Skip to the beginning of the images gallery

Soft Power Switch Mk2 - JST 2mm

SKU: SPX-25365 Brand: Sparkfun

The Soft Power Switch Mk2 is a passive, hard on/off switch with software feedback and control. In other words, it's like the on/off switch on a laptop. A s...

Special Price $8.88 AUD, inc GST

Regular Price $11.09 AUD, inc GST

$8.07 AUD, exc GST

Special pricing ends 17 March 2025

* this special may end earlier than shown

Available with a lead time
Expect dispatch between Dec 26 and Dec 30

The Soft Power Switch Mk2 is a passive, hard on/off switch with software feedback and control. In other words, it's like the on/off switch on a laptop. A simple press will turn the system on. Another press can (with MCU intervention) turn off the system. And if things go really wrong, pressing and holding the button for ~10 seconds will force a power-down. If you're building something with an enclosed battery and need a good power button, this is the board you need.

The Mk1 Soft Power Switch is great, but Sparkfun do see occasional issues caused by component tolerances or the operating temperature. Mk2 is based on an application note by Texas Instruments, and is a completely digital design. It is based around a 74LVC1G175 D-type flip-flop - remember those?! - and is insensitive to temperature and component variation. It also includes improvements like: an over-current self-resetting 2A fuse; input and output LEDs. This version has JST 2mm battery connector.

The PUSH pin can act as an output to a microcontroller indicating the state of the power button (high = not pressed, low = user is pressing power button). This can be used as an input to your firmware to begin to shut down before power is lost. Alternatively, the OFF pin can be driven high by the system forcing fast power off via software. (For Mk1, the Fast Off pin was driven low.)

The most common use case is something like this:

Microcontroller begins running code and checks to see if the power button is still being pressed for X milliseconds.
If not, it's just a tap, go back to sleep.
If yes, power up and run normal program.

Later...

User presses power button in normal program
If power button is pressed for <X milliseconds, it's just a tap, ignore.
If power button is pressed for >X milliseconds, it's time to power down.

The wake-up and power-down times can be tweaked for your own user experience but Sparkfun found 500ms for power up and 2s for power down work really well.

If needed, pads are provided for a larger, external button.

The Soft Power Switch supports battery charging. If the target device has onboard LiPo charging, current can be passed back through the switch circuit and charge the battery.

Heads up! The Mk2 Soft Power Switch works up to 5.5V only. (Mk1 is good up to 12V.)

Pros:

Very low quiescent current: <1µA @ 3.75V, with VIN LED disabled
Hard override power down in case your microcontroller loses its mind
PUSH and OFF pins can be connected to a microcontroller
Supports battery charging

Cons:

Limited to 2A continuous, 4A peak (fuse protected)
No AC loads

We do not plan to regularly produce SparkX products so get them while they’re hot!

Experimental Product: SparkX products are rapidly produced to bring you the most cutting edge technology as it becomes available. These products are tested but come with no guarantees. Live technical support is not available for SparkX products. Head on over to our forum for support or to ask a question.

Features

Input voltage: 5.5V maximum, 1.8V minimum
Maximum current draw: 2A continuous, 4A peak (fuse protected)
Very low quiescent current: <1µA @ 3.75V, with VIN LED disabled
Hard override: push and hold the button for ~10 seconds
Supports battery charging
1" x 1" PCB
LEDs: VIN and VOUT (can be disabled if desired)
Breakouts:
- GND, VIN, VOUT
- BTN: if desired, connect an external button between BTN and GND
- PUSH: open-drain output, requires pull-up, low indicates button is pushed
- OFF: drive high to turn the output off

Documents

This product is listed in:

Power & Batteries>Others

Product Comments

Start the conversation

Exact shipping can be calculated on the view cart page (no login required).

Products that weigh more than 0.5 KG may cost more than what's shown (for example, test equipment, machines, >500mL liquids, etc).

We deliver Australia-wide with these options (depends on the final destination - you can get a quote on the view cart page):

$3+ for Stamped Mail (typically 10+ business days, not tracked, only available on selected small items)
$7+ for Standard Post (typically 6+ business days, tracked)
$11+ for Express Post (typically 2+ business days, tracked)
Pickup - Free! Only available to customers who live in the Newcastle region (must order online and only pickup after we email to notify you the order is ready). Orders placed after 2PM may not be ready until the following business day.

Non-metro addresses in WA, NT, SA & TAS can take 2+ days in addition to the above information.

Some batteries (such as LiPo) can't be shipped by Air. During checkout, Express Post and International Methods will not be an option if you have that type of battery in your shopping cart.

International Orders - the following rates are for New Zealand and will vary for other countries:

$12+ for Pack and Track (3+ days, tracked)
$16+ for Express International (2-5 days, tracked)

If you order lots of gear, the postage amount will increase based on the weight of your order.

Our physical address (here's a PDF which includes other key business details):

Unit 18, 132 Garden Grove Parade
Adamstown
NSW, 2289
Australia

Take a look at our customer service page if you have other questions such as "do we do purchase orders" (yes!) or "are prices GST inclusive" (yes they are!). We're here to help - get in touch with us to talk shop.

Have a product question? We're here to help!