Logic Probe 16 v2.2: A 16-Channel Logic Analyzer Probe for the Rigol MSO5000
16-channel logic analyzer probe for Rigol MSO5000 series oscilloscopes. Based on the open-source S. Petrukhin design. Assembled, tested, and enclosed by SAM Controllers.
What This Is
The Logic Probe 16 v2.2 converts 16 single-ended digital signals into LVDS pairs that your Rigol MSO5000 can read through its 50-pin logic analyzer port. It is powered entirely by the scope. There is nothing to configure. Plug it in, connect your signals, and the scope sees 16 digital channels.
Headline numbers: 16 channels (D0 to D15), 5 V maximum input, approximately 1.4 V fixed threshold, and no external power.
Signal path, per channel
Your signal (0 to 5 V digital) passes through a series input resistor (R0 to R15) into an SN65LVDS1 TTL/CMOS-to-LVDS driver, then through a 100 Ω termination (R100 to R115) and out over the 50-pin IDC connector as an LVDS pair.
The SN65LVDS1 has a fixed switching threshold of approximately 1.4 V at a 3.3 V supply. Signals above roughly 1.4 V read as logic high, below as logic low. Per the TI datasheet, the input accepts voltages up to 5 V regardless of supply voltage.
How It Works
1. Connect to the scope
Plug a 50-pin IDC ribbon cable from the probe’s P3 connector into your MSO5000’s logic analyzer port. The probe draws power from the scope’s +4 V rail. The on-board LED confirms power.
2. Attach probe wires
Connect jumper wires or grabber clips from P1 (D0 to D7) and P2 (D8 to D15) to your circuit. Connect a ground wire between the probe and your circuit. LVDS requires a common ground reference.
3. Capture and decode
Press Logic Analyzer on the scope. All 16 channels appear as D0 to D15. Add protocol decoders (SPI, I2C, UART, parallel bus) and trigger on any digital channel.
Specifications
- Channels: 16 (D0 to D15), single-ended
- Input connectors: P1 (D0 to D7) and P2 (D8 to D15), 2×8 pin headers, 2.54 mm pitch
- Input voltage: 0 to 5 V (per TI SN65LVDS1 datasheet)
- Switching threshold: approximately 1.4 V fixed, TTL-level, not adjustable by the scope
- Driver IC: TI SN65LVDS1 ×16, SOT-23-5
- LVDS termination: 100 Ω per channel (R100 to R115)
- Input protection: series resistors R0 to R15
- Voltage regulator: ON Semi MC33375ST-3.3T3G, SOT-223, 260 mV typical dropout
- Power source: +4 V from the scope via the 50-pin connector
- Scope connector: P3, 50-pin IDC header, 2.54 mm pitch
- PCB: 2-layer, approximately 60×80 mm
- Mounting: 4× M3 holes
- Indicator: power LED
- Passives: 0805 throughout
- Design origin: S. Petrukhin, open source (EasyEDA), October 2020
3.3 V and 5 V logic
The approximately 1.4 V threshold sits comfortably between the noise floor and the logic-high level of 3.3 V and 5 V circuits. Arduino, ESP32, STM32, Raspberry Pi GPIO, PIC, AVR, and classic 74HC/74HCT all produce clean captures.
Protocol decoding
The scope’s built-in decoders work on the digital channels: SPI, I2C, UART, RS-232 (with a transceiver), and parallel bus. You can trigger on protocol events and correlate digital captures with analog channels on the same timebase.
Documented and repairable
Every component is identified: 16× TI SN65LVDS1 (SOT-23-5), MC33375 LDO (SOT-223), 100 Ω termination resistors, 0805 passives. Full open-source schematic. If a channel fails, you can isolate and replace a single driver IC.
Proper LVDS termination
Each channel has a 100 Ω parallel termination resistor. The MSO5000 provides 33 Ω series resistance internally but does not terminate the LVDS pairs. Without the on-probe 100 Ω termination, you get signal reflections and unreliable captures.
