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Texas Instruments SN74LS33NG4
- Part No.:
- SN74LS33NG4
- Manufacturer:
- Texas Instruments
- Category:
- Gates and Inverters
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74LS33NG4.pdf
- Description:
- IC GATE NOR 4CH 2-INP 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,677
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Product details
Overview
SN74LS33NG4 from Texas Instruments is a quad 2-input NAND gate with open-collector outputs, designed for wired-AND logic, level translation, and bus interface applications in TTL-compatible digital systems. It operates from 4.75 V to 5.25 V, supports fan-out of 20 LS-TTL loads, delivers output sink current up to 24 mA, and functions across 0°C to 70°C ambient temperature.
For engineers reviewing the SN74LS33NG4 datasheet, SN74LS33NG4 pinout, SN74LS33NG4 application, or SN74LS33NG4 equivalent, key selection considerations include its open-collector architecture, TTL input compatibility, guaranteed high-voltage off-state isolation, and PDIP-14 package suitability for prototyping and industrial control boards.
Technical Context
The SN74LS33NG4 implements four independent NAND gates, each with an open-collector output stage enabling direct wired-AND connection without external pull-ups. Its inputs are compatible with standard TTL logic levels, and the output can drive loads referenced to voltages up to 15 V via external pull-up.
This device belongs to the 74LS logic family and shares propagation delay (tPLH/tPHL) of 15 ns typical at VCC = 5 V and load capacitance = 15 pF, with input clamp diodes providing transient protection and defined low-level input voltage threshold (VIL) ≤ 0.8 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS - Low-power Schottky TTL, ensuring compatibility with legacy TTL systems and reduced power vs. standard 74-series. |
| Supply Voltage | 4.75 V to 5.25 V - Tight regulation required; operation outside this range risks undefined logic states or reliability degradation. |
| Output Type | Open-collector - Enables wired-AND bus structures, level shifting, and interfacing with higher-voltage peripherals using external pull-ups. |
| Max Output Sink Current | 24 mA per output - Supports direct driving of LEDs, relays, or multiple LS-TTL inputs without buffer stages. |
| Operating Temperature | 0°C to 70°C - Commercial-grade rating; not qualified for extended industrial or military temperature ranges. |
| Input Fan-in / Fan-out | 1 unit load input / 20 LS-TTL loads output - Defines interconnect capacity and loading limits on driving and driven stages. |
Pinout & Package
SN74LS33NG4 is supplied in a 14-pin plastic dual in-line package (PDIP), with 0.3-inch body width and through-hole mounting. The package conforms to JEDEC MS-001 and features tin/lead (NIPDAU) finish, RoHS-compliant, and MSL-unrated due to moisture-insensitive construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 5, 8, 9, 11, 12 | Input A/B of NAND gates | Four independent NAND pairs: (1&2), (4&5), (8&9), (11&12); TTL-compatible voltage thresholds and current-sinking inputs. |
| 3, 6, 10, 13 | Open-collector output | Each drives low actively; requires external pull-up to define high state; supports mixed-voltage bus termination. |
| 7 | GND | Ground reference for all logic and output stages; must be low-impedance to maintain noise margin and switching integrity. |
| 14 | VCC | +5 V supply rail; bypassing with 0.1 µF ceramic capacitor near pin is mandatory for stable high-speed operation. |
Key Features
| Feature | Design Value |
|---|---|
| Wired-AND capability | Enables shared-bus arbitration and priority encoding without additional logic gates or discrete components. |
| TTL input compatibility | Accepts standard TTL output levels (≤0.8 V low, ≥2.0 V high), eliminating need for level-shifting circuitry in mixed-logic designs. |
| High sink current (24 mA) | Drives electromechanical loads (e.g., small relays) or multiple downstream gates directly-reducing BOM count. |
| Low propagation delay (15 ns) | Supports reliable operation up to ~30 MHz clock rates in combinatorial paths with minimal timing skew. |
| Input clamp diodes | Provide ESD and transient protection on all inputs, improving robustness in noisy industrial environments. |
Applications
| Industrial Control Bus | Legacy System Interface |
|---|---|
Use Scenario: Interfacing microcontroller GPIOs to 12 V PLC input modules via shared enable lines. IC Role / Device Role / Timing Role: Level-translating wired-AND gate enabling multi-source bus arbitration with fail-safe inactive-high signaling. Use Value: Eliminates discrete transistor arrays while maintaining voltage isolation and deterministic bus contention resolution. |
Use Scenario: Adapting vintage minicomputer backplane signals to modern FPGA I/O banks operating at 3.3 V. IC Role / Device Role / Timing Role: Open-collector translator buffering TTL logic levels and converting to 3.3 V–compatible active-low handshake signals. Use Value: Preserves signal integrity and timing margins without custom level-shifters or resistor networks. |
| LED Matrix Driver | Priority Encoder Input Stage |
Use Scenario: Driving common-anode 8×8 LED matrix rows with row-select logic controlled by microcontroller. IC Role / Device Role / Timing Role: NAND-based row-enable gate sinking up to 24 mA per line to illuminate multiple LEDs simultaneously. Use Value: Delivers sufficient current per segment without external drivers, simplifying PCB layout and thermal management. |
Use Scenario: Encoding interrupt request lines from eight peripheral devices into three-bit priority-coded output. IC Role / Device Role / Timing Role: Wired-AND combinatorial logic implementing highest-priority assertion detection before feeding to encoder IC. Use Value: Reduces gate count and propagation latency versus discrete diode-OR solutions, improving interrupt response time. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NAND gate with open-collector output applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS03N | Same 74LS family, identical PDIP-14 package and open-collector NAND functionality; differs only in internal logic configuration (dual 2-input vs. quad 2-input). | Provides two gates instead of four; suitable when board space or gate count permits reduction. | Select SN74LS03N if only two open-collector NANDs are needed and footprint reuse is prioritized. |
| SN74ALS33N | Advanced Low-Power Schottky variant: lower ICC (4 mA vs. 8 mA), faster tpd (10 ns), but reduced output sink (8 mA) and stricter VCC tolerance (4.5–5.5 V). | Better suited for low-power, high-speed designs where load current demand is ≤8 mA per output. | Choose SN74ALS33N only when power efficiency and speed outweigh drive strength requirements. |
Compared with SN74LS03N and SN74ALS33N, the SN74LS33NG4 offers the optimal balance of gate density, output drive, and legacy system compatibility-making it preferred for retrofitting, industrial bus interfaces, and medium-current digital interfacing where four independent open-collector gates are required.
