2 layers88.9 × 46.4 mm Sync flyback eval, the printed circuit board in 3D

Sync flyback eval

A base platform for PoE peripherals

Size: 88.9 × 46.4 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 97
Nets: 70
Pads: 269
Tracks, vias: 425, 29
Pours: 3
Routed: Yes
KiCad: KiCad 6 (file 20211014)
Created: 20 Jan 2018
Updated: 20 Oct 2026

Overview

Sync flyback eval is an open-source printed circuit board by crawford, from the crawford/PoE repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 88.9 × 46.4 mm with 97 parts on 70 nets, routed with 425 tracks and 29 vias.

It is built around the TCMT1107, TPS23754PWPR and BAV99, with the MMDT3906, PT61017PEL and SIR422DP among its other parts. Its parts include 29 capacitors, 25 resistors, 9 diodes, 3 transistors and 2 ICs.

Main components

README

hardware/sync-flyback-eval/README.md

Synchronous Flyback Converter Evaluation

Test Plan

Core Converter

Populate:

FB1-FB2
R2-R3, R5-R14, R19-R21, R23-R25
RV1-RV4
L1-L2
C1-C12, C15-C17, C22, C24, C26-C28
D1-D2, D6
Q1-Q3A
U2
T1-T2

Tune:

Set RV1 to 22.1 kΩ.
Set RV2 to 69.8 kΩ.
Set RV3 to 69.8 kΩ.
Set RV4 to 115 kΩ.

Test:

Insufficient supply a. Apply 5-volt supply across VDDA (TP10) and VSSA (TP11). b. Measure voltage across R7 and verify that it is 0 V.
24-volt supply a. Apply 470-ohm resistance across +12V (TP8) and GNDD (TP13). b. Apply 24-volt supply across VDDA and VSSA. c. Measure voltage across R8 and verify that it is 255 μV. d. Measure voltage across R7 and verify that it is ~181 μV.
48-volt supply a. Connect 470-ohm resistance across +12V (TP8) and GNDD (TP13). b. Connect 24-volt supply across VDDA and VSSA. c. Measure voltage across R8 and verify that it is 255 μV. d. Measure voltage across R7 and verify that it is ~128 μV.

Power over Ethernet

Populate:

J1
TR1
C13-C14, C18-C21, C25
R1, R15-R18
D3-D5

Test:

Passive PoE a. Connect to passive (24-volt) PoE PS. b. Measure voltage across VDDA and VSSA and verify that it is ~24 V. c. Verify that the yellow LED turns on.
PoE+ a. Connect 470-ohm resistance across +12V and GNDD. b. Connect to PoE+ PS. c. Measure voltage across VDDA and VSSA and verify that is is 37-57 V. d. Verify that the yellow LED turns on.

