Project-LabAnalogDesign2

The goal of this lab was to design a 5 - 9V to 3,3V (500 mA min) buck converter from the ground up. We had to start from a given chip (RT8259GE) and create the rest ourselves.

Careful layout considerations were taken to lead to an optimal design. The 0Ω resistor is not on the schematic but only on the board layout. It's footprint was used to jump over the feedback track so everything is on the top layer. A via to GND is placed around it as well for redundancy.

• JP1 can be used to disable the buck converter.
• JP2 can be used to bypass the sense resistor R3 (measures the diode current).
• A lot of test points (TPx) are given to be able to measure different voltages.
• C4 and C5 are footprints for extra capacitors if the signals have too much ripple.

• VIN: 4,5 - 24 V
• VOUT: 3,3 V @ 1,2 A max

• Click here to go to the schematic.
• Click here to go to the report (Dutch).

   

BOM

Component	Value	Footprint	Other	Ordering
U1	RT8259GE	SOT-23-6	Richtek
C1, C4	10 µF	1206	(X7R), 50V, 10%	Mouser.be
C2, C5	22 µF	1206	X7R, 10V, 10%	Mouser.be
C3	10 nF = 0,01 µF	0805	X7R, 50V, 10%	Mouser.be
D1	If = 2A Vr = 40V Vf = 0,43V	SMA/SMB		Mouser.be
L1	4,7 µH	NR8040	Taiyo Yuden	Mouser.be
R1	62 kΩ	0805	0,5%	Mouser.be
R2	19,6 kΩ	0805	0,5%	Mouser.be
R3	0,1 Ω = 100 mΩ	1206	1%	Mouser.be
0Ω	0 Ω	1206		Mouser.be
J1, J2	PTSA_1,5/_2-3,5-Z_BK	Pitch: 3,5 mm	2 contacts, 250V 2A	Mouser.be

WARNING: The pinout of J1 and J2 is reversed due to a footprint error (wrong top/bottom view). The Phoenix Contact connectors can however be manually separated and put back together in a way that they do fit on the board.