SBOS550C February   2011  – May 2026 TXS4555

PRODUCTION DATA  

  1.   1
  2. 1Features
  3. 2Description
  4. 3Pin Configuration and Functions
  5. 4Specifications
    1. 4.1  Absolute Maximum Ratings
    2. 4.2  ESD Ratings
    3. 4.3  Thermal Information
    4. 4.4  Recommended Operating Conditions
    5. 4.5  Electrical Characteristics – Level Translator
    6. 4.6  LDO Electrical Characteristics
    7. 4.7  General Electrical Characteristics
    8. 4.8  Switching Characteristics
    9. 4.9  Operating Characteristics
    10. 4.10 Typical Characteristics
  6. 5Detailed Description
    1. 5.1 Functional Block Diagram
  7. 6Application and Implementation
    1. 6.1 Application Information
      1. 6.1.1 Input And Output Capacitor Requirements
      2. 6.1.2 Output Noise
      3. 6.1.3 Internal Current Limit
      4. 6.1.4 Dropout Voltage
      5. 6.1.5 Startup
      6. 6.1.6 Transient Response
      7. 6.1.7 Minimum Load
      8. 6.1.8 Thermal Information
        1. 6.1.8.1 Thermal Protection
  8. 7Device and Documentation Support
    1. 7.1 Receiving Notification of Documentation Updates
    2. 7.2 Support Resources
    3. 7.3 Trademarks
    4. 7.4 Electrostatic Discharge Caution
    5. 7.5 Glossary
  9. 8Revision History
  10. 9Mechanical, Packaging, and Orderable Information

4.7 General Electrical Characteristics

over operating free-air temperature range (unless otherwise noted)
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
RI/OPUI/O pull-up162024kΩ
RSIMPUSIM_I/O pull-up101418kΩ
RSIMPDSIM_I/O pull-downActive pull-downs are connected to the VSIM regulator output to the SIM_CLK, SIM_RST, SIM_I/O when EN = 03kΩ
TXS4555 Shutdown Sequence for SIM_RST, SIM_CLK, SIM_IO and VSIM Figure 4-1 Shutdown Sequence for SIM_RST, SIM_CLK, SIM_IO and VSIM

The shutdown sequence for the SIM signals is based on the ISO 7816-3 specification. The shutdown sequence of these signals helps to properly disable these channels and not have any corruption of data accidently. Also, this is also helpful when the SIM card is present in a hot swap slot and when pulling out the SIM card, the orderly shutdown of these signals help avoid any improper write or corruption of data.

When EN is lowered, the shutdown sequence happens by powering of the SIM_RST channel. Once that is achieved, SIM_CLK, SIM_I/O and VSIM are then powered sequentially one by one. There is an internal 2K pull-down value on the SIM pins, and this helps to pull the channels low. The shutdown time sequence is ordered to a few microseconds. EN needs to be lowered first for the shutdown to occur, which will then control the SIM IO, RST, and CLK. When EN and VCC are both lowered, the shutdown sequence will not be triggered.