Review Request: ADP7102 and ADP7182 +-2.5V Implementation

Hello Analog Devices Engineers,

I am implementing the ADP7102 (+2.5V) and ADP7182 (-2.5V) LDOs to generate ±2.5V rails for an op-amp circuit. The op-amp’s total current consumption is expected to be no more than 20 mA. I would appreciate feedback on my implementation to ensure proper operation (I'm somewhat new to designing analog circuitry.)

Implementation Details:

• Power Setup:

  • ADP7102 provides +2.5V relative to VGND.
  • ADP7182 provides -2.5V relative to VGND.
  • Both LDOs receive +12V (for ADP7102) and -12V (for ADP7182) as input voltages.
  • EXTERNAL_PWR_VGND is supplied by GoldPoint Level Controls' VG2 circuit.

• Enable Pin Configuration:

  • I want the LDOs to be always on.
  • I have tied the enable (EN) pins to VIN and would like to confirm if this is correct.

• Input/Output Capacitors:

  • I have implemented 10 uF ceramic input and output capacitors based on the recommendations from the datasheets. The datasheet suggests a lower capacitance value, but because my capacitors are under a bias, I've increased their capacitance such that their effective capacitance is close to the recommended value of 2.2 uF.
  • I would like to confirm that I'm using the best capacitor value and type -- would you recommend additional capacitors or use of capacitors with a different ESR value?

• Bleed Resistors:

  • I have added bleed resistors to ensure the LDOs consume a minimum load at all times.
  • I would like to confirm whether these resistors are necessary (i.e., if I have to consume a minimum load -- not consuming a minimum load has been a problem for me with other LDO's) and, if so, whether their values are appropriate.

Request for Feedback:

• Are my enable pin connections correct for keeping the LDOs always on?
• Does my capacitor selection ensure proper stability and transient response?
• Are my bleed resistors necessary, and are their values reasonable?

I have attached a screenshot of my schematic showing the full implementation for reference.

I appreciate your time and expertise—thank you in advance for your guidance! The schematic is below:

Thank you for your time and expertise,

-Arjun