The QDAC-II
Ultra-low noise and ultra-stable multi-channel voltage source
QDAC-II is the next generation of the successful QDAC from QDevil. It has all the outstanding features from its predecessor but is even more versatile and with superior performance.

QDAC-II is a high-precision ultra-low-noise computer controlled DAC with 24 voltage generators, operating at a sample rate of 1MS/s – a thousand times faster than its predecessor. It is designed for DC and intermediate-frequency control of quantum devices, including, for example, gate electrodes and flux bias coils in qubits, but is a very versatile instrument that can be used for many other purposes. Each of the 24 channels has five voltage generators working in parallel: One for DC, a sine generator, a triangle generator, a square wave generator, and an arbitrary waveform generator (1 million points/second). Additionally, each channel is equipped with a DC current sensor with a resolution down to a few tens of pA, typically used for gate leakage detection and with sample rates up to 3 kHz.
All in all, the QDAC II offers a high-performance cost-effective solution with multiple expansion capabilities.
What are the highlights?
- Ultra-low noise and ultra stable multi-channel voltage source.
- 24 individual DAC channels.
- Unique low pass output filter design, with 3 ranges that can be switched between with minimal transients. The high bandwidth mode has a cut-off of 300 kilohertz, the medium bandwidth mode has a cut-off of 10 kilohertz, and the DC mode has a cut-off of 10 Hz.
- 25 bit resolution in DC mode (10 Hz cut-off), 20 bit in medium bandwidth mode (10 kHz cut-off) and in high bandwidth (fast) mode (300 kHz cut-off) and one million samples per second.
- Each channel has multiple standard waveform generators and an arbitrary waveform generator.
- Individual high resolution low-frequency current sensors on every channel, measuring current simultaneously on all channels.
- Advanced triggering and synchronization functions between channels with sub-microsecond precision.
- Controlled via galvanically isolated gigabit ethernet or opto-coupled USB.
- Galvanically isolated trigger inputs and outputs, to avoid ground loops.
- Multiple QDAC-II units can be synchronized.
- External galvanically low-noise linear power supply, to be placed at some distance from the instrument, to minimize 50/60 Hz noise.
Watch the product video of the QDAC-II here.
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