SNAU276A January   2022  – November 2023

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Overview
    1. 1.1 REF35EVM Features
    2. 1.2 REF35EVM Schematic
    3. 1.3 REF35EVM Bill of Materials
    4. 1.4 REF35EVM Board
  5. 2Quick Setup Guide
    1. 2.1 Electrostatic Discharge Warning
    2. 2.2 Power Supply Setup and Functional Test
  6. 3Layout
  7. 4Revision History

2.2 Power Supply Setup and Functional Test

Normal operation:

If directly connecting the REF35 to the lab supply, a A 5-V power supply capable of 50 mA of current is required (to handle load transients). Set the Power Select jumpers to Lab. The REF35 consumes 1.4 uA of current during normal operating and has a maximum 10 mA of output current for maintaining regulated voltage. During start-up, the REF35 can momentarily consume ISC to charge the output capacitors.

Connect the positive power supply lead to the VIN_REF pin on the REF Power header pin on the left side of the board. Connect the negative power supply lead to the GND pin on the REF Power header pin.

If powering the REF35 through the on-EVM LDO, an A 5-V (up to the LDO max voltage, 40 V) power supply capable of 50 mA of current is required. Set the Power Select jumpers to LDO.

Connect the positive power supply lead to the VIN_REF pin on the REF Power header pin on the left side of the board. Connect the negative power supply lead to the GND pin on the REF Power header pin.

This EVM features selectable loads, where the loads are pulled to GND or VCC.

Connect a voltmeter to the VREF pin on the right side of the board. Connect the negative voltmeter terminal to GND. An SMA cable can also be used to measure the same output.

Note: Test points TP8, TP9, TP10, and TP11 are not soldered to the ground plane. The user can connect TP8, TP9, TP10, and TP11 to an external source ground if desired. Additionally, SMA connector J1 is not soldered to the ground plane.

The output voltage of the REF35125QDBVR is 1.25 V.

Shutdown mode: Move the jumper pin from EN to SHDN to place the part in shutdown mode. The REF35 is in active mode if the jumper pin is either in EN or not present.