SCDS001O November   1992  – September 2015 SN74CBT3244

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Package
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    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 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DGV|20
  • DB|20
  • DBQ|20
  • DW|20
  • PW|20
  • RGY|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8 Detailed Description

8.1 Overview

The SN74CBT3244 has eight bits of high-speed TTL-compatible bus switching. The switches are grouped in the 2 groups of 4 bits each. Each group has output-enabled inputs to allow signals to pass between A and B ports. The signals can travel from A port to B port or vice versa.

The low ON-state resistance of the switch allows connections to be made with minimal propagation delay. The device is ideal for switching high speed digital signals between microprocessors and peripheral devices which is useful in test applications, measurement applications, and control boards for factory automation.

8.2 Functional Block Diagram

SN74CBT3244 logic_diag_scds001.gif Figure 3. Simplified Schematic

8.3 Feature Description

The SN74CBT3244 device support same pin configuration as industry standard '244. This device has a near zero propagation delay allowing high speed signal switching up to 200 Mhz. The signals see lower distortion since the device has low ON-resistance (5 Ω) coupled with low-output capacitance (6 pF) . SN74CBT3244 has a very low power consumption in idle state consuming ICC of 50 µA only allowing power-saving for the system. The device supports signal inputs any where between 0 V to 5 V.

8.4 Device Functional Modes

The device is organized as two 4-bit low-impedance switches with separate output-enable (OE) inputs.The Output Enable OE is active low, implying when low A port is connected to B port. This switch is bidirectional in nature. Asserting OE high will disconnect A port from B port. To ensure the high-impedance state during power up or power down, OE should be tied to VCC through a pullup resistor. The minimum value of the resistor is determined by the current-sinking capability of the driver.

Table 1. Function Table
(Each 4-Bit Bus Switch)

INPUT OE FUNCTION
L A port = B port
H Disconnect