UNI-T UDP3303C 3Ch Advanced Series Programmable Linear DC Power Supply
Overview
The UDP3303C is the SCPI-programmable counterpart to the UDP3303A — same 195W three-channel linear hardware, same CH3 logic-rail selector cycling 1.8V / 2.5V / 3.3V / 5V at 3.2A, same ≤1 mVrms ripple — with a back-panel USB-Device port and RS-232 added for full SCPI control. CH1 and CH2 deliver 0–30V at 0–3A; series and parallel modes extend that to 60V or 6A.
Programming accuracy holds inside ≤0.1% + 30 mV on voltage and ≤0.5% + 2 mA on current — fine enough for sleep-mode current characterization on IoT prototypes, battery-charge cut-off testing, and any automated sweep that needs the setpoint to land exactly where you asked it. Five preset storage groups (M1–M5), shutdown memory, OVP / OCP / OTP per channel, and a Digital I/O hardware ON/OFF pin pair round out a programmable supply built for benches that have to behave the same way every time. For 5A per adjustable channel, see the UDP3305C; for the knob-only manual variant, see the UDP3303A.
Key Features
- Three Channels, 195W Total — SCPI Programmable — CH1 and CH2: 0–30V / 0–3A adjustable. CH3: switchable 1.8V / 2.5V / 3.3V / 5V at 3.2A. SCPI control over USB-Device or RS-232.
- USB-Device + RS-232 with SCPI — Back-panel data interfaces for PC connection. Standard accessories include both a USB cable (UT-D14) and RS-232 communication line — pick the bus your test rig already uses.
- Programming Accuracy ≤0.1% + 30 mV — Voltage programming accuracy ≤0.1% + 30 mV; current programming accuracy ≤0.5% + 2 mA. Set value matches output value across the full range.
- CH3 Logic-Rail Selector — Single front-panel button cycles CH3 through 1.8V / 2.5V / 3.3V / 5V at 3.2A. CMOS, microcontroller cores, legacy TTL, USB-class — covered without sacrificing CH1/CH2.
- Linear Topology, ≤1 mVrms Ripple — Clean DC output for low-noise analog work. Load regulation ≤0.01% + 3 mV in CV mode.
- 10 mV / 1 mA Resolution — Four-digit voltage and current display per channel on EBTN LCD.
- Series, Parallel, and Tracking Modes — Combine CH1+CH2 for up to 60V series or 6A parallel from the front panel. SCPI exposes the same modes for automated test integration.
- OVP / OCP / OTP Protection — Configurable per-channel thresholds, plus over-temperature shutdown and keypad lock.
- Five Preset Storage Groups — M1–M5 store full instrument states for fast bench setup. Shutdown memory restores last settings on power-up.
- Front-Panel 5V/2A USB Charging Port (CH4) — Independent 5V/2A USB-A charging output. Charging output only — the data interfaces are USB-Device and RS-232 on the back panel.
- Hardware Output Disable via Digital I/O — Two-pin Digital I/O terminal for emergency cutoff and external interlock circuits.
Detailed Features
CH3 Logic-Rail Selector — One Button, Four Voltages
Most three-channel bench supplies give you two adjustable channels and a fixed 5V rail you'll resent the moment you need 3.3V. The UDP3303C's CH3 cycles between 1.8V, 2.5V, 3.3V, and 5V at 3.2A — covering CMOS logic, modern microcontroller cores, legacy TTL, and USB-class devices — at a single front-panel button press. CH1 and CH2 stay free for the analog work the linear topology is genuinely good at — op-amp rails, sensor bias, charge-pump references, audio circuits — while CH3 handles whatever digital subsystem the project also needs powered. One supply, two adjustable analog rails, one switchable digital rail, all labeled, all protected, all SCPI-controllable.
UNI-T UDP3303C — ch3 logic-rail selector
SCPI Programmable for Repeatable Bench Work
The UDP3303C is the programmable counterpart to the UDP3303A — same hardware, same protection, same CH3 logic-rail selector — with a back-panel USB-Device port and RS-232 added for SCPI control. Script the rails over USB or RS-232, capture readbacks, document the run, and repeat it tomorrow morning the same way. Programming accuracy holds inside ≤0.1% + 30 mV on voltage and ≤0.5% + 2 mA on current — fine enough for IoT sleep-mode current characterization, battery-charge cut-off testing, and any sweep that needs the setpoint to land where you asked it to. Five preset storage groups (M1–M5) and a Digital I/O hardware ON/OFF pin pair round out a programmable supply built for benches that have to behave the same way every time.
UNI-T UDP3303C — scpi programmable for repeatable bench work
Applications
R&D Bench & Prototyping
Three rails (two adjustable, one switchable digital) with SCPI control script the bench setup directly from your test framework. Linear topology and ≤1 mVrms ripple keep supply noise out of measurement on op-amp characterization, ADC reference rails, and sensor-bridge excitation work.
