MDBTMicro

MDBTMicro-50Q is an alternative board to nRFMicro/Pro Micro.

It has USB Type-C and LiPo charger, uses Raytac MDBT50Q-x1MV2 nRF52840 module (or MDBT50Q-x512K nRF52833 module) instead of E73-2G4M08S1.

Go to Releases for schematic and Gerber files.

A part of ErgoSNM keyboard project.
EDA: KiCad

PCB

Front	Back	Layers

BOM

Designator	Value	Footprint
C1,C2	1uF	0603 (1608 Metric)
C3,C4	12pF	0603 (1608 Metric)
R1	100k	0603 (1608 Metric)
R2,R4	1k	0603 (1608 Metric)
R3	Rprog	0603 (1608 Metric)
R5	1k	0402 (1005 Metric)
R6	820k	0603 (1608 Metric)
R7,R8	2M	0603 (1608 Metric)
R9,R10	5.1k	0603 (1608 Metric)
D1	1N5819	SOD-323F
J2	USB_C_Receptacle_USB2.0	918-418K2024S40000
LD1	Red	0603 (1608 Metric)
LD2	Blue	0603 (1608 Metric)
LD3	Green	0402 (1005 Metric)
Q1,Q2	AO3407	Package_TO_SOT_SMD:SOT-23
U1	XC6220B331MR-G	SOT-23-5
U2	MDBT50Q-x1MV2	MDBT50Q
U3	TP4057	SOT-23-6
X1	32.768kHz	2Pin 3.2x1.5mm

• Please note that the footprint of R5 and LD3 is 0402.
• R2, R3, U3 and LD1 are not necessary if LiPo charger is not required.
• R6 and R7 are not necessary if LiPo battery monitor is not required.
• Adjust the LiPo charging current with the value of R3.
  • 20 kΩ: 50 mA
  • 10 kΩ: 100 mA
  • 5 kΩ: 200 mA
  • 4 kΩ: 250 mA
  • 3 kΩ: 300 mA
  • 2 kΩ: 400 mA
  • 1.6 kΩ: 500 mA
• XC6220B331MR-G can be replaced by AP2112K-3.3.
• MDBT50Q module includes MDBT50Q-1MV2/P1MV2/U1MV2 (nRF52840-based), or MDBT50Q-512K/P512K/U512K (nRF52833-based).

There is not designator silkscreen on PCB, please use your browser to open the ibom.html file (placed in release page) to refer to the placement of the parts, it is generated by Interactive HTML BOM plugin.

Pinout

MDBTMicro-50Q 1.4	nRFMicro 1.4	Pro Micro	<-->	Pro Micro	nRFMicro 1.4	MDBTMicro-50Q 1.4
GND	GND	--		--	VBAT	VBAT
P0.06	P0.06	D1/Tx		RAW	VBAT	VBUS (USB 5V)
P0.08	P0.08	D0/Rx		GND	GND	GND
GND	GND	GND		RST	P0.18/RESET	P0.18/RESET
GND	GND	GND		VCC	VDD & VDDH	VDD & VDDH
P0.15	P0.15	D2		A3	P0.30	P0.30
P0.17	P0.17	D3		A2	P0.31	P0.31
P0.20	P0.20	D4		A1	P0.29	P0.29
P0.13	P0.13	D5		A0	P0.02	P0.02
P0.24	P0.24	D6		D15	P1.13	P1.13 (P1.05)
P0.09	P0.09	D7		D14	P0.03	P0.03
P0.10	P0.10	D8		D16	P0.28	P0.28
P1.06	P1.06	D9		D10	P1.11	P1.11 (P1.04)
P1.10 (P0.25)	P1.10	--	LED Pin
P0.04	P0.04	--	Battery Pin
P1.09	P1.09	--	Power Pin
P1.12 (P0.23)	--	--	TP1
P1.14 (P1.03)	--	--	TP2
P1.15 (P0.19)	--	--	TP3
P0.05	--	--	TP4
P0.07	--	--	TP5
P0.11	--	--	TP6
P0.12	--	--	TP7

Italics in brackets for MDBT50Q-x512K (nRF52833) pins, otherwise MDBT50Q-x1MV2 (nRF52840).
Almost the same as nRFMicro 1.4

Jumper Config

• JP1
  • nRF52840: Open
  • nRF52833: Close

Board Characteristics

• Copper layer count: 2
• Board overall dimensions: 33.02 mm x 17.78 mm (1.3 x 0.7 inch)
• Min track/spacing: 0.127 mm / 0.127 mm
• Min hole diameter: 0.3 mm

Disclaimer

These files without warranty of any kind, use at your own risk, it is recommended to check yourself before manufacture.

For the full statement, please see LICENSE.