SLVSF29C October   2019  – August 2021 TPS8804

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 System Power-up
      2. 7.3.2 LDO Regulators
        1. 7.3.2.1 Power LDO Regulator
        2. 7.3.2.2 Internal LDO Regulator
        3. 7.3.2.3 Microcontroller LDO Regulator
      3. 7.3.3 Photo Chamber AFE
        1. 7.3.3.1 Photo Input Amplifier
        2. 7.3.3.2 Photo Gain Amplifier
      4. 7.3.4 LED Driver
        1. 7.3.4.1 LED Current Sink
        2. 7.3.4.2 LED Voltage Supply
      5. 7.3.5 Carbon Monoxide Sensor AFE
        1. 7.3.5.1 CO Transimpedance Amplifier
        2. 7.3.5.2 CO Connectivity Test
      6. 7.3.6 SLC Interface Transmitter and Receiver
        1. 7.3.6.1 SLC Transmitter
        2. 7.3.6.2 SLC Receiver
      7. 7.3.7 AMUX
      8. 7.3.8 Analog Bias Block and 8 MHz Oscillator
      9. 7.3.9 Interrupt Signal Alerts
    4. 7.4 Device Functional Modes
      1. 7.4.1 Fault States
        1. 7.4.1.1 MCU LDO Fault
        2. 7.4.1.2 Over-Temperature Fault
    5. 7.5 Programming
    6. 7.6 Register Maps
      1. 7.6.1  REVID Register (Offset = 0h) [reset = 0h]
      2. 7.6.2  STATUS1 Register (Offset = 1h) [reset = 0h]
      3. 7.6.3  STATUS2 Register (Offset = 2h) [reset = 0h]
      4. 7.6.4  MASK Register (Offset = 3h) [reset = 0h]
      5. 7.6.5  CONFIG1 Register (Offset = 4h) [reset = 20h]
      6. 7.6.6  CONFIG2 Register (Offset = 5h) [reset = 0h]
      7. 7.6.7  ENABLE1 Register (Offset = 6h) [reset = 0h]
      8. 7.6.8  ENABLE2 Register (Offset = 7h) [reset = 0h]
      9. 7.6.9  CONTROL Register (Offset = 8h) [reset = 0h]
      10. 7.6.10 GPIO_AMUX Register (Offset = Bh) [reset = 0h]
      11. 7.6.11 COSW Register (Offset = Ch) [reset = 0h]
      12. 7.6.12 CO Register (Offset = Dh) [reset = 0h]
      13. 7.6.13 LEDLDO Register (Offset = Fh) [reset = 0h]
      14. 7.6.14 PH_CTRL Register (Offset = 10h) [reset = 0h]
      15. 7.6.15 LED_DAC_A Register (Offset = 11h) [reset = 0h]
      16. 7.6.16 LED_DAC_B Register (Offset = 12h) [reset = 0h]
  8. 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 Photo Amplifier Component Selection
        2. 8.2.2.2 LED Driver Component Selection
        3. 8.2.2.3 LED Voltage Supply Selection
        4. 8.2.2.4 Regulator Component Selection
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Photo Amplifier Layout
      2. 10.1.2 CO Amplifier Layout
      3. 10.1.3 Ground Plane Layout
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.4.2 LED Voltage Supply

Enough voltage must be provided to the LED such that the DINA voltage is at least the dropout voltage (VDINA,DROP) above the CSA voltage while the LED driver is enabled. Ensure the DINA voltage does not exceed 11.5 V. Because of the high LED drive currents, a large capacitor connected to the LED anode is required to provide pulsed power to the LED. Any of the internal regulators ( PLDO, LEDLDO) or external supply ( VDC) meeting the voltage requirements can be used to charge the LED capacitor. Connect the LED anode to LEDLDO when VCC > 11.5 V.

The LED LDO clamps the VSLC voltage and blocks reverse current with an integrated diode. It is current limited to prevent inrush current caused by charging the large capacitor. The regulation voltage is adjustable in the LEDLDO register. The LED LDO may be operated with VSLC below the regulation voltage. In this case, the LEDLDO voltage stabilizes to VSLC minus a diode voltage drop.

The LED driver current and rise time can vary by a few millivolts and microseconds across the LED anode supply and VCC voltages. It is recommended to use a consistent LED anode voltage whenever the LED driver is enabled.

Connect a capacitor with a value between 1 µF and 100 µF to the LEDLDO.