SN74AVCH8T245 - 8-Bit Dual-Supply Bus Transceiver with Configurable Voltage Translation and 3-State Outputs

The SN74AVCH8T245 is an 8-bit noninverting bus transceiver that uses two separate configurable power-supply rails. The A port is designed to track V_CCA, which accepts any supply voltage from 1.2 V to 3.6 V. The B port is designed to track V_CCB, which also accepts any supply voltage from 1.2 V to 3.6 V. This allows for universal low-voltage bidirectional translation between any of the 1.2-V, 1.5-V, 1.8-V, 2.5-V, and 3.3-V voltage nodes.

The SN74AVCH8T245 is designed for asynchronous communication between data buses. The device transmits data from either the A bus to the B bus, or from the B bus to the A bus, depending on the logic level at the direction-control (DIR) input. The output-enable (OE) input can be used to disable the outputs so the buses are effectively isolated.

The SN74AVCH8T245 is designed so that the control pins (DIR and OE) are referenced to V_CCA.

Active bus-hold circuitry holds unused or undriven inputs at a valid logic state. Use of pullup or pulldown resistors with the bus-hold circuitry is not recommended.

This device is fully specified for partial-power-down applications using I_off. The I_off circuitry disables the outputs, preventing damaging current backflow through the device.

The V_CC isolation feature ensures that if either V_CCA or V_CCB is at GND, then the outputs are in the high-impedance state. The bus-hold circuitry on the powered-up side always stays active.

The SN74AVCH8T245 solution is compatible with a single-supply system and can be replaced later with a ’245 function, with minimal printed circuit board redesign.

To ensure the high-impedance state during power up or power down, OE shall be tied to V_CCA through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

• Control Inputs (DIR and OE) V_IH and V_IL Levels Are Referenced to V_CCA Voltage
• Bus Hold on Data Inputs Eliminates the Need for External Pullup or Pulldown Resistors
• V_CC Isolation Feature
• Fully Configurable Dual-Rail Design
• I/Os Are 4.6-V Tolerant
• I_off Supports Partial-Power-Down Mode Operation
• Max Data Rates:
  • 320 Mbps (V_CCA ≥ 1.8 V and V_CCB ≥ 1.8 V)
  • 170 Mbps (V_CCA ≤ 1.8 V or V_CCB ≤ 1.8 V)
• Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
• ESD Protection Exceeds JESD 22
  • 8000-V Human-Body Model (A114-A)
  • 200-V Machine Model (A115-A)
  • 1000-V Charged-Device Model (C101)