Alex Cornejo edited this page Jun 9, 2014 · 8 revisions

Required parts

The DigiKey/Manufacturer part numbers are only for reference. All parts can be replaced by functional equivalents.

Designator Package Quantity Designation Manuf. Part Digikey Ref.
R1,R2 SM0402 2 33 Stackpole Electronics Inc RMCF0402JT33R0 RMCF0402JT33R0CT-ND
R3 SM0402 1 1k Stackpole Electronics Inc RMCF0402JT1K00 RMCF0402JT1K00CT-ND
C1,C2 SM0402 2 2.2u >=6.3V Samsung CL05A225MQ5NNNC 1276-1469-2-ND
C3,C4,C5,C6 SM0402 4 0.1u >=6.3V Samsung CL05A104MP5NNNC 1276-1443-2-ND
D1 LED-0603 1 LED, any color, any brightness Osram LY Q976-P1S2-36 475-2558-1-ND
U1 LQFP48 1 MCU Kinets K20 48-QFP Freescale MK20DX32VLF5 MK20DX32VLF5-ND
S1 EVQP2 1 button, any ~4mm*3mm button (or similar) C&K Components PTS810 SJM 250 SMTR LFS CKN10502CT-ND
J3 1 Micro USB AB receptacle FCI 10104111-0001LF 609-4053-1-ND
PCB 1 50mm*19mm, 2mm thickness, ENIG

Optional parts

RTC

Designator Package Quantity Designation Manuf. Part Digikey Ref.
Y1 Cylindrical Can, Radial (2.10mm x 6.20mm) 1 Crystal 32.768kHz Abracon AB26T-32.768KHZ 535-9032-ND

Noise reduction

Designator Package Quantity Designation Manuf. Part Digikey Ref.
FB1 0603 1 Ferrite bead TDK MMZ1608B601C 445-2166-1-ND
C9 0603 1 100n >=6.3V Samsung CL10B104KO8NNNC 1276-1005-1-ND

VREF out

Designator Package Quantity Designation Manuf. Part Digikey Ref.
C8 0603 1 100n >=6.3V Samsung CL10B104KO8NNNC 1276-1005-1-ND

Boost regulator for single cell battery (AAA) operation

Designator Package Quantity Designation Manuf. Part Digikey Ref.
U4 SOT-23-5 1 Boost regulator TI TPS61097-33DBVT 296-24656-1-ND
L1 0805 1 4.7u >200mA Samsung CIG21L4R7MNE 1276-6204-1-ND
C11,C12 0805 2 10u >=4V, X5R Yageo CC0805KKX5R5BB106 311-1459-1-ND
  • Alternative regulator: Maxim MAX1724

Buck regulator

Designator Package Quantity Designation Manuf. Part Digikey Ref.
U4 SOT-23-5 1 Buck regulator TI LM3670MF-3.3/NOPB LM3670MF-3.3/NOPBCT-ND
L1 0805 1 4.7u >200mA Samsung CIG21L4R7MNE 1276-6204-1-ND
C11,C12 0805 2 10u >=4V, X5R Yageo CC0805KKX5R5BB106 311-1459-1-ND

(other regulators?)

Linear regulator for 16V operation

Designator Package Quantity Designation Manuf. Part Digikey Ref.
U4 SOT-23-5 1 LDO Exar SPX5205M5-L-3-3 1016-1251-ND
L1 0805 1 SMT jumper Stackpole RMCF0805ZT0R00 RMCF0805ZT0R00CT-ND
C11,C12 0805 2 4.7u, >=16V Samsung CL21A475KOFNNNE 1276-1065-1-ND
D3 SOD-523 1 Schottky Diode ON RB521S30T1G RB521S30T1GOSCT-ND
  • Alternative regulator: Micrel MIC5205
  • D3 is optional for VRAW/VUSB co-existance (and VRAW > VUSB)

LiPo battery charger

Designator Package Quantity Designation Manuf. Part Digikey Ref.
U2 SOT-23-5 1 MCP73831T LiPo charger Microchip MCP73831T-2ACI/OT MCP73831T-2ACI/OTCT-ND
C7 0805 1 4.7u, >=16V Samsung CL21A475KOFNNNE 1276-1065-1-ND
R4 0603 1 20k Samsung RC1608J203CS 1276-5093-1-ND
D2 SOD-523 1 Schottky Diode ON RB521S30T1G RB521S30T1GOSCT-ND

External Flash storage

Designator Package Quantity Designation Manuf. Part Digikey Ref.
U3 8-SOIC 1 SPI Flash 8MBit Winbond W25Q80BVSNIG W25Q80BVSNIG-ND
C10 SM0603_Capa 1 100n >=6.3V Samsung CL10B104KO8NNNC 1276-1005-1-ND
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