SCES878 March   2019 SN74AXCH4T245

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Functional Block Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics
    6. 6.6  Switching Characteristics, VCCA = 0.7 ± 0.05 V
    7. 6.7  Switching Characteristics, VCCA = 0.8 ± 0.04 V
    8. 6.8  Switching Characteristics, VCCA = 0.9 ± 0.045 V
    9. 6.9  Switching Characteristics, VCCA = 1.2 ± 0.1 V
    10. 6.10 Switching Characteristics, VCCA = 1.5 ± 0.1 V
    11. 6.11 Switching Characteristics, VCCA = 1.8 ± 0.15 V
    12. 6.12 Switching Characteristics, VCCA = 2.5 ± 0.2 V
    13. 6.13 Switching Characteristics, VCCA = 3.3 ± 0.3 V
    14. 6.14 Operating Characteristics: TA = 25°C
    15. 6.15 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Load Circuit and Voltage Waveforms
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Standard CMOS Inputs
      2. 8.3.2  Balanced High-Drive CMOS Push-Pull Outputs
      3. 8.3.3  Partial Power Down (Ioff)
      4. 8.3.4  VCC Isolation
      5. 8.3.5  Over-voltage Tolerant Inputs
      6. 8.3.6  Glitch-free Power Supply Sequencing
      7. 8.3.7  Negative Clamping Diodes
      8. 8.3.8  Fully Configurable Dual-Rail Design
      9. 8.3.9  Supports High-Speed Translation
      10. 8.3.10 Bus-Hold Data Inputs
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

3 Description

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.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
SN74AXCH4T245PW TSSOP (16) 5.00 mm x 4.40 mm
SN74AXCH4T245RSV UQFN (16) 2.60 mm x 1.80 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Functional Block Diagram

SN74AXCH4T245 FBD_AXCH4T.gif