D30V30F9 9V Step-Down Regulator (9–45V In, 2.9A) + EN & Power-Good

Need a clean 9V rail from a higher-voltage source (2S/3S/6S packs, 12V/24V systems, industrial supplies)? The Pololu D30V30F9 is a compact synchronous buck (step-down) regulator that converts 9–45V input to a fixed 9V output with high efficiency. It’s a solid upgrade vs linear regulators when the voltage drop is large—less heat, better battery life.

Built for real projects: reverse-voltage protection, UVLO, over-current/short protection, thermal shutdown, and soft-start.

Perfect for

9V sensor / radio / audio rails from 12V–24V supplies
Robotics power (servos/logic rails that need stable 9V)
Portable rigs where efficiency + heat control matter
Projects that want enable/sleep control + a power-good signal

Pro tip: Use EN to shut the regulator down for low-power standby, and use PG (power-good) to detect when the module can’t maintain regulation (requires an external pull-up).

Why/Benefits

Efficient 9V from high input: switching regulator design reduces heat vs linear regulators.
Enable / sleep control: disconnect load and enter low-power mode (great for battery builds).
Power-good output: lets your MCU know when 9V is out of spec (brownout / overload detection).
Protection built in: UVLO, over-current, short-circuit, thermal shutdown, soft-start.
Compact + mountable: small footprint with mounting holes for clean installs.

Technical specifications

Model	D30V30F9 (Fixed 9V)
Input voltage	9V to 45V (minimum VIN depends on dropout under load)
Output voltage	9V fixed (±4% accuracy)
Typical max continuous current	2.9A (at 30V in; actual depends on VIN, airflow, and heat)
Typical efficiency	80% to 95% (depends on VIN/load)
Switching frequency	~700 kHz under heavy loads (with power-save mode at light loads)
Reverse voltage protection	Yes (up to 40V reverse; avoid >40V reverse connection)
Quiescent current	Up to ~13 mA (enabled). Sleep mode via EN draws ~10–20 µA per volt on VIN
Size / weight	0.7″ × 0.8″ × 0.35″; ~3.3 g (without headers)

Pinout & power notes

VIN: connect your input supply here (9–45V). Use thicker wires for high current.
VOUT: regulated 9V output.
GND (x2): two ground pins for easier wiring.
EN (Enable): enabled by default; pull low to enter low-power sleep/disable state.
PG (Power-Good): open-drain output; add a pull-up resistor if you want to read it with an MCU.

FAQ

Can I use this on a 12V or 24V supply?

Yes—those are common use cases. Just keep wiring short/thick for higher currents and provide airflow if running near max output.
How do I use the Power-Good (PG) pin?

PG is open-drain: add an external pull-up (to 3.3V or 5V logic) and read it as a digital status signal.
Can EN be used as an on/off control?

Yes—drive EN from a switch or MCU pin to disable the regulator and reduce standby draw.