Low Cost Variant

The low cost variant is a variant with different and cheap components. It does not fulfill the requirements 100% but still is low power.

Schematics

Top View

Charging Module

Charger IO

RTC cut-off

Regulator

Battery and Protection

MCU

Bill of Main IC Components

Bill Of Materials

Reference

Quantity

Value

Datasheet

Footprint

LCSC

U1

1

FS312F-G

https://www.ic-fortune.com/upload/Download/FS312F-G-DS-12_EN.pdf

Package_TO_SOT_SMD:SOT-23-6_Handsoldering

C82736

U10

1

FP6291LR

www.feeling-tech.com.tw/km-master/ezcatfiles/cust/img/img/24/fp6291v064.pdf

Package_TO_SOT_SMD:SOT-23-6_Handsoldering

C18701

U11 U12

2

ME6210A33P

https://datasheet.lcsc.com/szlcsc/1810201611_MICRONE-Nanjing-Micro-One-Elec-ME6210A33PG_C85233.pdf

Package_TO_SOT_SMD:SOT-89-3_Handsoldering

C85233

U13

1

ESP32-WROOM32

https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32_datasheet_en.pdf

RF_Module:ESP32-WROOM-32

C82899

U2

1

FS8205A

https://www.ic-fortune.com/upload/Download/FS8205A-DS-12_EN.pdf

Package_SO:TSSOP-8_4.4x3mm_P0.65mm

C16052

U3

1

LC709203FQH

https://www.onsemi.com/pub/Collateral/LC709203F-D.PDF

Package_DFN_QFN:WDFN-8-1EP_4x3mm_P0.65mm_EP2.4x1.8mm

C152311

U4

1

TP4056

https://dlnmh9ip6v2uc.cloudfront.net/datasheets/Prototyping/TP4056.pdf

Package_SO:SOP-8_3.9x4.9mm_P1.27mm

C16581

U5

1

CH340G

https://www.mpja.com/download/35227cpdata.pdf

Package_SO:SOP-16_4.55x10.3mm_P1.27mm

C14267

U6

1

AMS1117-3.3

http://www.advanced-monolithic.com/pdf/ds1117.pdf

Package_TO_SOT_SMD:SOT-223-3_TabPin2

C6186

U7

1

PCF8563T

https://www.nxp.com/docs/en/data-sheet/PCF8563.pdf

Package_SO:SOIC-8_3.9x4.9mm_P1.27mm

C7440

U8

1

XC6206P332MR

https://www.torexsemi.com/file/xc6206/XC6206.pdf

Package_TO_SOT_SMD:SOT-23_Handsoldering

C5446

U9

1

TCA6408A

https://www.ti.com/lit/ds/symlink/tca6408a.pdf?ts=1602171918658&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTCA6408A

Package_SO:TSSOP-16_4.4x5mm_P0.65mm

C206177

Y1

1

12MHZ

https://datasheet.lcsc.com/szlcsc/Yangxing-Tech-X322512MSB4SI_C9002.pdf

Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm_HandSoldering

C9002

Y2

1

32.768KHz

1901081604_Seiko-Epson-Q13FC1350000400_C32346.pdf

Crystal:Crystal_SMD_3215-2Pin_3.2x1.5mm

C32346

Full Bill of Materials

Bill Of Materials

Reference

Quantity

Value

Datasheet

Footprint

LCSC

C1 C2 C8 C9 C14 C15 C19 C20

8

0.1µF

~

Capacitor_SMD:C_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C14858

C3 C5 C10 C11 C12 C13 C21

7

1µF

~

Capacitor_SMD:C_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C15849

C4 C16 C17 C18

4

10µF

~

Capacitor_SMD:C_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C19702

C6 C7

2

22pF

~

Capacitor_SMD:C_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C1653

D1 D2

2

LED

~

LED_SMD:LED_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C2286

D3

1

SM4007

http://cdn-reichelt.de/documents/datenblatt/A400/SMD1N400%23DIO.pdf

Diode_SMD:D_MELF

C64898

D4

1

D_Schottky

https://datasheet.lcsc.com/szlcsc/1903051003_MDD-Jiangsu-Yutai-Elec-SS34_C8678.pdf

Diode_SMD:D_SMA_Handsoldering

C8678

J1

1

Battery connector

https://datasheet.lcsc.com/szlcsc/1811051822_JST-Sales-America-S2B-XH-A-LF-SN_C157931.pdf

Connector_JST:JST_EH_S2B-EH_1x02_P2.50mm_Horizontal

C157931

J2

1

Thermistor

https://datasheet.lcsc.com/szlcsc/TDK-NTCG163JF103FT1_C76589.pdf

Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C76589

J3

1

USB_C_Receptacle_USB2.0

https://www.usb.org/sites/default/files/documents/usb_type-c.zip

J4

1

Solar in

https://datasheet.lcsc.com/szlcsc/1811051822_JST-Sales-America-S2B-XH-A-LF-SN_C157931.pdf