What It Does Not Do
No adjustable threshold. The SN65LVDS1 is a CMOS/TTL-to-LVDS driver with a fixed threshold near 1.4 V. The scope’s threshold setting in the Logic Analyzer menu has no effect on this probe. For 1.8 V logic, slow-slew signals, or signals with DC offsets near 1.4 V, this threshold may not be in the right place. The Rigol PLA2216 uses LMH7322 comparators that accept the scope’s threshold setting.
No differential inputs. All 16 channels are single-ended and ground-referenced. To capture differential buses (CAN, RS-485, differential I2C, LVDS lines), you need an external transceiver to convert to a single-ended signal first.
No overvoltage beyond 5 V. The SN65LVDS1 input accepts up to 5 V per TI’s datasheet. The series input resistors provide some additional current limiting, but signals above 5 V or below 0 V, such as RS-232 levels or motor drive outputs, will damage the driver ICs.
2-layer PCB, traces not length-matched. Functional for all standard digital protocols. At very high edge rates (under 5 ns rise time), you may see small differences in channel-to-channel timing. This does not affect protocol decoding or triggering for SPI, I2C, UART, or parallel buses at typical speeds.
Comparison: every option on the market
There are four distinct approaches to getting a 16-channel logic probe for the MSO5000. Each uses different ICs and has different trade-offs.
| Specification | Rigol PLA2216 | eBay clones (v3) | Climbers.net v3.1 (DIY) | Logic Probe 16 v2.2 |
|---|---|---|---|---|
| Sold as | Assembled | Assembled | DIY only (KiCad files) | PCB, assembled, or kit |
| Signal IC | LMH7322 dual comparator (×8) | SN65LVDS391 quad driver (×4) | SN65LVDS391 quad driver (×4) | SN65LVDS1 single driver (×16) |
| IC type | Comparator, adjustable reference | LVDS driver, fixed threshold | LVDS driver, fixed threshold | LVDS driver, fixed threshold |
| Threshold | Adjustable via scope UI | Fixed, approx 1.4 V TTL | Fixed, approx 1.4 V TTL | Fixed, approx 1.4 V TTL |
| Max input | ±40 V | 5 V | 5 V | 5 V |
| Termination | 100 Ω | 100 Ω | 100 Ω | 100 Ω per channel |
| LDO regulator | Custom | Unknown | TLV743P | MC33375ST-3.3T3G |
| PCB | 4-layer | 2-layer | 2-layer, 80×60 mm | 2-layer, approx 60×80 mm |
| Input protection | Yes | Unknown | Basic | Series resistors R0 to R15 |
| Schematic | Proprietary | Not provided | Open source (KiCad) | Open source (EasyEDA and KiCad) |
| Enclosure | Injection molded | Varies | None | 3D-printed case |
| Ships from | Distributor | China, 2 to 4 weeks | Self-build | USA, 2 to 3 days |
| Design origin | Rigol, proprietary | Based on Peter Lampe v3 | Peter Lampe v3.1 | S. Petrukhin v2.2 |
All three fixed-threshold designs (eBay clones, Climbers.net, and Logic Probe 16) produce the same result on your scope for 3.3 V and 5 V logic. The difference is IC topology: quad drivers mean 4 ICs and fewer solder joints, single drivers mean 16 ICs and per-channel repair. The Rigol PLA2216 is the only option with an adjustable threshold, which matters for 1.8 V logic, mixed-voltage systems, or signals with large DC offsets. For standard embedded work (Arduino, STM32, ESP32, FPGA, Raspberry Pi), any of these probes will capture and decode your signals identically.
Scope Compatibility
- MSO5072 / MSO5074: confirmed compatible
- MSO5102 / MSO5104: confirmed compatible
- MSO5204 / MSO5354: confirmed compatible
- DHO914 / DHO924: same 50-pin connector. Community reports suggest compatibility but we have not tested it. Ask us before ordering.
- MSO1000Z series: not compatible. It uses a different probe (RPL1116) with a different pinout.
- Other scopes: this probe only works with scopes that have a 50-pin MSO5000-style logic analyzer port.
What Is Included
Four configurations are available. For current pricing and availability see the Logic Probe 16 v2.2 product page.
