UNI-T UTP3305-II 3Ch Linear DC Power Supply
Overview
The UTP3305-II is the precision-grade refresh of UNI-T's UTP3305 platform — the same 335W three-channel linear topology, with a four-digit LED display reading 10 mV / 1 mA, tighter regulation specs, and a temperature-controlled cooling fan. Two adjustable channels deliver 0–32V at 0–5A; a third channel provides a fixed 5V at 3A for logic-level power. Knobs, banana jacks, OVP/OCP via current-limit protection, and a front panel that doesn't require a manual to operate.
Linear regulation keeps output ripple under 1mVrms with no switching artifacts, no EMI signature competing with the circuit you're actually trying to characterize. CH1 and CH2 combine in series (up to 64V) or parallel (up to 10A). Load regulation tightens to CV <0.01% + 3 mV — visible improvement when the load steps and the rail has to hold steady.
Key Features
- Three Channels, 335W Total — CH1 and CH2: 0–32V / 0–5A adjustable. CH3: fixed 5V / 3A for logic-level power.
- Four-Digit LED Display, 10 mV / 1 mA Resolution — Per-channel voltage and current readouts that read down to 10 mV and 1 mA — fine enough to actually see what the load is doing.
- Tighter Regulation — Load regulation CV <0.01% + 3 mV / CC <0.2% + 3 mA. Tracking accuracy ±(0.1% of reading + 30 mV).
- Linear Topology, ≤1 mVrms Ripple — Clean DC output with no switching frequency, no harmonic spurs.
- Auto CV/CC Crossover — Automatic transition between constant-voltage and constant-current operation when the load steps, with current limit protection.
- Series and Parallel Modes — Combine CH1+CH2 for up to 64V series or 10A parallel — front-panel selectable, no external wiring.
- Temperature-Controlled Cooling Fan — Fan speed scales with internal temperature. Quiet at light loads, full airflow when the supply is working hard.
- Output ON/OFF Control — Front-panel master output button keeps you in command of when current actually leaves the supply.
- Knob-and-Button Operation — No firmware to update, no PC software to install, no LAN port to configure. Front-panel only — designed to behave the same way on day one and year five.
The Precision Upgrade That Costs Almost Nothing
The UTP3305-II keeps the operational simplicity of the UTP3305 — knobs, banana jacks, output ON/OFF — and tightens the parts that matter when your circuit actually responds to the supply. Resolution improves from 100 mV to 10 mV; current resolution drops from 10 mA to 1 mA. Load regulation moves from CV ≤1×10⁻⁴ + 3 mV to CV <0.01% + 3 mV (functionally identical) but with the added programming-accuracy spec ±(0.1% of reading + 30 mV) that the original UTP3305 doesn't publish.
The temperature-controlled cooling fan is a quality-of-life upgrade that matters in classrooms and small-team R&D rooms: the supply is genuinely quiet at moderate loads, and only spins up when you're actually running it hard. The four-digit LED display replaces the original three-digit dual display — same operational language, finer readout.
Applications
Teaching Labs & Trade Schools
Per-station cost that lets a 20-bench classroom stay inside budget, with the precision display students actually need to see what's happening on the rail. Quiet fan operation makes a 30-station lab livable. The 5-year warranty covers a multi-cohort curriculum cycle on one purchase.
Analog Bench Development
10 mV / 1 mA resolution shows the small effects that 100 mV / 10 mA hides — supply load lines, sensor bias drift, op-amp quiescent current. Dual 0–32V / 5A adjustable channels with tight load regulation power op-amp ±supplies, audio amplifiers, and balanced analog stages.
Service & Repair
Reliable bench supply for board-level service work with the resolution to set rails accurately and the current capability to drive higher-power loads. CV/CC auto crossover handles unknown loads safely.
Mixed-Signal Prototyping
Two adjustable rails with master-slave-style behavior in tracking, plus a fixed 5V CH3 for logic, covers most prototyping needs in a single instrument. Linear output stays clean across the full range.
Specifications
| Model | UTP3305-II |
| Channels | 3 (CH1, CH2 adjustable; CH3 fixed) |
| Output Voltage | CH1, CH2: 0–32V CH3: 5V (fixed) |
| Output Current | CH1, CH2: 0–5A CH3: 3A |
| Total Output Power | 335W |
| Voltage Resolution | 10 mV |
| Current Resolution | 1 mA |
| Load Regulation | CV <0.01% + 3 mV CC <0.2% + 3 mA |
| Ripple & Noise | Voltage: ≤1 mVrms Current: ≤3 mArms |
| Tracking Accuracy | ±(0.1% of reading + 30 mV) CC ±(0.3% of reading + 5 mA) |
| Display | 4-digit LED, voltage and current per channel (4 windows) |
| Modes | Independent, Series, Parallel |
| Cooling | Temperature-controlled fan |
| Protection | Current limit protection with auto CV/CC crossover, output ON/OFF |
| Reliability | MTBF ≥ 2,000 hrs |
| AC Input | 115V / 230V AC, 47–63 Hz |
| Dimensions (W×D×H) | 319 × 146 × 226 mm |
| Weight | 10.5 kg |
| Certifications | CE |
| Warranty | 3 years standard + 2 years with free registration (5 years total) |
Frequently Asked Questions
Does the UTP3305-II have USB or SCPI?
No. UNI-T's HQ ordering description literally lists this model as "Non-Programmable Linear DC Power Supply" — there is no USB data interface, no LAN, no SCPI command set, no PC software. If your workflow needs SCPI control, the programmable counterparts in the UNI-T linear PSU family are the UDP3303C and UDP3305C (USB + RS-232) and the UDP3000S series (USB + LAN + LXI with web interface).
What's the difference between the UTP3305 and UTP3305-II?
The "-II" is the precision-grade refresh of the same 335W / 3-channel linear platform: voltage and current resolution improve from 100 mV / 10 mA to 10 mV / 1 mA, the display moves from 3-digit to 4-digit per channel, and the supply gains a temperature-controlled cooling fan and a published programming-accuracy spec. Output ratings, ripple, and feature set are otherwise comparable. Choose -II for finer readout and quieter operation; choose the original UTP3305 if pricing is the dominant factor.
Why a linear supply instead of switching?
Linear topology produces fundamentally cleaner output — no switching frequency, no harmonic spurs, ripple under 1 mVrms. For analog bench work, audio circuits, low-noise sensor development, and any precision measurement where supply noise shows up in the result, the difference is measurable. The trade-off is lower efficiency and more heat, which at this power level on a bench is not a meaningful constraint.
What's included with the UTP3305-II?
The UTP3305-II ships with the instrument, a power cord conforming to the destination country, test output line, English user manual, and UNI-T's 3+2 warranty (3 years standard plus 2 additional years with free registration — 5 years total). 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
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