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Handheld Precision Digital Voltage Source - PDVS2mini 20bit

A handheld Precision Digital Voltage Source, true 0.00000V to 10.00000Vdc range, battery powered.
Total Price: £199.99
Price excl. VAT (EU only): £199.99
VAT (EU only):
Price / kg:
Product Available Date: 2019-07-01

Model: PDVS2mini 20bit
Handmade in Great Britain by Ian Johnston
NEW FOR 2019, THE PDVS2mini 20bit GIVES A TRUE 0.00000 TO 10.00000Vdc IN 10uV STEPS USING A NEW 20bit DAC.
Price, specification, functions, appearance & availability subject to change, I'm still in the R&D stage!

A smaller, more affordable sister product to the PDVS2, this is a truly handheld Precision Digital Voltage Source.
With a user adjustable range from a true 0V to 10Vdc and an accuracy/stability down in the uV’s it has a multitude of uses as a calibrator, reference & precision voltage source.


Built on the success of the PDVS2 I figured I would attempt to make a more affordable version and started with a plain non-custom enclosure and went to work.
No rotary encoder, no 12-button keypad, no USB interface......but certain criteria & functionality had to be retained however:- Dual Lithium-Ion batteries c/w charging circuit, 4mm banana sockets and a graphics LCD. It uses a MAX5719A which is a 20bit DAC and has a higher resolution than used in the PDVS2 (but a higher INL - Intergral Non-Linearity where lower is better)................I've called this new product the PDVS2mini.


  • True 0 Vdc to 10 Vdc user adjustable output (5d.p’s, approx. 10uV steps)
  • Voltage setting via up/down pcb pushbuttons
  • Soft power switch
  • Based on the industry standard LM399AH (0.5 ppm/degC) voltage reference
  • All digital calibration, no internal potentiometers
  • 20bit DAC with an accuracy/stability down in the uV’s (using a PLC filter of 1.0 or higher)
  • Battery voltage monitor, including low voltage warning, auto-shutdown and charging status
  • Output voltage monitor including short circuit protection
  • 2.4” Graphics Monochrome LCD (128x64 pixels)
  • Atmel Atmega1284 micro-controller (uses Arduino bootloader)
  • Precision chopper op-amp on final output with extra stability achieved using low tempco resistors
  • Re-calibration by the user possible, and saved to flash rom
  • Charging pcb/socket for Li-ion batteries using a battery management IC. Batteries and DC adaptor are not supplied
  • Battery reverse polarity protection
  • ABS Hammond enclosure
  • Manual including factory calibration/settings test record. Unique serial number
  • CE approved

Prior to shipping each unit assembled & tested in-house, aged/burned-in for 120hrs and calibrated with a HP3458a 8.5 digit multimeter (Keysight Cal. 08/03/19) at constant ambient temp.
In the box - 1off PDVS2mini (no batteries, no charger), 1off Charging connector c/w tail, Calibration record and details of the PDF Manual (c/w CE Declaration of Conformity).

NOTICE: VAT registered EU companies please contact me prior to purchase to receive instructions on how to zero rate the VAT.


  • Voltage reference = LM399AH (0.5 - 1 ppm/degC temperature coefficient)
  • 0.00000 Vdc to 10.00000 Vdc in 10 uV (0.00001 Vdc) steps
  • Load = 3kohm minimum. Example: At 10Vdc output with 3kohm load = 3.3mA (whilst maintaining output within approx. 10uV)
  • Accuracy = Within 100uV. Typically 0.001% at 10V output - SPEC TO BE CONFIRMED
  • Stability = 0.0001Vdc typical variation. Orientation of the unit may effect output (calibrated horizontally), as will powering from external DC - SPEC TO BE CONFIRMED
  • Temperature coefficient (unit) = 2.5 ppm/degC typical (Actual test results: 0.000024Vdc change over 8.8degC temp change, 45min duration) - SPEC TO BE CONFIRMED
  • Drift (12 months typical) = tba - SPEC TO BE CONFIRMED
  • Stabilization time = 10mins to 1hr depending in ambient temperature and last use - SPEC TO BE CONFIRMED
  • Output short circuit = indefinite (20mA)
  • Power (batteries) = Two Lithium-Ion re-chargeable 9V PP3 batteries (Not supplied, 600mAh batteries recommended)
  • Power (external power)  = 18 to 24Vdc input (also charges the batteries) @ 400mA min recommended
  • Battery = Approx. 12hrs (EBL 600mAh re-chargeable batteries) typical continuous operation
  • Current drain = 45mA approx. (after 10mins) - SPEC TO BE CONFIRMED
  • Dimensions = 106mm x 66mm x 47mm


  • PDVS2mini 20bit Firmware - V1.00 (July 2019) is shipped with all units.
  • PDVS2mini 20bit Manual - For V1.00 firmware - Download tba.


The user can re-calibrate the PDVS2mini 20bit via the Calibration menu. The PDVS2mini 20bit uses multi-setpoint X-Y calibration (rather than simple Zero & FSD) in order to help reduce DAC INL (Integral nonlinearity).


Batteries are not supplied so customers must supply their own and we highly recommend 600mAH or better Li-ion PP3 batteries from EBC or Etinesan (I did a battery test here). These will give you 12-14hrs continous use between charges.
A DC adaptor or power supply is required (not supplied) to charge the batteries and should be rated at 18V - 25Vdc @ 0.4A. A compatible plug with tails is supplied.
Is the charging safe? - I have implemented a current-limited, switch-mode Li+ charger/controller and am running it quite low (0.25A charge current) to avoid any issues. The software also monitors the charge current and can shut it down.
The batteries I recommend have protection circuitry built in as an added layer of protection for under-voltage and over-charging.
Important: The PDVS2mini 20bit is optimized and primarily designed for battery operation, the calibration & stability of the PDVS2mini 20bit is only supported under battery usage. External DC adaptors/PSU's (not supplied) through common mode noise may inhibit accuracy.


Standard 4mm banana sockets (19mm apart).
1 soft power pushbutton & 5 others for navigating the menus and selecting of the digits for changing the output voltage.
2.4" graphics LCD.
Battery charge socket.
(please ignore test header sticking out the side)


Standard 106mm x 66mm x 33mm Hammond enclosure.
4 screws allow access to the internals/batteries.


Semi-open frame design helps keep costs to a minimum.


Uses the same microcontroller, charging circuit and DC power circuit as the PDVS2, albeit there's a new 20bit DAC IC.
Shown here is the underside of the PCB with much of the electronic components, the battery holders and the vertical charge PCB.


Both sides of the protptype PCB. 2-layer gold plated (the charge PCB snaps off prior to assembly).
PS. I use Altium's CircuitStudio if you wanted to know.