Automated Test Lab Integration
SCPI over USB-Device or RS-232 integrates with LabVIEW, Python-VISA, and shell-driven test frameworks. Five preset storage groups keep frequently used test setups one command away. Programming accuracy ≤0.1% + 30 mV keeps automated sweeps repeatable across runs.
Teaching Labs & Automated Lab Exercises
For curricula that introduce instrument automation alongside instrument operation, the UDP3303C lets a class go from manual front-panel work to scripted SCPI control without changing the instrument.
Mixed-Signal Development
CH1 and CH2 power analog rails at low ripple; CH3 cycles through digital-side voltages without retuning. SCPI lets the test script raise or lower the digital rail while CH1/CH2 hold the analog supplies steady — useful for power-sequencing and sleep-mode characterization on mixed-signal prototypes.
Specifications
| Model | UDP3303C |
| Channels | 3 programmable (CH1, CH2 adjustable; CH3 selectable) + CH4 USB charging output |
| CH1, CH2 Output Voltage | 0–30V |
| CH1, CH2 Output Current | 0–3A |
| CH3 Output Voltage | 1.8V / 2.5V / 3.3V / 5V (±3%, fine-tunable) |
| CH3 Output Current | 3.2A |
| Total Output Power | 195W |
| CH4 USB Charging Output | 5V / 2A (front-panel USB charging output) |
| Voltage Resolution | 10 mV |
| Current Resolution | 1 mA |
| Load Regulation (CV) | ≤0.01% + 3 mV |
| Load Regulation (CC) | ≤0.2% + 3 mA |
| Programming Accuracy (Voltage) | ≤0.1% + 30 mV |
| Programming Accuracy (Current) | ≤0.5% + 2 mA |
| Ripple & Noise (Voltage) | ≤1 mVrms (20Hz–20MHz) |
| Ripple & Noise (Current) | ≤3 mArms |
| Temperature Coefficient | ≤300 ppm/°C (V/I) |
| Series Mode (CH1+CH2) | Up to 60V (CH1+CH2) |
| Parallel Mode (CH1+CH2) | Up to 6A (CH1+CH2) |
| Display | EBTN LCD, 4-digit voltage + current per channel |
| Programmable | Yes — SCPI over USB-Device or RS-232 |
| Interfaces | USB-Device, RS-232, Digital I/O |
| Memory | 5 preset storage groups (M1–M5) |
| Protection | OVP, OCP (per-channel, configurable), OTP, keypad lock, shutdown memory |
| AC Input | 100 / 120 / 220 / 230V ±10%, 50/60 Hz |
| Dimensions (W × H × D) | 240 × 168 × 347 mm |
| Weight | 8.8 kg |
| Certifications | CE |
Frequently Asked Questions
What's the difference between the UDP3303A and the UDP3303C?
The UDP3303C adds SCPI programmability over USB-Device and RS-232. Hardware (channels, voltage, current, power, CH3 logic-rail selector, protection, display, dimensions) is otherwise identical. Choose the UDP3303A if your bench is knob-only; choose the UDP3303C if you need automated test integration. For 5A per adjustable channel instead of 3A, step up to the UDP3305C.
Does the UDP3303C have LAN?
No. The UDP3303C's data interfaces are USB-Device (back-panel SCPI port for PC connection) and RS-232. If your workflow needs LAN with LXI/web interface, the UDP3000S series adds it on the same linear-PSU platform. The Digital I/O pin pair on the back panel handles hardware ON/OFF — useful for external interlocks but not for data communication.
What is the front-panel USB port for?
It's a 5V/2A USB-A charging output (CH4) — for charging a phone or powering a USB-powered demo board. It is explicitly not a data interface. The SCPI data ports are on the back panel: USB-Device and RS-232.
Can the UDP3303C run automated voltage/current sweeps?
Yes — SCPI control over USB-Device or RS-232 supports remote voltage and current setpoint commands plus readbacks, and the five preset storage groups (M1–M5) keep frequently used configurations available for fast recall. For complex programmable waveform output (list/delayer functions), the UDP3000S series adds those capabilities on the same linear platform.
Why a linear supply instead of switching for SCPI work?
Linear topology produces fundamentally cleaner output — no switching frequency, no harmonic spurs, ripple under 1 mVrms. SCPI control gives you automation; linear regulation keeps the output clean enough for the precision measurements that automated test usually exists to take in the first place. The trade-off is lower efficiency and more heat, which at 195W bench-supply scale is not a meaningful constraint.
What's included with the UDP3303C?
The UDP3303C ships with the instrument, power cord, USB communication cable (UT-D14), RS-232 communication line, alligator clip test leads, English user manual Ships from authorized US dealer.
Warranty
This instrument is backed by UNI-T's 3+2 Year Warranty — 3 years of standard coverage, plus 2 additional years free when you register your product. That's 5 years of total protection at no extra cost.
The warranty covers manufacturing defects and component failures under normal use conditions. UNI-T instruments are built for professional daily use, and our warranty reflects that commitment to long-term reliability.
Data Sheets and Manuals
Software / Firmware Downloads
Authentic UNI-T accessories are an affordable way to extend the functionality of your instrument.
