SN74AXC4T245 - 4-Bit Dual-Supply Bus Transceiver

The SN74AXC4T245 is a four-bit noninverting bus transceiver that uses two individuallyconfigurable power-supply rails. The device is operational with both V_CCAand V_CCB supplies as low as 0.65 V. The A port is designed to trackV_CCA, which accepts any supply voltage from 0.65 V to 3.6 V. The B port isdesigned to track V_CCB, which also accepts any supply voltage from 0.65 V to3.6 V. Additionally the SN74AXC4T245 is compatible with a single-supply system.

The SN74AXC4T245 device is designed for asynchronous communication between data buses.The device transmits data from the A bus to the B bus or from the B bus to the A bus, depending onthe logic level of the direction-control inputs (1DIR and 2DIR). The output-enable inputs(1OE and 2OE) are used to disable the outputs so thebuses are effectively isolated. The SN74AXC4T245 device is designed so the control pins (xDIR andxOE) are referenced to V_CCA.

To ensure the high-impedance state of the level shifter I/Os during power up or powerdown, the xOE pins should be tied to V_CCA through apullup resistor.

This device is fully specified for partial-power-down applications using theI_off current. The I_off protection circuitry ensuresthat no excessive current is drawn from or to an input, output, or combined I/O that is biased to aspecific voltage while the device is powered down.

The V_CC isolation feature ensures that if eitherV_CCA or V_CCB is less than 100 mV, both I/O portsenter a high-impedance state by disabling their outputs.

Glitch-Free power supply sequencing allows either supply rail to be powered on or off inany order while providing robust power sequencing performance.

• Fully Configurable Dual-Rail Design Allows Each Port to Operate With a Power Supply Range From 0.65 V to 3.6 V
• Operating Temperature From –40°C to +125°C
• Multiple Direction Control Pins to Allow Simultaneous Up and Down Translation
• Glitch-Free Power Supply Sequencing
• Up to 380 Mbps Support When Translating from 1.8 V to 3.3 V
• V_CC Isolation Feature
  • If Either V_CC Input is Below 100 mV, All I/Os Outputs are Disabled and Become High-Impedance
• I_off Supports Partial-Power-Down Mode Operation
• Compatible With AVC Family Level Shifters
• Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
• ESD Protection Exceeds JESD 22
  • 8000-V Human-Body Model
  • 1000-V Charged-Device Model

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