Overview
The SN74AC373NG4 is an octal D-type transparent latch produced by Texas Instruments. This component is part of the 74AC family, known for its high-speed and low-power CMOS logic. The device features eight D-type latches with 3-state outputs, making it suitable for a variety of applications including buffer registers, I/O ports, bidirectional bus drivers, and working registers.
When the latch-enable (LE) input is high, the Q outputs follow the data (D) inputs. When LE is taken low, the Q outputs are latched at the logic levels set up at the D inputs. A buffered output-enable (OE) input allows the outputs to be placed in either a normal logic state or a high-impedance state, enabling direct drive of bus lines.
Key Specifications
| Parameter | Unit | Min | Typ | Max |
|---|---|---|---|---|
| VCC Supply Voltage | V | 2 | 6 | |
| VIH High-Level Input Voltage (VCC = 5.5V) | V | 3.85 | ||
| VIL Low-Level Input Voltage (VCC = 5.5V) | V | 1.65 | ||
| IOH High-Level Output Current (VCC = 5.5V) | mA | -24 | ||
| IOL Low-Level Output Current (VCC = 5.5V) | mA | 24 | ||
| TA Operating Free-Air Temperature | °C | -40 | 85 | |
| tPLH Propagation Delay Time (VCC = 5V) | ns | 1.5 | 7 | 9.5 |
| tPHL Propagation Delay Time (VCC = 5V) | ns | 1.5 | 7 | 9.5 |
| tw Pulse Duration, LE High (VCC = 5V) | ns | 4 | 5 | |
| tsu Setup Time, Data Before LE↓ (VCC = 5V) | ns | 4 | 5 | |
| th Hold Time, Data After LE↓ (VCC = 5V) | ns | 1 |
Key Features
- Operation over a wide VCC range of 2V to 6V.
- Inputs accept voltages up to 6V.
- Maximum propagation delay time of 9.5ns at VCC = 5V.
- 3-state noninverting outputs capable of driving bus lines directly.
- Full parallel access for loading data.
- Buffered output-enable input for high-impedance state control.
- Suitable for implementing buffer registers, I/O ports, bidirectional bus drivers, and working registers.
Applications
- Buffer registers: To temporarily store data and protect it from changes.
- I/O ports: For controlling and managing input/output operations in digital systems.
- Bidirectional bus drivers: To manage data flow in both directions on a bus line.
- Working registers: For temporary storage and manipulation of data within a system.
- General-purpose logic circuits: Where high-speed and low-power logic operations are required.
Q & A
- What is the operating voltage range of the SN74AC373NG4?
The SN74AC373NG4 operates over a VCC range of 2V to 6V.
- What is the maximum propagation delay time at VCC = 5V?
The maximum propagation delay time at VCC = 5V is 9.5ns.
- What is the purpose of the output-enable (OE) input?
The output-enable (OE) input allows the outputs to be placed in either a normal logic state or a high-impedance state.
- What are the typical applications of the SN74AC373NG4?
The SN74AC373NG4 is typically used in buffer registers, I/O ports, bidirectional bus drivers, and working registers.
- What is the significance of the latch-enable (LE) input?
The latch-enable (LE) input controls whether the Q outputs follow the D inputs or are latched at the current logic levels.
- What are the package options available for the SN74AC373NG4?
The SN74AC373NG4 is available in various packages including SSOP, SOIC, PDIP, SOP, and TSSOP.
- What is the maximum continuous output current per output?
The maximum continuous output current per output is ±50 mA.
- What is the recommended operating temperature range?
The recommended operating temperature range is -40°C to 85°C.
- How should unused inputs be handled for proper device operation?
Unused inputs must be held at VCC or GND for proper device operation.
- What is the significance of the 3-state outputs?
The 3-state outputs are designed to drive highly capacitive or relatively low-impedance loads directly and can be placed in a high-impedance state.