Bare PCB
Unpopulated 2-layer board. BOM with part numbers for LCSC, Mouser, and DigiKey. Links to EasyEDA and KiCad schematics. All passives are 0805. The SN65LVDS1 is SOT-23-5.
Assembled board
Fully soldered board. Every channel tested for correct LVDS output before shipping. No enclosure or accessories.
Complete kit
Enclosed probe, 50-pin IDC ribbon cable, and 16 mini grabber clips for connecting to your circuit.
About this design
The Logic Probe 16 v2.2 is based on the open-source “Digital probe MSO5000 CMOS/TTL v2.2” by S. Petrukhin (EasyEDA/OSHWLab project), published October 2020. The design also has a community thread on EEVblog with discussion of the design decisions, alternative approaches, and user build reports. A KiCad conversion with improved trace routing is also available from hydrabus.
Component details
U0 to U15: 16× TI SN65LVDS1 single LVDS drivers
U16: ON Semi MC33375ST-3.3T3G LDO, 4 V to 3.3 V, 260 mV dropout, 300 mA
R0 to R15: series input resistors for protection
R100 to R115: 100 Ω LVDS termination
R16: probe detect pull-down, so the scope sees the probe is connected
R17: LED current limiter
C1 to C5, C9, C10: bypass and decoupling capacitors
P1, P2: 2×8 pin input headers
P3: 50-pin IDC connector
Frequently Asked Questions
Does the scope’s threshold setting affect this probe?
No. The MSO5000 sends a reference voltage on pins 36 and 37 of the 50-pin connector for probes that use comparators, such as the Rigol PLA2216. This probe uses SN65LVDS1 drivers, which have a fixed TTL-level threshold near 1.4 V and do not read the scope’s reference voltage. Changing the threshold in the Logic Analyzer menu has no effect.
Will this work with 1.8 V logic?
Unreliably. A 1.8 V logic-high signal is only 0.4 V above the 1.4 V threshold, which leaves very little noise margin. You may get captures that work on a clean bench but fail with any noise. For 1.8 V logic you need a probe with an adjustable threshold, such as the Rigol PLA2216.
Can I decode CAN bus or RS-485?
Not directly. CAN and RS-485 are differential buses and this probe has single-ended inputs. You would need an external transceiver IC, for example MCP2551 for CAN or MAX485 for RS-485, to convert the differential signal to single-ended, then connect the transceiver output to the probe.
Is this probe identical to the Rigol PLA2216?
No. Different ICs, different circuit topology, different PCB design. The PLA2216 uses LMH7322 comparators, 8 ICs, adjustable threshold, ±40 V input range, on a 4-layer PCB. This probe uses SN65LVDS1 drivers, 16 ICs, fixed threshold, 0 to 5 V input, on a 2-layer PCB. For 3.3 V and 5 V signals they produce the same result on your scope screen.
Why not just buy the cheap one on eBay?
The eBay probes work for many people. The difference: their ICs are not documented, with no datasheet and no schematic, termination is unverified, support is nonexistent, and shipping takes 2 to 4 weeks from China. This probe uses documented TI parts with a published open-source schematic, ships from the US in a few days, and you can email us if something does not work.
How is this different from a Saleae or other USB logic analyzer?
USB logic analyzers stream data to a PC. This probe connects to your oscilloscope’s built-in logic analyzer, so you see analog and digital channels on the same timebase, with the same trigger system, on one screen. If you already have a Rigol MSO5000, this uses the 16-channel logic analyzer hardware that is already built into the scope.
What does the bare PCB include?
The unpopulated board, a BOM listing all component values with part numbers for LCSC, Mouser, and DigiKey, and links to the full schematic in EasyEDA and KiCad formats. All resistors and capacitors are 0805 and solderable with a standard iron and flux. The SN65LVDS1 in SOT-23-5 requires a fine tip or hot air.
Does it need external power?
No. The probe draws power from the +4 V rail that the MSO5000 provides through the 50-pin connector. The on-board MC33375 LDO regulates this down to 3.3 V. When the LED lights up, the probe is powered and ready.
Get 16 digital channels on your MSO5000
Your scope already has the hardware. It just needs a probe. See the Logic Probe 16 v2.2, or read the multi-protocol FPGA test walkthrough.