Overview
The SN74HC20NS, produced by Texas Instruments, is a dual 4-input NAND gate integrated circuit. This device is part of the HC (High-Speed CMOS) logic family and is designed to operate over a wide range of voltages and temperatures. It contains two independent 4-input NAND gates, each performing the Boolean function Y = A ● B ● C ● D in positive logic.
The SN74HC20NS is available in a 14-pin Small Outline Package (SOP), making it suitable for various digital logic applications where compact size and high performance are required.
Key Specifications
| Parameter | Min | Max | Unit | |
|---|---|---|---|---|
| VCC (Supply Voltage) | 2 | 5 | 6 | V |
| VIH (High-level Input Voltage) | 1.5 (VCC=2V) | 3.15 (VCC=4.5V) | 4.2 (VCC=6V) | V |
| VIL (Low-level Input Voltage) | 0.5 (VCC=2V) | 1.35 (VCC=4.5V) | 1.8 (VCC=6V) | V |
| TA (Operating Free-Air Temperature) | -40 | 85 | °C | |
| VOH (High-level Output Voltage) | 1.9 (VCC=2V, IOH=-20µA) | V | ||
| VOL (Low-level Output Voltage) | 0.17 (VCC=4.5V, IOL=4mA) | V | ||
| tpd (Propagation Delay) | 9 (VCC=4.5V, CL=50pF) | 28 (VCC=4.5V, CL=50pF) | ns | |
| tt (Transition Time) | 9 (VCC=4.5V, CL=50pF) | 19 (VCC=4.5V, CL=50pF) | ns |
Key Features
- Buffered inputs
- Wide operating voltage range: 2 V to 6 V
- Wide operating temperature range: -40°C to +85°C
- Supports fanout up to 10 LSTTL loads
- Significant power reduction compared to LSTTL logic ICs
- Balanced CMOS push-pull outputs
- Capable of driving larger currents than the device can sustain without damage, with proper output power limitation
Applications
- Alarm / tamper detect circuits
- S-R latch circuits
- General digital logic circuits requiring 4-input NAND gates
Q & A
- What is the function of the SN74HC20NS?
The SN74HC20NS contains two independent 4-input NAND gates, each performing the Boolean function Y = A ● B ● C ● D in positive logic.
- What is the operating voltage range of the SN74HC20NS?
The operating voltage range is from 2 V to 6 V.
- What is the operating temperature range of the SN74HC20NS?
The operating temperature range is from -40°C to +85°C.
- What type of package is the SN74HC20NS available in?
The SN74HC20NS is available in a 14-pin Small Outline Package (SOP).
- What are the key features of the SN74HC20NS?
Key features include buffered inputs, wide operating voltage and temperature ranges, support for up to 10 LSTTL loads, and significant power reduction compared to LSTTL logic ICs.
- How many NAND gates does the SN74HC20NS contain?
The SN74HC20NS contains two independent 4-input NAND gates.
- What are some common applications of the SN74HC20NS?
Common applications include alarm / tamper detect circuits, S-R latch circuits, and general digital logic circuits requiring 4-input NAND gates.
- What is the propagation delay of the SN74HC20NS?
The propagation delay is typically 9 ns to 28 ns at VCC = 4.5 V and CL = 50 pF.
- How should unused inputs be handled on the SN74HC20NS?
Unused inputs should be tied to either VCC or GND, whichever is more convenient for the logic function or application.
- What are the thermal considerations for the SN74HC20NS?
The device has specified thermal metrics such as junction-to-ambient thermal resistance, and proper layout and design practices should be followed to ensure thermal dissipation and prevent overheating.
