SN74LVC16T245DGGR

The SN74LVC16T245DGGR is Texas Instruments’ 16-bit dual-supply bus transceiver from the 74LVC family, designed for asynchronous communication between data buses operating at different voltage levels. The device features two independent 8-bit transceivers, each with separate direction (DIR) and output-enable (OE) control inputs referenced to VCCA. The A port tracks VCCA (1.65V to 5.5V) and the B port tracks VCCB (1.65V to 5.5V), enabling universal bidirectional translation between any combination of 1.8V, 2.5V, 3.3V, and 5V logic levels. The device supports data rates up to 200Mbps with typical propagation delay of 4.3ns. Overvoltage-tolerant I/O allows safe connection to higher-voltage buses, while the Ioff feature and VCC isolation ensure safe operation during partial power-down conditions.

Dual-Supply Level Translation

The SN74LVC16T245DGGR uses two independent power supply rails (VCCA and VCCB) to enable voltage-level translation between two different voltage domains. The A-port I/O levels are referenced to VCCA and the B-port I/O levels are referenced to VCCB. Each 8-bit transceiver can independently translate signals between the two voltage domains, controlled by DIR and OE pins supplied by VCCA.

Direction and Enable Control

Each 8-bit section has separate DIR and OE controls. When OE is low and DIR is high, data flows from A to B. When OE is low and DIR is low, data flows from B to A. When OE is high, both A and B outputs enter the high-impedance state, isolating the device from the bus. This tri-state capability enables multiple devices to share a common bus.

Overvoltage Tolerance

Both A and B port I/O pins are overvoltage-tolerant, allowing them to be connected to voltage rails higher than their respective VCC supplies without causing latch-up or damage. This is essential in mixed-voltage systems where signal lines may originate from a different voltage domain.

Power-Down Protection

The Ioff circuitry ensures that when either VCC rail is at GND, all I/O pins enter a high-impedance state, preventing damaging backflow current. The VCC isolation feature further ensures that if either supply is absent, both ports remain in high-impedance, protecting upstream and downstream circuitry.

• Mixed-voltage microcontroller and FPGA systems requiring bidirectional translation between 1.8V, 2.5V, 3.3V, and 5V domains
• SPI and UART communication interfaces between processors operating at different logic levels
• Industrial PLC and automation I/O modules needing 16-bit bus buffering with tri-state control
• Backplane and system bus transceivers where multiple voltage domains must communicate reliably
• Portable electronics with dynamic voltage scaling requiring fast 200Mbps level translation