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Small green circuit board with surface-mount chip and header pins

Adafruit

Adafruit KA75330 3.3V Voltage Detector engineering development tool

SKU CH-FG7A-929AB

Monitors input voltage and pulls the output low when it drops below 3.3 V, protecting microcontrollers with an enable pin

  • Product typePrototyping Products
  • Ensures microcontroller runs only above 3.3V
  • Detects voltage drop and pulls output low
  • Operates from supply as low as 0.8V
  • Designed for boards with Enable pin
  • Prevents lockups and data corruption at low voltage

Low-voltage microcontroller guard

The Adafruit KA75330 monitors a supply rail and pulls its output low when voltage drops below 3.3 V. It begins operating from as little as .8 V, so it can protect a board even during deep discharge. The device suits any project that must prevent a microcontroller from running at an unsafe level.

Check your board for an enable pin

This detector works best with microcontrollers or development boards that expose an Enable pin. Verify that your target board provides such a pin and that pulling it low will halt the processor. Also confirm that the monitored rail is the one feeding the microcontroller core.

Ideal for battery-powered feather boards

Builders running ESP8266 or similar cores on lipoly cells will benefit from the automatic shutdown before lock-up or data corruption occurs. It is less suited for designs without an accessible enable input or for systems that already include a built-in brownout circuit.

How it compares

Measured against everything we stock in Engineering Workstations & Dev Kits, at today’s prices. Recalculated every night.

Price $4.99
Cheaper than about 93% of the 170 comparable items (median $11.49).

Specifications

Product
Product typePrototyping Products

Questions about this item

Does the KA75330 package include any headers, cables or a PCB, or must they be sourced separately?

The KA75330 is supplied as the bare voltage-detector chip only; headers, cables and a carrier PCB are not included and must be obtained separately.

What is the difference between the 3.3 V threshold of the KA75330 and other available detector voltages?

The KA75330 triggers at 3.3 V, making it suitable for 3.3 V logic systems such as the ESP8266; detectors with different thresholds are separate part numbers.

How does the 0.8 V minimum operating voltage of the KA75330 affect behaviour when a LiPo battery is deeply discharged?

The detector remains active down to 0.8 V, so it continues to hold the Enable pin low and prevents the microcontroller from starting until the supply recovers above 3.3 V.

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