Pre-amplifier with cryogenic calibration of noise and gain.

Singled ended configuration

Gain: fixed X1000 for high impedance measurement system.
fixed X600 for 50 ohm measurement system

Bandwidth: 3Hz to 10MHz

Output impedance: 50 ohms.

This amplifier can be optimized for various source impedances:

Noise Properties
1 — en = 850pV/rtHz, in = 4.1 fA/rtHz, Ropt=210Kohm
2 — en = 600pV/rtHz, in = 4.2 fA/rtHz, Ropt=140Kohm
3 — en = 420pV/rtHz, in = 4.4 fA/rtHz, Ropt=95Kohm
4 — en = 300pV/rtHz, in = 4.7 fA/rtHz, Ropt=64Kohm (standard)

Input Properties
1 — Cin = 8pF, Ib = 2.5pA, Rin = 1GOhm
2 — Cin = 16pF, Ib = 5pA, Rin = 1GOhm
3 — Cin = 32pF, Ib = 10pA, Rin = 1GOhm
4 — Cin = 64pF, Ib = 20pA, Rin = 1GOhm

The input is protected with low leakage ESD diodes.

pV = 10^-12V, fA = 10^-15A, pA = 10^-12A
Ropt is the optimal source impedance. Cin is the input capacitance. The resistance to ground on the input is 1Gohm, Ib is the input bias current.

The standard amp is variant 4 which is optimal for measuring quantum devices with single quantum channels. Variant 1 is ideal for very high input impedance measurements from sources such as capacitive microphones.

We can adjust the gain if x1000 is not quite optimal for your application.

These amplifiers are typically about a factor of 10 lower noise than the standard voltage amplifier from Stanford Research, and the input noise on a typical lockin amplifier.

We supply an external power supply which can accept 90VAC-240VAC (47-63Hz), and connects to the amplifier with a standard 5-pin DIN. If you would like a different power connector, please send this to us.

Warm-up time is ~5min. This can be shortened at the cost of slightly increased low frequency noise (<100Hz).

The noise and gain characteristics of each amplifier are carefully measured before shipment through a series of noise density measurements using cryogenic loads.

If these parameters are not quite right for you, send us an note and describe your application (source impedance, cables, frequency, ect) and lets see if we can make something perfect for you.