Availability
SN74LS33NG4 is available at Aetrix Electronics and suitable for industrial control panels, legacy system upgrades, and embedded instrumentation requiring stable component supply, long-lifecycle support, and through-hole assembly compatibility.
Supply support for SN74LS33NG4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic technologies, with over 90 years of innovation in industrial, automotive, and communications markets.
The SN74LS33NG4 belongs to TI's legacy 74LS logic product line, engineered for backward compatibility, robustness in harsh electrical environments, and ease of integration into established TTL-based architectures.
FAQ
What is the maximum recommended supply voltage for SN74LS33NG4?
The SN74LS33NG4 is rated for operation between 4.75 V and 5.25 V. Exceeding 5.25 V risks permanent damage to internal transistors and violates absolute maximum ratings specified in the official TI datasheet. For stable performance, maintain VCC within this window using regulated 5 V sources and local 0.1 µF decoupling.
Can SN74LS33NG4 drive a 12 V relay coil directly?
Yes - the SN74LS33NG4 open-collector output can sink up to 24 mA, which is sufficient for many small 12 V relays with coil resistances ≥500 Ω. An external 12 V pull-up must be used, and a flyback diode across the coil is mandatory to suppress inductive kickback that could damage the output transistor.
Is SN74LS33NG4 pin-compatible with SN74LS00N?
No - while both are 14-pin PDIP NAND gates, SN74LS00N has push-pull (totem-pole) outputs and different pin assignments: its outputs are on pins 3, 6, 8, and 11, whereas SN74LS33NG4 outputs are on pins 3, 6, 10, and 13. Substituting one for the other without circuit revision will cause functional failure.
Does SN74LS33NG4 support mixed-voltage logic interfacing?
Yes - its open-collector outputs allow connection to pull-up voltages independent of VCC, enabling interoperability with 3.3 V, 5 V, or 12 V logic families. Inputs remain TTL-compatible (0.8 V/2.0 V thresholds), so driving from 3.3 V CMOS may require series resistors or level-shifting to ensure valid low-level recognition.
What is the thermal resistance (θJA) of SN74LS33NG4 in PDIP package?
The junction-to-ambient thermal resistance for SN74LS33NG4 in PDIP-14 package is 63°C/W under standard JEDEC test conditions (single-layer board, 1 in² copper pad). This value assumes no added heatsinking; actual θJA improves with larger copper areas or forced airflow, critical when sinking >15 mA continuously per output.
SN74LS33NG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- Logic Type:
- NOR Gate
- Number of Circuits:
- 4
- Number of Inputs:
- 2
- Features:
- Open Collector
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Max):
- -
- Current - Output High, Low:
- -, 24mA
- Input Logic Level - Low:
- 0.8V
- Input Logic Level - High:
- 2V
- Max Propagation Delay @ V, Max CL:
- 32ns @ 5V, 45pF
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-PDIP
SN74LS33NG4 FAQ
1.How can I place an order for SN74LS33NG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS33NG4 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SN74LS33NG4 reliable?
The price and inventory of SN74LS33NG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS33NG4 is usually 5 days.
3.What payment methods are accepted for SN74LS33NG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS33NG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS33NG4?
SN74LS33NG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS33NG4 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SN74LS33NG4?
For technical support, including SN74LS33NG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS33NG4 requirements.
6.How does Aetrix verify that SN74LS33NG4 is sourced from the original manufacturer or authorized distributors?
All SN74LS33NG4 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74LS33NG4 meets industry standards.
7.What is the process for return or replacement of SN74LS33NG4?
All SN74LS33NG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS33NG4, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SN74LS33NG4 part is unused and in its original packaging.
Return procedure for SN74LS33NG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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