Pololu Isolated Solid State Relay/Switch — SPST, 30V, 11A

A compact, silent “electronic relay” for switching DC loads—without the clicking, contact wear, or arcing of mechanical relays. The Pololu Isolated Solid State Relay/Switch is an SPST switch controlled by a low-current signal (2.7V to 40V) and uses an optically isolated driver to galvanically isolate the control side from the load side. The output stage is a back-to-back MOSFET pair, making the two load terminals symmetric—so it can be used as a high-side or low-side switch in either orientation.

Rated for DC switching: up to 30V load voltage and 11A load current (absolute maximum).
Low losses: typical combined MOSFET resistance around 10 mΩ when enabled.
Fast enough for switching tasks: turn-on up to 1.5 ms, turn-off up to 1 ms.
Small form factor: about 0.8″ × 0.32″ × 0.13″, ~0.4 g.

Important notes (helps prevent wrong expectations):

Not for high-speed PWM: switching times are around 1 ms, so it’s not suited for signaling much beyond a few hundred transitions per second.
Control current: when enabled, the control circuit can draw up to 10 mA from VIN. If your signal source can supply that, you can tie EN and VIN together for simple 2-wire control.
Real-world current: Pololu’s testing showed this 30V version could conduct about 11A continuously at ~25°C with no forced airflow before hitting thermal limits.

Why/Benefits

Modern relay replacement

Silent switching (no relay click)
No mechanical contacts to wear out or arc
Compact footprint for tight enclosures

Flexible wiring + isolation

Optical isolation separates logic/control from load wiring
Bidirectional, symmetric load terminals (use as high-side or low-side)
Output pads support soldered wires or terminal blocks (3.5mm/5mm pitch)

Technical specifications

Product	Pololu Isolated Solid State Relay/Switch, SPST, 30V, 11A
Control voltage (VIN / EN high)	2.7V to 40V
Max input current	10 mA (on VIN when EN is high)
Max load voltage	30V (absolute max)
Max load current	11A (absolute max)
On-resistance	10 mΩ (typical combined; listed max on resistance 10 mΩ)
Switching times	Turn-on ≤ 1.5 ms, Turn-off ≤ 1 ms
Isolation method	Optically isolated driver (galvanic isolation between control and load)
Dimensions	0.8″ × 0.32″ × 0.13″
Weight	0.4 g

Pinout & power notes

VIN, GND: powers the control side (2.7–40V).
EN: drive high (2.7–40V) to turn the switch ON.
2-wire option: if your control source can supply up to ~10 mA, you can tie EN to VIN to make it “power-on = ON”.
LOAD terminals: symmetric MOSFET outputs; use either orientation (high-side or low-side switching).

FAQ

Can I use this as a high-side switch

Yes. The back-to-back MOSFET output is symmetric, so you can place it on the high side or low side in either orientation.
Can my microcontroller pin drive EN directly?

EN needs a “high” between 2.7V and 40V, and the control circuit can draw up to ~10 mA when enabled. If your GPIO can’t supply that, drive EN through a suitable transistor/driver stage.
Is it good for PWM motor speed control?

Not for high-frequency PWM. Switching times are ~1 ms, so it’s best for ON/OFF control and low-rate switching.

Pololu Isolated Solid State Relay/Switch, SPST, 30V, 11A

Name: Pololu Isolated Solid State Relay/Switch, SPST, 30V, 11A
Brand: circuitrocks
SKU: POL5421
Price: 356.0 PHP
Availability: InStock