The SN74AXCH4T245 is a four-bit noninverting bus transceiver that uses two individually configurable power-supply rails. The device is operational with both VCCA and VCCB supplies as low as 0.65 V. The A port is designed to track VCCA, which accepts any supply voltage from 0.65 V to 3.6 V. The B port is designed to track VCCB, which accepts any supply voltage from 0.65 V to 3.6 V. The SN74AXCH4T245 device is compatible with a single-supply system.
The SN74AXCH4T245 device is designed for asynchronous communication between data buses and transmits data from the A bus to the B bus or from the B bus to the A bus, depending on the logic level of the direction-control inputs (1DIR and 2DIR). The output-enable inputs (1OE and 2OE) are used to disable the outputs so the buses are effectively isolated. All control pins (xDIR and xOE) are referenced to VCCA.
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. If a supply is present for VCCA or VCCB, the bus-hold circuitry always remains active on the A or B inputs respectively, independent of the state of the direction control or output enable pins.
To ensure the high-impedance state of the level shifter I/Os during power up or power down, the xOE pins should be tied to VCCA through a pullup resistor.
This device is fully specified for partial-power-down applications using the Ioff current. The Ioff protection circuitry ensures that no excessive current is drawn from or sourced into an input, output, or combined I/O that is biased to a specific voltage while the device is powered down.
The VCC isolation feature ensures that if either VCCA or VCCB is less than 100 mV, all I/O ports enter a high-impedance state by disabling the outputs.
Glitch-free power supply sequencing allows either supply rail to be powered on or off in any order while providing robust power sequencing performance.
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|Part number||Order||Technology Family||Application||Bits (#)||High input voltage (Min) (Vih)||High input voltage (Max) (Vih)||Output voltage (Min) (V)||Output voltage (Max) (V)||IOH (Max) (mA)||IOL (Max) (mA)||Package Group||Rating|
TSSOP | 16
UQFN | 16
TSSOP | 48
TVSOP | 48
DSBGA | 6
SC70 | 6
SOT-23 | 6
TSSOP | 56
TVSOP | 56
DSBGA | 8
SM8 | 8
VSSOP | 8
SOIC | 16
TSSOP | 16
TVSOP | 16
UQFN | 16
VQFN | 16