SCPS200E July   2009  – April 2019 TCA9555

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
    1.     Pin 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 I2C Interface Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 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 5-V Tolerant I/O Ports
      2. 9.3.2 Hardware Address Pins
      3. 9.3.3 Interrupt (INT) Output
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power-On Reset (POR)
      2. 9.4.2 Powered-Up
    5. 9.5 Programming
      1. 9.5.1 I/O Port
      2. 9.5.2 I2C Interface
        1. 9.5.2.1 Bus Transactions
          1. 9.5.2.1.1 Writes
          2. 9.5.2.1.2 Reads
      3. 9.5.3 Device Address
      4. 9.5.4 Control Register and Command Byte
    6. 9.6 Register Maps
      1. 9.6.1 Register Descriptions
  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 Calculating Junction Temperature and Power Dissipation
        2. 10.2.2.2 Minimizing ICC When I/O Is Used to Control LED
        3. 10.2.2.3 Pull-Up Resistor Calculation
      3. 10.2.3 Application Curves
  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 Receiving Notification of Documentation Updates
    3. 13.3 Community Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

11 Power Supply Recommendations

In the event of a glitch (data output or input or even power) or data corruption, the TCA9555 can be reset to its default conditions by using the power-on reset feature. Power-on reset requires that the device go through a power cycle to be completely reset. This reset also happens when the device is powered on for the first time in an application.

The two types of power-on reset are shown in Figure 39 and Figure 40.

TCA9555 pwron01_cps200.gifFigure 39. VCC is Lowered Below 0.2 V or 0 V and Then Ramped Up to VCC
TCA9555 pwron02_cps200.gifFigure 40. VCC is Lowered Below the POR Threshold, Then Ramped Back Up to VCC

Table 9 specifies the performance of the power-on reset feature for TCA9555 for both types of power-on reset.

Table 9. RECOMMENDED SUPPLY SEQUENCING AND RAMP RATES(1)

PARAMETER MIN TYP MAX UNIT
VCC_FT Fall rate of VCC See Figure 39 0.1 2000 ms
VCC_RT Rise rate of VCC See Figure 39 0.1 2000 ms
VCC_TRR_GND Time to re-ramp (when VCC drops to GND) See Figure 39 1 μs
VCC_TRR_POR50 Time to re-ramp (when VCC drops to VPOR_MIN – 50 mV) See Figure 40 1 μs
VCC_GH Level that VCCP can glitch down to, but not cause a functional disruption when VCC_GW See Figure 41 1.2 V
VCC_MV The minimum voltage that VCC can glitch down to without causing a reset (VCC_GH must also not be violated) See Figure 41 1.5 V
VCC_GW Glitch width that does not cause a functional disruption See Figure 41 10 μs
(1) TA = –40°C to +85°C (unless otherwise noted)

Glitches in the power supply can also affect the power-on reset performance of this device. The glitch width (VCC_GW) and height (VCC_GH) are dependent on each other. The bypass capacitance, source impedance, and device impedance are factors that affect power-on reset performance. Figure 41 and Table 9 provide more information on how to measure these specifications.

TCA9555 pwron03_scps254.gifFigure 41. Glitch Width and Glitch Height

VPOR is critical to the power-on reset. VPOR is the voltage level at which the reset condition is released and all the registers and the I2C/SMBus state machine are initialized to their default states. The value of VPOR differs based on the VCC being lowered to or from 0. Figure 42 and Table 9 provide more details on this specification.

TCA9555 pwron04_cps200.gifFigure 42. VPOR