SCPS277B November   2022  – November 2023 TCAL6408

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 I2C Bus Timing Requirements
    8. 5.8 Switching Characteristics
    9. 5.9 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Voltage Translation
      2. 7.3.2 I/O Port
      3. 7.3.3 Adjustable Output Drive Strength
      4. 7.3.4 Interrupt Output (INT)
      5. 7.3.5 Reset Input (RESET)
      6. 7.3.6 Software Reset Call
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power-On Reset
    5. 7.5 Programming
      1. 7.5.1 I2C Interface
    6. 7.6 Register Maps
      1. 7.6.1 Device Address
      2. 7.6.2 Control Register and Command Byte
      3. 7.6.3 Register Descriptions
      4. 7.6.4 Bus Transactions
        1. 7.6.4.1 Writes
        2. 7.6.4.2 Reads
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Minimizing ICC When I/Os Control LEDs
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Power-On Reset Requirements
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

7.1 Overview

The TCAL6408 supports voltage translation over a of a wide supply voltage range. This allows the device to interface with modern processors on the I2C side, where supply levels are lower to conserve power. In contrast to the dropping power supplies of processors, some PCB components such as LEDs still require a higher voltage power supply.

The VCCI pin is the power supply for the I2C bus, and therefore the pull-up resistors connected to the SCL, SDA, and RESET pins should be terminated at VCCI. The INT output has an open-drain structure and requires an external pull-up resistor to VCCP or VCCI depending on the application. The VCCP pin is the power supply for the P-ports. If external pull-up resistors are used on any P-port, or LEDs are driven by any P-port, then the resistor(s) or LED(s) connected to P0-P7 should be terminated at VCCP. The device P-ports configured as outputs have the ability to sink up to 25 mA for directly driving LEDs, but the current must be limited externally with an additional resistance.

The TCAL6408 digital core consists of 8-bit data registers which allow the user to configure the I/O port characteristics. At power on or after a reset, the I/Os are configured as inputs. However, the system controller can configure the I/Os as either inputs or outputs by writing to the Configuration registers. The data for each input or output is kept in the corresponding Input Port or Output Port register. The polarity of the Input Port register can be inverted with the Polarity Inversion register. All registers can be read by the system controller. Additionally, the TCAL6408 has Agile I/O functionality which is specifically targeted to enhance the I/O ports. The Agile I/O features and registers include programmable output drive strength, programmable pull-up and pull-down resistors, latchable inputs, maskable interrupts, interrupt status register, and programmable open-drain or push-pull outputs. These configuration registers improve the I/O by increasing flexibility and allowing the user to optimize their design for power consumption, speed, and EMI.

Other features of the device include an interrupt that is generated on the INT pin whenever an input port changes state. The device can be reset to its default state by applying a low logic level to the RESET pin, issuing a software reset command, or by cycling power to the device and causing a power-on reset. The ADDR hardware selectable address pin allows two TCAL6408 devices to be connected to the same I2C bus.

The TCAL6408 open-drain interrupt (INT) output is activated when any input state differs from its corresponding Input Port register state and is used to indicate to the system controller that an input state has changed. The INT pin can be connected to the interrupt input of a processor. By sending an interrupt signal on this line, the device can inform the processor if there is incoming data on the remote I/O ports without having to communicate via the I2C bus. Thus, the device can remain a simple responder device.

The system controller can reset the device in the event of a timeout or other improper operation by asserting a low on the RESET input pin or by cycling the power to the VCCP pin and causing a power-on reset (POR). A reset puts the registers in their default state and initializes the I2C /SMBus state machine. The RESET feature and a POR cause the same reset/initialization to occur, but the RESET feature does so without needing to power down the device.

One hardware pin (ADDR) can be used to program and vary the fixed I2C address, and allow two devices to share the same I2C bus or SMBus.