Overview
The SN74LVC4245A, produced by Texas Instruments, is an 8-bit (octal) noninverting bus transceiver designed for bidirectional voltage translation between 3.3-V and 5-V environments. This device features two separate supply rails: the B port operates at 3.3 V (VCCB), and the A port operates at 5 V (VCCA). It is ideal for asynchronous communication between data buses and allows data transmission from the A bus to the B bus or vice versa, controlled by the direction-control (DIR) input. The output-enable (OE) input can isolate the buses when necessary.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCCA Supply Voltage Range | -0.5 | - | 6.5 | V |
| VCCB Supply Voltage Range | 2.7 | - | 3.6 | V |
| Input Voltage Range (A port) | -0.5 | - | VCCA + 0.5 | V |
| Output Voltage Range (A port) | -0.5 | - | VCCA + 0.5 | V |
| Continuous Output Current | - | - | ±50 | mA |
| Operating Temperature Range | -40 | - | 85 | °C |
| Storage Temperature Range | -65 | - | 150 | °C |
| Propagation Delay Time (Low to High Transition) | - | ~7 | - | ns |
Key Features
- Bidirectional Voltage Translator: Translates between 3.3-V and 5-V environments.
- Dual Supply Rails: B port operates at 3.3 V (VCCB), and A port operates at 5 V (VCCA).
- Control Inputs: VIH/VIL levels are referenced to VCCA voltage.
- Latch-up Performance: Exceeds 250 mA per JESD 17.
- ESD Protection: Exceeds JESD 22, 2000-V Human-Body Model, and 1000-V Charged-Device Model.
- 24 mA Drive at 3-V Supply: Suitable for heavier loads and longer traces).
Applications
The SN74LVC4245A is designed for use in various applications requiring voltage translation between 3.3-V and 5-V systems. This includes but is not limited to:
- Asynchronous Communication: Between data buses operating at different voltage levels).
- Mixed Voltage Systems: Where both 3.3-V and 5-V components need to communicate).
- Legacy System Integration: Integrating older 5-V systems with newer 3.3-V components).
Q & A
- What is the primary function of the SN74LVC4245A?
The primary function is to act as a bidirectional voltage translator between 3.3-V and 5-V environments).
- What are the supply voltage ranges for the A and B ports?
The A port operates at 4.5 V to 5.5 V (VCCA), and the B port operates at 2.7 V to 3.6 V (VCCB)).
- How does the direction-control (DIR) input work?
The DIR input controls the direction of data transmission between the A and B buses. When DIR is low, data is transmitted from the B bus to the A bus, and when DIR is high, data is transmitted from the A bus to the B bus).
- What is the purpose of the output-enable (OE) input?
The OE input can be used to disable the device, effectively isolating the buses when set high).
- What are the operating and storage temperature ranges for the SN74LVC4245A?
The operating temperature range is -40°C to 85°C, and the storage temperature range is -65°C to 150°C).
- Does the SN74LVC4245A have ESD protection?
Yes, it exceeds JESD 22 standards with 2000-V Human-Body Model and 1000-V Charged-Device Model protection).
- What is the maximum continuous output current for the SN74LVC4245A?
The maximum continuous output current is ±50 mA).
- Can the SN74LVC4245A be used in mixed voltage systems?
Yes, it is designed for use in mixed voltage systems where both 3.3-V and 5-V components need to communicate).
- What are the typical propagation delay times for the SN74LVC4245A?
The typical propagation delay time is around 7 ns for low to high transition).
- What packages are available for the SN74LVC4245A?
The device is available in SSOP (DB), SOIC (DW), and TSSOP (PW) packages).
