• CryoHEMTs: chip or packaged in ceramic SOT23
  • CryoHEMTs based cryogenic preamplifiers

CryoHEMTs: chip or packaged in ceramic SOT23

Characteristics of available cryoHEMTs with various gate-surface measured at 4.2 K, Ids = 1 mA and Vds = 100 mV:

Denomination 200pch 100pch 30pch 5pch 1pch
LgxW (µm²) 1.5×105 6.4×104 2.0×104 2.0×103 4.0×102
Cgs (pF); Cgd (pF) 236; 8.9 103; 8.9 33; 3.5 4.6; 1.0 1.8; ~0.6
Vds(mV); Ids(mA) 100; 1.0 100; 1.0 100; 1.0 100; 1.0 100; 0.5
gm (mS); gd (mS) 52; 0.4 40; 1.2 115; 1.3 44; 1.3 15; 0.8
ft = gm/(2πCgs) (Hz) 3.5×107 6.2×107 5.5×108 1.5×109 1.3×109
en (nV/Hz½) @1Hz
@10Hz
@100Hz
@1kHz
~ 5.4
~ 1.8
~ 0.55
~ 0.25
11 – 14
4 – 5
~ 1
~ 0.4
~ 15
~ 5.5
1.5 – 2
0.6 – 0.7
35 – 50
10 – 15
2.5 – 5
0.75 – 1.2
80 – 100
30 – 40
8 – 10
2 – 4
en-white (nV/Hz½) ~ 0.18 ~ 0.21 0.15 – 0.18 ~ 0.24 0.4 – 0.5
in (aA/Hz½) @1Hz
@1kHz
21
6.8×102
15
5.1×102
9.1
2.4×102
2.2
70
3.6
57
cryoHEMT chip
cryoHEMT in ceramic SOT23

LgxW is the gate surface; Cgs, the gate-source capacitance; Cgd, the gate-drain capacitance; Vds, the drain-source bias; Ids, the drain-source current; gm, the transconductance; gd, the output conductance; ft, the current-gain cutoff frequency;  en, the equivalent input noise voltage; en-white, the equivalent input white noise voltage; in, the equivalent input noise current. Noise current is measured with the help of the capacitance input setup shown in the reference Appl. Phys. Lett. 105, 13504 (2014).

CryoHEMTs based cryogenic preamplifiers

Various cryogenic readout electronics have been realized with cryoHEMTs and performed (see papers in “PUBLICATIONS”), a few examples are as below. We can propose and provide several types of cryo-amp to meet specific experimental requirement, e.g., set the output impedance of 50Ω for operating frequency » 1 MHz; minimize the Miller effect and the input capacitance by adding a follower (common-drain amp). All our cryo-amps can be modified and optimized to fit user’s needs.

Datasheet of following plug-and-play cryo-amps are biased with two votage sources. The cryo-amps can also be biased with only one voltage source, but the datasheet can be changed, e.g., the low-frequency limit and the power dissipation. The box dimension (without SMA and feedthrough) of the cryo-amps is 36mmX26mmX8mm.

The cryo-amp A5-1 is based on a 5pch with the DC coupling input: datasheet and some of resulted publications:

Model: A5-1 5pch cryoHEMT
Operating temperature ≤ 4.2 K
Input coupling DC
Input impedance 11 pF // 1016 Ω
Output couplingDC
Output impedance 132 Ω
*Bandwidth, including the input
impedance of 50 Ω, the power
lines’ resistance of 1 Ω and the
output cable’s capacitance of 200 pF
0 Hz – 6 MHz
**Voltage gain Avo ~ 5
***Vout_p-t-p = 90 mV Av/Avo = 95%
Power dissipation ~ 0.35 mW
HEMT’s
Noise voltages @ 4.2 K
9.8 ~ 12 nV/Hz½ at 10 Hz
0.66 ~ 0.93 nV/Hz½ at 1 kHz
0.25 nV/Hz½ at 100 kHz
0.24 nV/Hz½ at 1 MHz
**** HEMT’s
Noise currents @ 4.2 K
6 aA/Hz½ at 10 Hz
62 aA/Hz½ at 1 kHz
0.7 fA/Hz½ at 100 kHz
2 fA/Hz½ at 1 MHz

* The high frequency limit partially depends on amp’s output impedance and the capacitance of the cable that connects the cryo-amp to the room temperature electronics. By setting 50 Ω output, the cutoff frequency can be about 420 MHz. ** Avo is the small signal voltage gain.  Avo can be increased (or decreased) by increasing (or decreasing) the output impedance, the change of the output impedance induces the change of the power dissipation and the high-frequency limit of the cryo-amp. *** The voltage gain Av depends on its output peak-to-peak amplitude Vout_p-t-p, Av decreases with the increase of Vout_p-t-p due to the limit of the working point.**** The noise current is measured in a HEMT with the same configuration by the capacitor input method, see Applied Physics Letters 105, 1, 013504 (2014)

