SBVS301B October   2016  – September 2021 TPS3850

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Timing Requirements
    7. 6.7 Timing Diagrams
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 CRST
      2. 7.3.2 RESET
      3. 7.3.3 Over- and Undervoltage Fault Detection
      4. 7.3.4 Adjustable Operation Using the TPS3850H01
      5. 7.3.5 Window Watchdog
        1. 7.3.5.1 SET0 and SET1
          1. 7.3.5.1.1 Enabling the Window Watchdog
          2. 7.3.5.1.2 Disabling the Watchdog Timer When Using the CRST Capacitor
          3. 7.3.5.1.3 SET0 and SET1 During Normal Watchdog Operation
      6. 7.3.6 Window Watchdog Timer
        1. 7.3.6.1 CWD
        2. 7.3.6.2 WDI Functionality
        3. 7.3.6.3 WDO Functionality
    4. 7.4 Device Functional Modes
      1. 7.4.1 VDD is Below VPOR ( VDD < VPOR)
      2. 7.4.2 Above Power-On-Reset But Less Than UVLO (VPOR ≤ VDD < VUVLO)
      3. 7.4.3 Above UVLO But Less Than VDD (min) (VUVLO ≤ VDD < VDD (min))
      4. 7.4.4 Normal Operation (VDD ≥ VDD (min))
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 CRST Delay
        1. 8.1.1.1 Factory-Programmed Reset Delay Timing
        2. 8.1.1.2 Programmable Reset Delay-Timing
      2. 8.1.2 CWD Functionality
        1. 8.1.2.1 Factory-Programmed Timing Options
        2. 8.1.2.2 Adjustable Capacitor Timing
      3. 8.1.3 Adjustable SENSE Configuration
      4. 8.1.4 Overdrive on the SENSE Pin
    2. 8.2 Typical Applications
      1. 8.2.1 Design 1: Monitoring a 1.2-V Rail with Factory-Programmable Watchdog Timing
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Monitoring the 1.2-V Rail
          2. 8.2.1.2.2 Meeting the Minimum Reset Delay
          3. 8.2.1.2.3 Setting the Watchdog Window
          4. 8.2.1.2.4 Calculating the RESET and WDO Pullup Resistor
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Design 2: Using TPS3850H01 to monitor a 0.7-V Rail With an Adjustable Window Watchdog Timing
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Meeting the Minimum Reset Delay
          2. 8.2.2.2.2 Setting the Window Watchdog
          3. 8.2.2.2.3 Watchdog Disabled During the Initialization Period
          4. 8.2.2.2.4 Calculating the Sense Resistor
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Device Nomenclature
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

6.6 Timing Requirements

MINTYPMAXUNIT
GENERAL
tINITCWD, CRST pin evaluation period(1)381µs
tSETTime required between changing SET0 and SET1 pins500µs
SET0, SET1 pin setup time1µs
Startup delay(2)300µs
RESET FUNCTION
tRSTReset timeout periodCRST = NC170200230ms
CRST = 10 kΩ to VDD8.51011.5ms
tRST-DELVSENSE to RESET delayVDD = 5 V, VSENSE = VIT+(OV) + 2.5%35µs
VDD = 5 V, VSENSE = VIT-(UV) – 2.5%17
WINDOW WATCHDOG FUNCTION
WD ratioWindow watchdog ratio of lower boundary to upper boundaryCWD = programmable, SET0 = 0, SET1 = 0(3)1/8
CWD = programmable, SET0 = 1, SET1 = 1(3)1/2
CWD = programmable, SET0 = 0, SET1 = 1(3)(4)3/4
tWDLWindow watchdog lower boundaryCWD = NC, SET0 = 0, SET1 = 019.122.525.9ms
CWD = NC, SET0 = 0, SET1 = 11.481.852.22ms
CWD = NC, SET0 = 1, SET1 = 0Watchdog disabled
CWD = NC, SET0 = 1, SET1 = 1680800920ms
CWD = 10 kΩ to VDD, SET0 = 0, SET1 = 07.659.010.35ms
CWD = 10 kΩ to VDD, SET0 = 0, SET1 = 17.659.010.35ms
CWD = 10 kΩ to VDD, SET0 = 1, SET1 = 0Watchdog disabled
CWD = 10 kΩ to VDD, SET0 = 1, SET1 = 11.481.852.22ms
tWDUWindow watchdog upper boundaryCWD = NC, SET0 = 0, SET1 = 046.855.063.3ms
CWD = NC, SET0 = 0, SET1 = 123.37527.531.625ms
CWD = NC, SET0 = 1, SET1 = 0Watchdog disabled
CWD = NC, SET0 = 1, SET1 = 1136016001840ms
CWD = 10 kΩ to VDD, SET0 = 0, SET1 = 092.7109.0125.4ms
CWD = 10 kΩ to VDD, SET0 = 0, SET1 = 1165.8195.0224.3ms
CWD = 10 kΩ to VDD, SET0 = 1, SET1 = 0Watchdog disabled
CWD = 10 kΩ to VDD, SET0 = 1, SET1 = 19.3511.012.65ms
tWD-setupSetup time required for device to respond to changes on WDI after being enabled150µs
Minimum WDI pulse duration50ns
tWD-delWDI to WDO delay50ns
(1) Please refer to Section 8.1.1.2
(2) During power-on, VDD must be a minimum 1.6 V for at least 300 µs before the output corresponds to the SENSE voltage.
(3) 0 refers to VSET ≤ VIL, 1 refers to VSET ≥ VIH.
(4) If this watchdog ratio is used, then tWDL(max) can overlap tWDU(min).