SparkFun sm�´l Power Board LiPo

Our RedBoards are great. But don't they sometimes seem a little BIG?!

Enter sm�´l, a new range of boards which are both small in size and small on current draw. It's a sm�´l world!

The smÃ�´l Power Board LiPo is an intelligent power board for the smÃ�´l ecosystem. You would expect this board to have an MCP73831 Li-Ion and Li-Polymer charger on it, and indeed it does. You would also expect this board to have a MAX17048 I²C fuel gauge on it, and indeed it does. But you probably wouldn't expect it to have an AVR ATtiny841 microcontroller on it. So why have we included one?

This is an intelligent power board for smÃ�´l. The power board takes control of the 3.3V power for the whole smÃ�´l stack. The processor board can then instruct the power board to put the entire smÃ�´l stack into deep sleep for a pre-defined interval. Sleep intervals of 10's of milliseconds to several days are possible. In deep sleep, the only device left powered is the ATtiny841 and that reduces the current draw to 6µA. Yes, you read that right, 6 microamps! smÃ�´l makes it possible for your battery life to be measured in months not days! We used the fantastic Otii Arc Power Analyzer to help us reduce the sleep current as much as possible.

Our sm�´l Power Board Arduino Library has examples to get you started.

sm�´l is an ecosystem of miniature processor boards, peripheral boards, power boards and accessories. Designed to be both physically small and to have the smallest possible current draw, sm�´l is the perfect choice for applications like wildlife tracking or discrete long-term monitoring. sm�´l boards are designed to stack one on top of the other, using 16-way 0.5mm-pitch Flexible Printed Circuits (FPCs) to provide the interconnect from one board to the next. Looking for a really compact solution for your next project? This is it!

We will be adding new sm�´l boards over the coming months. Don't see the board you need for your application? Reach out to us via the SparkX Forum and tell us which board(s) we should add next!

Features:

Li-Ion / Li-Polymer Charger:

• MCP73831
  • Charge current: 100mA (when USB power is connected)

Battery Fuel Gauge:

• MAX17048

On-Board Microcontroller:

• ATtiny841 8-bit AVR Microcontroller
  • 8KBytes Flash
  • 512Bytes EEPROM
  • 512Bytes SRAM

Power Regulation:

• smÃ�´l 3.3V:
  • AP2112K-3.3V
  • I_OUT (max): 600mA
  • I_Q: 55µA
• ATtiny841 3.3V:
  • STLQ015-3.3V
  • I_OUT (max): 150mA
  • I_Q: 1.4µA

Sleep Current Draw:

• 6µA (with ATtiny841 in Power-Down Mode) (measured by Otii Arc)

sm�´l Specifics:

• Interface: I²C
  • ATtiny841 Default Address: 0x50
  • MAX17048 Fuel Gauge Address: 0x36
• PROC_PWR_EN:
  • The power board pulls PROC_PWR_EN low to disable the regulator on the processor board

Properties:

• Length: 1.60" (40.6mm)
• Width: 0.42" (10.7mm)
• Height: 0.29" (7.4mm) max.
• Weight: 1.4g (0.05oz)
• PCB thickness: 0.8mm

Documents:

sm�´l Power Board LiPo Documentation:

• Schematic
• Eagle Files
• Hookup Guide
• GitHub Hardware Repo
• SparkFun smÃ�´l Power Board Arduino Library
• Arduino Examples

Li-Ion / Li-Polymer Charger:

• Datasheet (MCP73831)

Battery Fuel Gauge:

• Datasheet (MAX17048)

Microcontroller:

• Datasheet (ATtiny841)

sm�´l Documentation:

• smÃ�´l Hookup Guide