL era, replacing a gated-clock stage with a socketed 74LS08-class device preserves original timing margins exactly, since all second sources meet the same 20 ns specification. Designers adding new gating to LS systems should budget propagation delay of each AND stage into worst-case setup and hold analysis.
Recomendado
MRO and Obsolete-Stock Replacement
Maintenance, repair, and overhaul of equipment built between the late 1970s and 2000s frequently encounters boards annotated with NTE part numbers or generic 74LS08 references. The NTE74LS08 existed precisely for this service market as a house-numbered standard-function device. With NTE Electronics closed since late 2024, remaining NTE74LS08 inventory is finite, so MRO organizations should qualify the pin-identical industry-standard 74LS08 equivalents now: same DIP-14 footprint, same 4.75V-5.25V supply window, same 20 ns timing. Stocking standard 74LS08 tubes instead of chasing NTE-branded residual stock eliminates obsolescence risk while guaranteeing functional and mechanical interchangeability in every socketed application.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para NTE74LS08 — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | NTE74LS09 | SN74LS08N (TI) | SN74HC08N (TI) | HD74LS08P |
|---|---|---|---|---|---|
| Package | PDIP-14 | PDIP-14 - same | PDIP-14 - same | PDIP-14 - same | PDIP-14 - same |
| Brand | NTE Electronics (closed late 2024) | NTE Electronics (closed late 2024) | Texas Instruments - active | Texas Instruments - active | Renesas Electronics |
| Function | Quad 2-Input AND (totem-pole outputs) | Quad 2-Input AND, open-collector outputs | Quad 2-Input AND (totem-pole outputs) | Quad 2-Input AND (CMOS) | Quad 2-Input AND (totem-pole outputs) |
| Supply Voltage | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 2 V to 6 V | 4.75 V to 5.25 V |
| Technology | Low-Power Schottky TTL | Low-Power Schottky TTL | Low-Power Schottky TTL | High-Speed CMOS | Low-Power Schottky TTL |
| Lifecycle Status | Obsolete (NTE ceased operations late 2024) | Obsolete (NTE ceased operations late 2024) | Active | Active | Active / mature |
Principais diferenciais
- Bipolar TTL thresholds for legacy-system fidelity (vs SN74HC08N)
- Open-collector AND option in same family (vs NTE74LS09)
- Active-production security via standard equivalents (vs SN74LS08N)
Notas de projeto
Never leave NTE74LS08 inputs floating. Bipolar LS-TTL inputs left unconnected float near the logic threshold, picking up noise and causing erratic gate outputs. Tie unused inputs to VCC through a 1 kOhm to 10 kOhm pull-up resistor or drive them from a logic output. Unused gate outputs may be left open. This is the single most common cause of intermittent failures in legacy TTL repair work, where a floating gate appears to work until board temperature or humidity shifts.
Decouple VCC (pin 14) with a 100 nF ceramic capacitor placed within a few millimeters of the package, plus 10 uF bulk capacitance per board region. LS-TTL outputs draw sharp current spikes during totem-pole switching transitions, and without local decoupling these spikes appear as supply glitches that can falsely clock adjacent flip-flops. On dense TTL boards, allocate one 100 nF capacitor per IC and route the 5V rail as a low-impedance plane or wide trace to limit rail droop during simultaneous switching.
When substituting NTE74LS08 in legacy sockets, inspect socket contacts before insertion - many 40-year-old DIP sockets have oxidized or fatigued beryllium-copper clips that cause high-resistance connections mimicking gate failure. Clean contacts with contact cleaner and verify 5V at pin 14 and continuity at pin 7 under load. Because any industry-standard 74LS08 shares the exact DIP-14 footprint and pinout, substitution requires no PCB rework, only attention to static-sensitive handling during through-hole insertion.
Informações de conformidade
Distributor listing (onlinecomponents.com) states RoHS Compliant for the 14-lead plastic DIP package. NTE Electronics closed operations in late 2024; its compliance database is offline, so REACH, lead-free, halogen-free, and conflict-minerals status cannot be verified from current sources.
