2 layers101.6 × 53.3 mm
4 layers55 × 50 mm
Interface2
lowobservable/coax53Connect to IBM 3270 hardware
- Size
- 55 × 50 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 68
- Nets
- 56
- Pads
- 336
- Tracks, vias
- 760, 136
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 27 Jun 2019
- Updated
- 8 Feb 2026
Overview
Interface2 is an open-source printed circuit board by lowobservable, from the lowobservable/coax repository on GitHub, published under the ISC licence. It is a 4-layer board of 55 × 50 mm with 68 parts on 56 nets, routed with 760 tracks and 136 vias.
It is built around the ICE40UP5K-SG48I, STM32L443CCU6 and DS34LV87TM, with the DS34LV86TM, MIC5365-1.2YC5-TR and MIC5504-3.3YM5 among its other parts. Its parts include 25 capacitors, 16 resistors, 7 ICs, 4 diodes and 3 connectors. It belongs with the STM32 and FPGA and CPLD boards of this library.
Main components
7
ICE40UP5K-SG48I
QFN-48-EP(7x7)-40℃~+100℃ 1.14V~1.26V 1171456bit 39 5280 660 iCE40 UltraPlus QFN-48-EP(7x7) Programmable Logic Device (CPLDs/FPGAs) ROHSLatticeProgrammable Logic Device (CPLDs/FPGAs)
STM32L443CCU6
UFQFPN-48(7x7)-40℃~+85℃ 1.71V~3.6V 12bit 12bit 256KB 32 Bit 38 64KB 80MHz ARM Cortex-M4 Built-in FLASH UFQFPN-48(7x7) Microcontrollers (MCU/MPU/SOC) ROHSSTMicroelectronicsMicrocontrollers (MCU/MPU/SOC)
DS34LV87TM
SOIC-16-40℃~+85℃ 0 100uA 3V~3.6V 4 Driver SOIC-16 RS-485 / RS-422 ICs ROHSTexas InstrumentsRS-485 / RS-422 ICsDS34LV86TM
SOIC-16-40℃~+85℃ 0 3V~3.6V 4 Receiver SOIC-16 RS-485 / RS-422 ICs ROHSTexas InstrumentsRS-485 / RS-422 ICs
MIC5365-1.2YC5-TR
SC-70-5-40℃~+125℃@(Tj) 1 1.2V 150mA 155mV@(150mA) 200uVrms 29uA 5.5V 65dB@(10kHz) Fixed Over Current Protection、Over Temperature Protection、Enable Positive SC-70-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSMicrochip TechnologyVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
MIC5504-3.3YM5
SOT-23-5-40℃~+125℃@(Tj) 1 120uVrms 15uA 180mV@(300mA) 3.3V 300mA 5.5V 75dB@(1kHz) Fixed Over Temperature Protection、Enable Positive SOT-23-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTECH PUBLICVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
USBLC6-2SC6
SOT-23-60.35pF、0.8pF 100nA 150W@8/20us 15V 2 5V 6A@8/20us 6V ESD SOT-23-6 ESD and Surge Protection (TVS/ESD) ROHSUMWESD And Surge Protection (TVS/ESD)
README
README.mdcoax
Tools for connecting to real IBM 3270 type terminals.
Documentation
- protocol - Protocol documentation
Hardware
- interface1 - Legacy interface using obsolete National Semiconductor DP8340 and DP8341
- interface2 - Modern interface using a Lattice iCE40 FPGA and STM32 microcontroller
Software
- pycoax - Python interface library
See Also
- oec - IBM 3270 terminal controller (a replacement for the IBM 3174)
Parts
68| Qty | Value | Footprint | References |
|---|---|---|---|
| 15 | 0.1uF | Capacitor_SMD:C_0603_1608Metric | C1, C2, C10, C11, C12, C13, C14, C16, C17, C19, C21, C22, C23, C24, C25 |
| 6 | 1uF | Capacitor_SMD:C_0603_1608Metric | C5, C6, C7, C8, C18, C20 |
| 5 | 10k | Resistor_SMD:R_0603_1608Metric | R7, R9, R10, R13, R15 |
| 5 | TestPoint | TestPoint:TestPoint_Pad_D1.0mm | TP3, TP4, TP5, TP6, TP13 |
| 4 | 560 | Resistor_SMD:R_0603_1608Metric | R8, R11, R12, R16 |
| 4 | MountingHole_Pad | MountingHole:MountingHole_2.7mm_M2.5_ISO7380_Pad | H1, H2, H3, H4 |
| 2 | 0.01uF | Capacitor_SMD:C_0603_1608Metric | C3, C4 |
| 2 | 150 | Resistor_SMD:R_0603_1608Metric | R1, R2 |
| 2 | 33 | Resistor_SMD:R_0603_1608Metric | R3, R4 |
| 2 | YEL | LED_SMD:LED_0603_1608Metric | D2, D3 |
| 1 | 100 | Resistor_SMD:R_0603_1608Metric | R14 |
| 1 | 10uF | Capacitor_SMD:C_0603_1608Metric | C15 |
| 1 | 120 | Resistor_SMD:R_0603_1608Metric | R6 |
| 1 | 4.7uF | Capacitor_SMD:C_0603_1608Metric | C9 |
| 1 | 500mA | Fuse:Fuse_1206_3216Metric | F1 |
| 1 | 510 | Resistor_SMD:R_0603_1608Metric | R5 |
| 1 | Conn_Coaxial | Connector_Coaxial:BNC_Amphenol_B6252HB-NPP3G-50_Horizontal | J1 |
| 1 | DS34LV86T | Package_SO:SOIC-16_3.9x9.9mm_P1.27mm | U1 |
| 1 | DS34LV87T | Package_SO:SOIC-16_3.9x9.9mm_P1.27mm | U2 |
| 1 | DSC6001CI2A | library:CDFN3225-4LD-PL-1 | X1 |
| 1 | Ferrite_Bead | Fuse:Fuse_1206_3216Metric | FB1 |
| 1 | GRN | LED_SMD:LED_0603_1608Metric | D1 |
| 1 | ICE40UP5K-SG48I | Package_DFN_QFN:QFN-48-1EP_7x7mm_P0.5mm_EP5.6x5.6mm | U3 |
| 1 | MIC5365-1.2YC5 | Package_TO_SOT_SMD:SOT-353_SC-70-5 | U5 |
| 1 | MIC5504-3.3YM5 | Package_TO_SOT_SMD:SOT-23-5 | U4 |
| 1 | Murata 78602/8JC | library:Murata_786J | T1 |
| 1 | RED | LED_SMD:LED_0603_1608Metric | D4 |
| 1 | STM32L443CCU6 | Package_DFN_QFN:QFN-48-1EP_7x7mm_P0.5mm_EP5.6x5.6mm | U7 |
| 1 | TestPoints | library:TestPoint_Pad_2x12_D1.0mm | J3 |
| 1 | USBLC6-2SC6 | Package_TO_SOT_SMD:SOT-23-6 | U6 |
| 1 | USB_B_Micro | Connector_USB:USB_Micro-B_Amphenol_10103594-0001LF_Horizontal | J2 |
Questions
How big is the Interface2 PCB?
It measures 55 × 50 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Interface2 use?
68 parts, built around the ICE40UP5K-SG48I, STM32L443CCU6, DS34LV87TM and DS34LV86TM. 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 Interface2 KiCad files?
From the lowobservable/coax repository on GitHub, at the commit this page was made from: the board is interface2/pcb/pcb.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the Interface2 design in my own project?
Its repository publishes it under the ISC licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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