The cryo-amp A5ac-1 is based on a 5pch with the AC coupling input: datasheet

Amp model: A5ac-1 5pch cryoHEMT
Operating temperature ≤ 4.2 K
Input coupling AC
Input impedance 11 pF // 1.3 GΩ
Output couplingDC
Output impedance 132 Ω
*Bandwidth, including the input
impedance of 50 Ω, the power
lines’ resistance of 1 Ω and the
output cable’s capacitance of 200 pF
12 mHz – 6 MHz
**Voltage gain Avo ~ 5
***Vout_p-t-p = 90 mV Av/Avo = 95%
Power dissipation ~ 0.35 mW
HEMT’s
Noise voltages @ 4.2 K
9.8 ~ 12 nV/Hz½ at 10 Hz
0.66 ~ 0.93 nV/Hz½ at 1 kHz
0.25 nV/Hz½ at 100 kHz
0.24 nV/Hz½ at 1 MHz
**** HEMT’s
Noise currents @ 4.2 K
6 aA/Hz½ at 10 Hz
62 aA/Hz½ at 1 kHz
0.7 fA/Hz½ at 100 kHz
2 fA/Hz½ at 1 MHz

* The high frequency limit partially depends on amp’s output impedance and the capacitance of the cable that connects the cryo-amp to the room temperature electronics. By setting 50 Ω output, the cutoff frequency can be about 420 MHz. ** Avo is the small signal voltage gain.  Avo can be increased (or decreased) by increasing (or decreasing) the output impedance, the change of the output impedance induces the change of the power dissipation and the high-frequency limit of the cryo-amp. *** The voltage gain Av depends on its output peak-to-peak amplitude Vout_p-t-p, Av decreases with the increase of Vout_p-t-p due to the limit of the working point.**** The noise current is measured in a HEMT with the same configuration by the capacitor input method, see Applied Physics Letters 105, 1, 013504 (2014)

The cryo-amp A200-1 is based on a 200pch with the DC coupling input: datasheet

Amp model: A200-1 200pch cryoHEMT
Operating temperature ≤ 4.2 K
Input coupling DC
Input impedance 266 pF // 1016 Ω
Output couplingDC
Output impedance 106 Ω
*Bandwidth, including the input
impedance of 50 Ω, the power
lines’ resistance of 1 Ω and the
output cable’s capacitance of 200 pF
0 Hz – 5.7 MHz
**Voltage gain Avo ~ 5
***Vout_p-t-p = 90 mV Av/Avo = 95%
Power dissipation ~ 0.3 mW
HEMT’s
Noise voltages @ 4.2 K
2 nV/Hz½ at 10 Hz
0.54 nV/Hz½ at 100 Hz
0.24 nV/Hz½ at 1 kHz
0.19 nV/Hz½ at 10 kHz
0.18 nV/Hz½ at 100 kHz
**** HEMT’s
Noise currents @ 4.2 K
70 aA/Hz½ at 10 Hz
0.21 fA/Hz½ at 100 Hz
0.68 fA/Hz½ at 1 kHz
2.1 fA/Hz½ at 10 kHz
6.0 fA/Hz½ at 100 kHz

* The high frequency limit partially depends on amp’s output impedance and the capacitance of the cable that connects the cryo-amp to the room temperature electronics. By setting 50 Ω output, the cutoff frequency can be about 420 MHz. ** Avo is the small signal voltage gain.  Avo can be increased (or decreased) by increasing (or decreasing) the output impedance, the change of the output impedance induces the change of the power dissipation and the high-frequency limit of the cryo-amp. *** The voltage gain Av depends on its output peak-to-peak amplitude Vout_p-t-p, Av decreases with the increase of Vout_p-t-p due to the limit of the working point.**** The noise current is measured in a HEMT with the same configuration by the capacitor input method, see Applied Physics Letters 105, 1, 013504 (2014)

The cryo-amp A200ac-1 is based on a 200pch with the AC coupling input: datasheet

Amp model: A200ac-1 200pch cryoHEMT
Operating temperature ≤ 4.2 K
Input coupling AC
Input impedance 266 pF // 1.3 GΩ
Output couplingDC
Output impedance 106 Ω
*Bandwidth, including the input
impedance of 50 Ω, the power
lines’ resistance of 1 Ω and the
output cable’s capacitance of 200 pF
12 mHz – 5.7 MHz
**Voltage gain Avo ~ 5
***Vout_p-t-p = 90 mV Av/Avo = 95%
Power dissipation ~ 0.3 mW
HEMT’s
Noise voltages @ 4.2 K
2 nV/Hz½ at 10 Hz
0.54 nV/Hz½ at 100 Hz
0.24 nV/Hz½ at 1 kHz
0.19 nV/Hz½ at 10 kHz
0.18 nV/Hz½ at 100 kHz
**** HEMT’s
Noise currents @ 4.2 K
70 aA/Hz½ at 10 Hz
0.21 fA/Hz½ at 100 Hz
0.68 fA/Hz½ at 1 kHz
2.1 fA/Hz½ at 10 kHz
6.0 fA/Hz½ at 100 kHz

* The high frequency limit partially depends on amp’s output impedance and the capacitance of the cable that connects the cryo-amp to the room temperature electronics. By setting 50 Ω output, the cutoff frequency can be about 420 MHz. ** Avo is the small signal voltage gain.  Avo can be increased (or decreased) by increasing (or decreasing) the output impedance, the change of the output impedance induces the change of the power dissipation and the high-frequency limit of the cryo-amp. *** The voltage gain Av depends on its output peak-to-peak amplitude Vout_p-t-p, Av decreases with the increase of Vout_p-t-p due to the limit of the working point.**** The noise current is measured in a HEMT with the same configuration by the capacitor input method, see Applied Physics Letters 105, 1, 013504 (2014)