Overview
The SN74HC125DBR, produced by Texas Instruments, is a quadruple buffer with 3-state outputs. This device is part of the 74HC series, known for its high-speed CMOS logic. It contains four independent buffers, each performing the Boolean function Y = A in positive logic. The device is designed to operate over a wide voltage range and temperature, making it versatile for various applications.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Supply Voltage | 2 | 5 | 6 | V |
| Operating Temperature Range | -40 | - | 85 | °C |
| High-Level Input Voltage (VIH) | 1.5 (VCC=2V) | 3.15 (VCC=4.5V) | 4.2 (VCC=6V) | V |
| Low-Level Input Voltage (VIL) | 0.5 (VCC=2V) | 1.35 (VCC=4.5V) | 1.8 (VCC=6V) | V |
| Output High Voltage (VOH) | 1.9 (IOH=-20µA, VCC=2V) | 4.4 (IOH=-20µA, VCC=4.5V) | 5.9 (IOH=-20µA, VCC=6V) | V |
| Output Low Voltage (VOL) | 0.1 (IOL=20mA, VCC=2V) | 0.1 (IOL=20mA, VCC=4.5V) | 0.1 (IOL=20mA, VCC=6V) | V |
| Propagation Delay (tpd) | 11 | - | - | ns |
| Input Transition Time (tt) | 1000 (VCC=2V) | 500 (VCC=4.5V) | 400 (VCC=6V) | ns |
| Input Capacitance (Ci) | 3 | - | 10 | pF |
Key Features
- Buffered inputs
- Wide operating voltage range: 2 V to 6 V
- Wide operating temperature range: –40°C to +85°C
- 3-state outputs with high-impedance state during power-up or power-down
- Significant power reduction compared to LSTTL logic ICs
- Supports fanout up to 10 LSTTL loads
- Balanced CMOS 3-state outputs capable of sinking and sourcing similar currents
- Low input current of 1 µA maximum
- Output drive capability of ±6 mA at 5 V
Applications
- TV Set-Top Boxes and DVRs
- E-meters
- Smart Grids: Transmission Line Monitoring
- Printers and Computer Peripherals
- Building Security: Control Panels
- IP Phones
- Test and Measurement: Range Readers
Q & A
- What is the operating voltage range of the SN74HC125DBR?
The operating voltage range is from 2 V to 6 V.
- What is the operating temperature range of the SN74HC125DBR?
The operating temperature range is from –40°C to +85°C.
- How many independent buffers does the SN74HC125DBR contain?
The device contains four independent buffers.
- What is the propagation delay of the SN74HC125DBR?
The typical propagation delay is around 11 ns.
- What is the input transition time for the SN74HC125DBR?
The input transition time varies from 1000 ns at 2 V to 400 ns at 6 V.
- What is the maximum output drive current of the SN74HC125DBR?
The output drive capability is ±6 mA at 5 V.
- How should unused channels of the SN74HC125DBR be handled?
Unused channels should have their inputs terminated at ground or VCC, and the output left unconnected.
- What is the purpose of the 3-state output in the SN74HC125DBR?
The 3-state output allows the device to be in a high-impedance state during power-up or power-down, enabling or disabling data connections as needed.
- What are some common applications of the SN74HC125DBR?
Common applications include TV Set-Top Boxes, E-meters, Smart Grids, Printers, Computer Peripherals, Building Security Control Panels, IP Phones, and Test and Measurement devices.
- How should the output of the SN74HC125DBR be protected from over-current?
The output power of the device should be limited to avoid damage due to over-current, following the electrical and thermal limits defined in the Absolute Maximum Ratings.
