SCES577E JUNE   2004  – November 2015 SN74AVCH4T245

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics
    6. 7.6  Switching Characteristics, VCCA = 1.2 V
    7. 7.7  Switching Characteristics, VCCA = 1.5 V ± 0.1 V
    8. 7.8  Switching Characteristics, VCCA = 1.8 V ± 0.15 V
    9. 7.9  Switching Characteristics, VCCA = 2.5 V ± 0.2 V
    10. 7.10 Switching Characteristics, VCCA = 3.3 V ± 0.3 V
    11. 7.11 Operating Characteristics
    12. 7.12 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Fully Configurable Dual-Rail Design Allows Each Port to Operate Over the Full 1.2V to 3.6V Power-Supply Range
      2. 9.3.2 Supports High Speed Translation
      3. 9.3.3 Ioff Supports Partial-Power-Down Mode Operation
      4. 9.3.4 Bus-Hold Circuitry
      5. 9.3.5 Vcc Isolation Feature
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curve
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Community Resources
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9 Detailed Description

9.1 Overview

The SN74AVCH4T245 is a 4-bit, dual-supply noninverting bidirectional voltage level translation device. Ax pins and control pins (1DIR, 2DIR,1OE, and 2OE) are supported by VCCA, and Bx pins are supported by VCCB. The A port is able to accept I/O voltages ranging from 1.2 V to 3.6 V, while the B port can accept I/O voltages from 1.2 V to 3.6 V. A high on DIR allows data transmission from Ax to Bx and a low on DIR allows data transmission from Bx to Ax when OE is set to low. When OE is set to high, both Ax and Bx pins are in the high-impedance state. Refer to the AVC Logic Family Technology and Applications Application Report SCEA006).

9.2 Functional Block Diagram

SN74AVCH4T245 lo_ces576.gif Figure 4. Logic Diagram (Positive Logic) for 1/2 of SN74AVCH4T245

9.3 Feature Description

9.3.1 Fully Configurable Dual-Rail Design Allows Each Port to Operate Over the Full 1.2V to 3.6V Power-Supply Range

Both VCCA and VCCB can be supplied at any voltage between 1.2 V and 3.6 V; thus, making the device suitable for translating between any of the low voltage nodes (1.2 V, 1.8 V, 2.5 V, and 3.3 V).

9.3.2 Supports High Speed Translation

The SN74AVCH4T245 device can support high data rate applications. The translated signal data rate can be up to 380 Mbps when the signal is translated from 1.8 V to 3.3 V.

9.3.3 Ioff Supports Partial-Power-Down Mode Operation

Ioff will prevent backflow current by disabling I/O output circuits when device is in partial-power-down mode.

9.3.4 Bus-Hold Circuitry

This device has active bus-hold circuitry that holds unused or undriven inputs at a valid logic state. Use of pull-up or pull-down resistors with the bus-hold circuitry is not recommended. (Refer to the Bus-Hold Circuit Application Report (SCLA015). Pullup and pulldown resistors are not recommended on the inputs of devices with bus-hold. Unused inputs can be left floating.

9.3.5 Vcc Isolation Feature

The VCC isolation feature ensures that if either VCCA or VCCB are at GND (or < 0.4V), both ports will be in a high-impedance state (IOZ shown in Electrical Characteristics). This prevents false logic levels from being presented to either bus.

9.4 Device Functional Modes

Table 1 lists the functional modes of the SN74AVCH4T245.

Table 1. Function Table (Each 2-Bit Section)

CONTROL INPUTS(1) OUTPUT CIRCUITS OPERATION
OE DIR A PORT B PORT
L L Enabled Hi-Z B data to A bus
L H Hi-Z Enabled A data to B bus
H X Hi-Z Hi-Z Isolation
(1) Input circuits of the data I/Os are always active.