SCES881 February   2020 SN74AXCH2T45

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Logic Diagram (Positive Logic)
  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 ± 0.045 V
    8. 6.8  Switching Characteristics, VCCA = 0.9 ± 0.04 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
  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
    4. 8.4 Bus-Hold Data Inputs
    5. 8.5 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Enable Times
    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 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

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3 Description

The SN74AXCH2T45 is a two-bit non-inverting 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 also accepts any supply voltage from 0.65 V to 3.6 V. Additionally the SN74AXCH2T45 is compatible with a single-supply system.

The SN74AXCH2T45 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 on the logic level of the direction-control input (DIR). The SN74AXCH2T45 device is designed so the control pin (DIR) is 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 pin.

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 to 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, both I/O ports enter a high-impedance state by disabling their 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)
SN74AXCH2T45DCU VSSOP (8) 2.30 mm × 2.00 mm
SN74AXCH2T45DTM X2SON (8) 1.35 mm x 0.80 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Logic Diagram (Positive Logic)

SN74AXCH2T45 FBD_AXCH2T45.gif