SLRS023E December   1976  – January 2015 SN75468 , SN75469

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Simplified Schematic
  5. 5 Revision History
  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
    7. 7.7 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
    4. 9.4 Device Functional Modes
      1. 9.4.1 Inductive Load Drive
      2. 9.4.2 Resistive Load Drive
  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
        1. 10.2.2.1 Drive Current
        2. 10.2.2.2 Output Low Voltage
        3. 10.2.2.3 Power Dissipation & Temperature
      3. 10.2.3 Application Curves
    3. 10.3 System Examples
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Related Links
    2. 13.2 Trademarks
    3. 13.3 Electrostatic Discharge Caution
    4. 13.4 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • NS|16
  • N|16
  • D|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

10 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

10.1 Application Information

SN75468 will typically be used to drive a high voltage and/or current peripheral from an MCU or logic device that cannot tolerate these conditions. The following design is a common application of SN75468, driving inductive loads. This includes motors, solenoids & relays. Each load type can be modeled by what's seen in Figure 16.

10.2 Typical Application

relay_drv.gifFigure 16. SN75468 as Inductive Load Driver

10.2.1 Design Requirements

For this design example, use the parameters listed in Table 1 as the input parameters.

Table 1. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE
GPIO Voltage 3.3 V or 5.0 V
Coil Supply Voltage 12 V to 100 V
Number of Channels 7
Output Current (RCOIL) 20 mA to 300 mA per channel
Duty Cycle 100%

10.2.2 Detailed Design Procedure

When using SN75468 in a coil driving application, determine the following:

  • Input voltage range
  • Temperature range
  • Output and drive current
  • Power dissipation

10.2.2.1 Drive Current

The coil current is determined by the coil voltage (VSUP), coil resistance & output low voltage (VOL or VCE(SAT)).

Equation 1. ICOIL = (VSUP – VCE(SAT)) / RCOIL

10.2.2.2 Output Low Voltage

The output low voltage (VOL) is the same thing as VCE(SAT) and can be determined by the Electrical Characteristics table, Figure 1, or Figure 2.

10.2.2.3 Power Dissipation & Temperature

The number of coils driven is dependent on the coil current and on-chip power dissipation. The number of coils driven can be determined by Figure 4 or Figure 5.

For a more accurate determination of number of coils possible, use the below equation to calculate SN75468 on-chip power dissipation PD:

Equation 2. eq1_lrs059.gif
Where:
N is the number of channels active together.
VOLi is the OUTi pin voltage for the load current ILi. This is the same as VCE(SAT)

In order to guarantee reliability of SN75468 and the system the on-chip power dissipation must be lower that or equal to the maximum allowable power dissipation (PD(MAX)) dictated by below equation Equation 3.

Equation 3. eq2_lrs059.gif
Where:
TJ(MAX) is the target maximum junction temperature.
TA is the operating ambient temperature.
θJA is the package junction to ambient thermal resistance.

It is recommended to limit SN75468 IC’s die junction temperature to less than 125°C. The IC junction temperature is directly proportional to the on-chip power dissipation.

10.2.3 Application Curves

The following curves were generated with SN75468 driving an OMRON G5NB relay – Vin = 5.0V; Vsup= 12 V & RCOIL= 2.8 kΩ

D010_ULN2003B.gifFigure 17. Output Response With Activation of Coil (Turn On)
D009_ULN2003B.gifFigure 18. Output Response With De-activation of Coil (Turn Off)

10.3 System Examples

typ_app1_slrs023.gifFigure 19. TTL to Load Schematic
typ_app2_slrs023.gifFigure 20. Buffer to Higher Current Loads Schematic
typ_app3_slrs023.gifFigure 21. Pull-up Resistor Schematic