2 layers57 × 55.2 mm
LogicAnalyzer
gusmanb/logicanalyzer
24 channel, 100Msps logic analyzer hardware and software
10 parts5.1kGPL-3.0
2 layers28.9 × 13.4 mm
LT3080 adjustable LDO KiCad PCB design
- Size
- 28.9 × 13.4 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 10
- Nets
- 6
- Pads
- 32
- Tracks, vias
- 37, 4
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 16 May 2026
- Updated
- 16 May 2026
Overview
LDO is an open-source printed circuit board by macnamtran, from the macnamtran/LDO repository on GitHub. It is a 2-layer board of 28.9 × 13.4 mm with 10 parts on 6 nets, routed with 37 tracks and 4 vias.
Its parts include 4 capacitors, 2 resistors, 2 connectors and 1 IC.
README
README.mdLT3080 Adjustable LDO Board
1. Project Overview
Schematic
PCB Layout
3D View
DRC Result
This project is a KiCad PCB design for an adjustable low-dropout linear regulator board using the LT3080xDD. The board takes a DC input voltage and produces an adjustable regulated output voltage.
The purpose of this design is to understand:
- how an LDO regulator is connected
- how the LT3080 output voltage is set
- how external components are selected from the datasheet
- how PCB layout choices such as trace width, capacitor placement, and ground planes affect the design
2. Design Target
| Parameter | Value |
|---|---|
| Regulator IC | LT3080xDD |
| PCB tool | KiCad 9 |
| Input voltage | VIN, nominal 1-5 V |
| Output voltage | Adjustable |
| Target output current | Approximately 0.3 A to 0.5 A |
| PCB type | 2-layer PCB |
| Main ground strategy | Bottom-layer GND plane |
3. LT3080 Pin Connection Summary
The LT3080xDD package has multiple pins connected to the same electrical nets.
| LT3080 Pin | Function | PCB Connection |
|---|---|---|
| Pins 1, 2, 3 | OUT | Connected to VOUT |
| Pin 4 | SET | Connected to R1/RV1 voltage-setting network |
| Pin 5 | VCONTROL | Connected to VIN |
| Pin 6 | NC | Not connected |
| Pins 7, 8 | IN | Connected to VIN |
| Pad 9 | OUT exposed pad | Connected to VOUT, not GND |
Important layout note: the exposed pad, pad 9, is VOUT, not ground. It should connect to the VOUT copper area and should not be connected to the GND plane.
4. Output Voltage Setting
The LT3080 uses a SET pin current to define the output voltage. According to the datasheet, the SET pin current is approximately:
5. Components choice and values
From the datasheet:
a. Stable with 2.2uF ceramic output capacitor, ESR <= 0.5 OHM ==> Connect VIN and VOUT with 2 capacitor: 10uF for stability requirement, 100nF for extra bypassing for fast signal
b. VOUT = RSET * 10uA, VOUT = [1V, 5V] => RSET = [100kOHM, 500kOHM] => RSET = 100kOHM, RV1 = 390kOHM
c. Min load current = 0.5mA R2_max = VOUT_min/ILoad_min=1V/0.5mA = 2kOHM R2_min = VOUT_max/Iwaste_max = 5V/5mA = 1kOHM ==> Pick R2 = 1kOHM
6. Route Width Choice:
Basic rules used in this PCB: - high current path -> wider trace - low current signal/control path -> thinner trace - ground return path -> copper plane
For this LT3080 LDO board, the important current paths are: VIN path: J1 VIN -> input capacitors -> LT3080 IN/VCONTROL
VOUT path: LT3080 OUT/pad 9 -> output capacitors/R2 -> J2 VOUT
GND path: load/capacitor-return current -> GND plane
Route width summary: - VIN/VOUT main trace: 1.0mm - short necks into LT3080 small pins/pin connections: 0.25mm
Parts
10| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | Conn_01x02_Pin | TerminalBlock:TerminalBlock_bornier-2_P5.08mm | J1, J2 |
| 1 | 10 uF | Capacitor_SMD:C_0805_2012Metric | C1 |
| 1 | 100 nF | Capacitor_SMD:C_0805_2012Metric | C2 |
| 1 | 100k | Resistor_SMD:R_0805_2012Metric | R1 |
| 1 | 100nF | Capacitor_SMD:C_0805_2012Metric | C4 |
| 1 | 10uF | Capacitor_SMD:C_0805_2012Metric | C3 |
| 1 | 3.3k | Resistor_SMD:R_0805_2012Metric | R2 |
| 1 | LT3080xDD | Package_DFN_QFN:DFN-8-1EP_3x3mm_P0.5mm_EP1.66x2.38mm | U1 |
| 1 | R_Potentiometer | Potentiometer_THT:Potentiometer_Bourns_3296W_Vertical | RV1 |
Questions
How big is the LDO PCB?
It measures 28.9 × 13.4 mm and has 2 copper layers, 1.6 mm thick.
What parts does the LDO use?
10 parts. 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 LDO KiCad files?
From the macnamtran/LDO repository on GitHub, at the commit this page was made from: the board is LDO.kicad_pcb and its schematic LDO.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the LDO design in my own project?
Its repository states no licence, so its author keeps all rights: ask macnamtran before reusing the design.
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