Overview
The SN74HCS21PWR is a dual 4-input AND gate integrated circuit produced by Texas Instruments. This device features Schmitt-trigger inputs and is designed to operate within a wide voltage range of 2 V to 6 V. It is available in a 14-pin TSSOP (Thin Shrink Small Outline Package) and SOIC (Small Outline Integrated Circuit) packages. The SN74HCS21PWR is part of the HCS (High-Speed CMOS) logic family, known for its high-speed operation and low power consumption.
Key Specifications
| Parameter | Min | Max | Unit | |
|---|---|---|---|---|
| VCC Supply Voltage | -0.5 | 7 | V | |
| Input Clamp Current (IIK) | ±20 mA | |||
| Output Clamp Current (IOK) | ±20 mA | |||
| Continuous Output Current (IO) | ±35 mA | |||
| Continuous Current through VCC or GND | ±70 mA | |||
| Junction Temperature (TJ) | 150 °C | |||
| Storage Temperature (Tstg) | -65 °C | 150 °C | ||
| Positive Switching Threshold (VT+) | 0.7 V (at 2 V VCC) | 1.5 V (at 2 V VCC) | 3.15 V (at 2 V VCC) | V |
| Negative Switching Threshold (VT-) | 0.3 V (at 2 V VCC) | 1.0 V (at 2 V VCC) | 2.2 V (at 2 V VCC) | V |
| Hysteresis (ΔVT) | 0.2 V (at 2 V VCC) | 1.0 V (at 2 V VCC) | 1.4 V (at 2 V VCC) | V |
| High-Level Output Voltage (VOH) | VCC - 0.1 V (at IOH = -20 µA) | V |
Key Features
- Schmitt-Trigger Inputs: Provides noise immunity and hysteresis, allowing the inputs to be held at any valid value without significant increases in power consumption.
- Dual 4-Input AND Gates: Each gate performs the Boolean function Y = A ● B ● C ● D in positive logic.
- Wide Operating Voltage Range: Operates from 2 V to 6 V, making it versatile for various applications.
- High-Speed Operation: Propagation delay as low as 12 ns.
- CMOS Technology: Balanced CMOS push-pull outputs for fast edges and low power consumption.
- Extended Ambient Temperature Range: Operates from -40°C to +125°C.
- Low Power Consumption: Supply current as low as 0.1 µA at 6 V VCC.
Applications
- Combining Power Good Signals: Can be used to combine multiple power good signals to ensure all power rails are within specified limits before enabling system operation.
- Enable Digital Signals: Useful in applications where multiple digital signals need to be ANDed together to enable or disable a function.
- System Reset Control: Can be used to drive the RESET pin of a system controller, ensuring the controller only operates when all inputs are in a valid state.
- Noise Immune Logic Circuits: The Schmitt-trigger inputs make it suitable for applications where noise rejection is critical.
Q & A
- What is the operating voltage range of the SN74HCS21PWR?
The SN74HCS21PWR operates from 2 V to 6 V.
- What type of inputs does the SN74HCS21PWR have?
The SN74HCS21PWR has Schmitt-trigger inputs.
- How many AND gates are in the SN74HCS21PWR, and how many inputs do they have?
The SN74HCS21PWR contains two independent 4-input AND gates.
- What is the propagation delay of the SN74HCS21PWR?
The propagation delay is as low as 12 ns.
- What are the benefits of Schmitt-trigger inputs in the SN74HCS21PWR?
Schmitt-trigger inputs provide noise immunity and hysteresis, allowing the inputs to be held at any valid value without significant increases in power consumption.
- What is the maximum junction temperature for the SN74HCS21PWR?
The maximum junction temperature is 150 °C.
- How should unused inputs be handled in the SN74HCS21PWR?
Unused inputs must be terminated to either VCC or ground, either directly or with a pull-up or pull-down resistor.
- What are the package options for the SN74HCS21PWR?
The SN74HCS21PWR is available in TSSOP (14-pin) and SOIC (14-pin) packages.
- What is the recommended capacitive load for the outputs of the SN74HCS21PWR?
The recommended capacitive load is less than or equal to 50 pF, though loads up to 70 pF can be applied but are not recommended.
- How should the power supply be configured for the SN74HCS21PWR?
Each VCC terminal should have a good bypass capacitor, such as a 0.1-μF capacitor, to prevent power disturbances.