Connector_JST:JST_EH_S2B-EH_1x02_P2.50mm_Horizontal

C157931

J5 J6

2

main pin header

~

Connector_PinHeader_2.54mm:PinHeader_1x16_P2.54mm_Vertical

J7

1

IO expander pins

~

Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical

JP1

1

CHRG_Jumper

~

Jumper:SolderJumper-3_P1.3mm_Open_Pad1.0x1.5mm

JP2

1

INT override

~

Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm

JP3

1

MCULDO_override

~

Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm

L1

1

3.3u

~

Inductor_SMD:L_0805_2012Metric_Pad1.15x1.40mm_HandSolder

C51725

Q1 Q2 Q7

3

2N7002

https://www.fairchildsemi.com/datasheets/2N/2N7002.pdf

Package_TO_SOT_SMD:SOT-23

C8545

Q3 Q4

2

S8050

http://www.unisonic.com.tw/datasheet/S8050.pdf

Package_TO_SOT_SMD:SOT-23_Handsoldering

C111272

Q5 Q6

2

AO3401A

http://www.aosmd.com/pdfs/datasheet/AO3401A.pdf

Package_TO_SOT_SMD:SOT-23_Handsoldering

C347476

R1 R10 R18

3

1k

~

Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C21190

R15 R17

2

22k

~

Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C17560

R19 R20

2

5.1k

~

Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C23186

R2

1

100

~

Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C22775

R3 R8 R9 R11 R12

5

10k

~

Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C25804

R4 R5

2

1.8k

~

Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C4177

R6 R13 R14 R16

4

180k

~

Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C22827

R7

1

1M

~

Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder

C22935

U1

1

FS312F-G

https://www.ic-fortune.com/upload/Download/FS312F-G-DS-12_EN.pdf

Package_TO_SOT_SMD:SOT-23-6_Handsoldering

C82736

U10

1

FP6291LR

www.feeling-tech.com.tw/km-master/ezcatfiles/cust/img/img/24/fp6291v064.pdf

Package_TO_SOT_SMD:SOT-23-6_Handsoldering

C18701

U11 U12

2

ME6210A33P

https://datasheet.lcsc.com/szlcsc/1810201611_MICRONE-Nanjing-Micro-One-Elec-ME6210A33PG_C85233.pdf

Package_TO_SOT_SMD:SOT-89-3_Handsoldering

C85233

U13

1

ESP32-WROOM32

https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32_datasheet_en.pdf

RF_Module:ESP32-WROOM-32

C82899

U2

1

FS8205A

https://www.ic-fortune.com/upload/Download/FS8205A-DS-12_EN.pdf

Package_SO:TSSOP-8_4.4x3mm_P0.65mm

C16052

U3

1

LC709203FQH

https://www.onsemi.com/pub/Collateral/LC709203F-D.PDF

Package_DFN_QFN:WDFN-8-1EP_4x3mm_P0.65mm_EP2.4x1.8mm

C152311

U4

1

TP4056

https://dlnmh9ip6v2uc.cloudfront.net/datasheets/Prototyping/TP4056.pdf

Package_SO:SOP-8_3.9x4.9mm_P1.27mm

C16581

U5

1

CH340G

https://www.mpja.com/download/35227cpdata.pdf

Package_SO:SOP-16_4.55x10.3mm_P1.27mm

C14267

U6

1

AMS1117-3.3

http://www.advanced-monolithic.com/pdf/ds1117.pdf

Package_TO_SOT_SMD:SOT-223-3_TabPin2

C6186

U7

1

PCF8563T

https://www.nxp.com/docs/en/data-sheet/PCF8563.pdf

Package_SO:SOIC-8_3.9x4.9mm_P1.27mm

C7440

U8

1

XC6206P332MR

https://www.torexsemi.com/file/xc6206/XC6206.pdf

Package_TO_SOT_SMD:SOT-23_Handsoldering

C5446

U9

1

TCA6408A

https://www.ti.com/lit/ds/symlink/tca6408a.pdf?ts=1602171918658&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTCA6408A

Package_SO:TSSOP-16_4.4x5mm_P0.65mm

C206177

Y1

1

12MHZ

https://datasheet.lcsc.com/szlcsc/Yangxing-Tech-X322512MSB4SI_C9002.pdf

Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm_HandSoldering

C9002

Y2

1

32.768KHz

1901081604_Seiko-Epson-Q13FC1350000400_C32346.pdf

Crystal:Crystal_SMD_3215-2Pin_3.2x1.5mm

C32346