SNAS809A December   2021  – August 2022 REF35

PRODUCTION DATA  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Device Comparison
  6. Pin Configuration and Functions
  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 Typical Characteristics
  8. Parameter Measurement Information
    1. 8.1 Solder Heat Shift
    2. 8.2 Temperature Coefficient
    3. 8.3 Long-Term Stability
    4. 8.4 Thermal Hysteresis
    5. 8.5 Noise Performance
      1. 8.5.1 Low-Frequency (1/f) Noise
      2. 8.5.2 Broadband Noise
    6. 8.6 Power Dissipation
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Supply Voltage
      2. 9.3.2 EN Pin
      3. 9.3.3 NR Pin
    4. 9.4 Device Functional Modes
      1. 9.4.1 Basic Connections
      2. 9.4.2 Start-Up
      3. 9.4.3 Output Transient Behavior
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Negative Reference Voltage
      2. 10.2.2 Precision Power Supply and Reference
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
          1. 10.2.2.2.1 Selection of Reference
          2. 10.2.2.2.2 Input and Output Capacitors
          3. 10.2.2.2.3 Selection of ADC
        3. 10.2.2.3 Application Curves
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

EN Pin

The REF35 family supports device enable and disable functionality through logic level control on EN pin. The EN pin of REF35 does not use an internal pull-up resistor. Instead, the pin uses new 'clean EN' technology. This allows the EN pin to be in a no connect condition at start-up, and no extra current is drawn from the supply when the EN pin is pulled low in shutdown mode. When EN pin is pulled high or left unconnected at start-up, the device is in active mode. When EN pin is driven by an open-drain output, a pull-up resistor to VIN is required. The device must be in active mode for normal operation. The EN pin must not be pulled higher than VIN supply voltage.

The device can be placed in shutdown mode by pulling the EN pin low. When in shutdown mode, the output of the device becomes high impedance and the quiescent current of the device drops to 100 nA at room temperature. When changing the device state from shutdown to active state, ensure the EN pin is not left floating.

Also note that for applications where EN pin is no-connect, total parasitic capacitance on EN pin should be restricted within 30 pF.

See the Section 7.5 table for logic high and logic low voltage levels.