Parts

Qty	Value	Footprint	References
5	VB	TestPoint:TestPoint_Loop_D1.80mm_Drill1.0mm_Beaded	TP7, TP9, TP15, TP16, TP17
4	0-200k	common:TRIM_3306F-1-204	RV1, RV2, RV3, RV4
4	0u01	Capacitor_SMD:C_0402_1005Metric	C18, C19, C20, C21
4	1u	Capacitor_SMD:C_0402_1005Metric	C9, C11, C16, C27
4	75	Resistor_SMD:R_0402_1005Metric	R15, R16, R17, R18
3	0u1	Capacitor_SMD:C_0402_1005Metric	C1, C5, C14
3	1n	Capacitor_SMD:C_0402_1005Metric	C13, C25, C29
2	0u47	Capacitor_SMD:C_0402_1005Metric	C17, C22
2	10	Resistor_SMD:R_0805_2012Metric	R3, R6
2	10k	Resistor_SMD:R_0402_1005Metric	R14, R25
2	10m	Resistor_SMD:R_0402_1005Metric	R7, R8
2	1k2	Resistor_SMD:R_0402_1005Metric	R1, R4
2	1u	Capacitor_SMD:C_0805_2012Metric	C3, C4
2	330u	Capacitor_SMD:C_Elec_8x10.2	C7, C8
2	BAV99	Package_TO_SOT_SMD:SOT-23	D8, D9
2	D	Diode_SMD:D_SOD-323	D2, D7
2	D_Bridge_+-AA	Diode_SMD:Diode_Bridge_Diotec_ABS	D4, D5
2	Ferrite_Bead_Small	Resistor_SMD:R_1206_3216Metric	FB1, FB2
2	GND	TestPoint:TestPoint_Loop_D1.80mm_Drill1.0mm_Beaded	TP12, TP13
1	0	Resistor_SMD:R_0402_1005Metric	R23
1	0R18	Resistor_SMD:R_0805_2012Metric	R12
1	0u33	common:L_Abracon_ASPI-0630LR	L2
1	121k	Resistor_SMD:R_0402_1005Metric	R22
1	12V	TestPoint:TestPoint_Loop_D1.80mm_Drill1.0mm_Beaded	TP8
1	13k3	Resistor_SMD:R_0402_1005Metric	R21
1	150u	Capacitor_SMD:C_Elec_6.3x7.7	C6
1	1k5	Resistor_SMD:R_0402_1005Metric	R24
1	1n2	Capacitor_SMD:C_0402_1005Metric	C10
1	22u	Capacitor_SMD:C_Elec_5x5.4	C12
1	27n	Capacitor_SMD:C_0402_1005Metric	C26
1	2k	Resistor_SMD:R_0402_1005Metric	R13
1	2k2	Resistor_SMD:R_0402_1005Metric	R19
1	2n2	Capacitor_THT:C_Disc_D10.0mm_W2.5mm_P5.00mm	C15
1	330p	Capacitor_SMD:C_0402_1005Metric	C23
1	39K	Resistor_SMD:R_0805_2012Metric	R2
1	39k7	Resistor_SMD:R_0402_1005Metric	R5
1	3n3	Capacitor_SMD:C_0402_1005Metric	C24
1	3u3	common:L_Abracon_ASPI-0630LR	L1
1	47u	Capacitor_SMD:C_Elec_8x10.2	C2
1	4R7	Resistor_SMD:R_0402_1005Metric	R10
1	62k	Resistor_SMD:R_0402_1005Metric	R9
1	63R4	Resistor_SMD:R_0402_1005Metric	R11
1	6k04	Resistor_SMD:R_0402_1005Metric	R20
1	6n8	Capacitor_SMD:C_0402_1005Metric	C28
1	CS	TestPoint:TestPoint_Pad_1.5x1.5mm	TP6
1	CTL	TestPoint:TestPoint_Pad_1.5x1.5mm	TP4
1	D	Diode_SMD:D_SMB	D1
1	D_Zener	Diode_SMD:D_SMA	D3
1	EARTH	TestPoint:TestPoint_Loop_D1.80mm_Drill1.0mm_Beaded	TP14
1	GAT	TestPoint:TestPoint_Pad_1.5x1.5mm	TP5
1	GAT2	TestPoint:TestPoint_Pad_1.5x1.5mm	TP3
1	MMDT3906	Package_TO_SOT_SMD:SOT-363_SC-70-6	Q3
1	PT61017PEL	common:PT61017PEL	TR1
1	PoE_Transformer	common:WE-PoE+	T1
1	Pulse_Transformer	common:WE-GDTI	T2
1	RJ45_LED_Shielded	common:RJHSE-538X	J1
1	Si7898DP	common:PowerPAK_SO-8_Single	Q2
1	SiR422DP	common:PowerPAK_SO-8_Single	Q1
1	TCMT1107	Package_SO:SOP-4_4.4x2.6mm_P1.27mm	U2
1	TL431DBZ	Package_TO_SOT_SMD:SOT-23	D6
1	TPS23754PWPR	common:TSSOP-20	U1
1	TestPoint	TestPoint:TestPoint_Pad_1.5x1.5mm	TP1
1	VC	TestPoint:TestPoint_Loop_D1.80mm_Drill1.0mm_Beaded	TP2
1	VDDA1	TestPoint:TestPoint_Loop_D1.80mm_Drill1.0mm_Beaded	TP10
1	VSSA1	TestPoint:TestPoint_Loop_D1.80mm_Drill1.0mm_Beaded	TP11

Questions

How big is the Sync flyback eval PCB?

It measures 88.9 × 46.4 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Sync flyback eval use?

97 parts, built around the TCMT1107, TPS23754PWPR, BAV99 and MMDT3906. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Sync flyback eval KiCad files?

From the crawford/PoE repository on GitHub, at the commit this page was made from: the board is hardware/sync-flyback-eval/sync-flyback-eval.kicad_pcb and its schematic hardware/chassis/chassis.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Sync flyback eval design in my own project?

Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/crawford-poe-sync-flyback-eval" title="Sync flyback eval in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/crawford-poe-sync-flyback-eval.jpg" alt="Sync flyback eval" width="1200" height="900">

A picture that opens the board, for a README

[![Sync flyback eval](https://pcbkit.io/embed/boards/crawford-poe-sync-flyback-eval.jpg?size=s)](https://pcbkit.io/boards/crawford-poe-sync-flyback-eval)

Source

Repository: crawford/PoE
Board file: hardware/sync-flyback-eval/sync-flyback-eval.kicad_pcb
Commit: 0c61c99
Licence: GPL-3.0

Similar boards

4 layers120 × 120 mm
Yellow
NabuCasa/yellow
Home Assistant Yellow - hardware for Home Assistant which grows with your needs.
322 parts116
2 layers102.7 × 56.8 mm
RecoveryBoard
psas/lv3.1-recovery
design, analysis, CAD, and testing for the LV3.1 recovery system
158 parts13
4 layers53.3 × 21 mm
Open80017a
ThomHPL/Open80017a
Version 0.2 fixes the footprints. It has not yet been assembled or tested.
52 parts10CERN-OHL-S-2.0
4 layers40 × 55 mm
CopterCat cm4
matveylapin/CopterCat_cm4
Полётный контроллер для стандарта FMU-v6u. Обычно на дронах для программирования устанавливают полётный контроллер, одноплатный компьютер и иногда arduino.
164 parts3Apache-2.0
6 layers91.5 × 91.5 mm
IO SDR 1.1
SunnyYoshimitsu/Reconfigurable-Space-Compute-Cluster
Here will be the repository for an "extremely reconfigurable satellite" aimed toward at competing in NASA Minds and hopefully assist Artemis in its missions.
284 parts3
2 layers50 × 100 mm
OpenWeatherStation MainBoard
VitalSeptfonds/OpenWeatherStation
Open Wheather Station based on STM32
111 parts2MIT
2 layers68.3 × 57.3 mm
2 stage BJT opamp
meekdenzo/capstone

35 parts1
4 layers102.5 × 35 mm
PoE
ndarash93/PoE

106 parts1