F-CSA104 contains 4 channels of charge sensitive preamplifiers with differential line drivers. It has particularly been designed for the use with semiconductor radiation detectors operating with liquid nitrogen as coolant (T = 77K/-196°C) .

F-CSA104 joins the formerly discrete input FET with the preamplifier in a single IC, thus forming the next step of integ­ration for better immunity to interference. F-CSA104's noise performance has been optimized for use with capacitive detectors of 0 - 100pF; flicker noise is reduced by use of a p-channel MOSFET as input transistor. In cases where noise matching to higher capacitance detectors is vital, an external p-channel FET may be connected to the IC.

A range of F-CSA104's parameters (including offset and preamplifier decay constant) can be programmed via an I²C interface. F-CSA104's linearity and offset have been designed for use with 14 bit ADC systems, thus being ideally suited for spectroscopy applications.

The high current drive differential line drivers allow for directly driving a 100 Ohm twisted pair cable.

F-CSA104 has been delivered from fab and is currently under evaluation (project in collaboration with Max-Planck-Institut für Kernphysik, Heidelberg).

F-CSA104 Datasheet (pdf, 174kB)

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

ENC_RT

Input equivalent noise charge at room temper­ature

CR-(RC)⁴ shaper, peak time 20µs, AUTOSEL_N=1, RES_FDB_LO=0
C_det = 0 pF
C_det = 30 pF
C_det = 100 pF

120
220
510

electrons
electrons
electrons

FWHM(Si)_RT

“Electronic noise” contribution when used with silicon detector at room temperature

CR-(RC)⁴ shaper, peak time 20µs, AUTOSEL_N=1, RES_FDB_LO=0
C_det = 0 pF
C_det = 30 pF
C_det = 100 pF

1.02
1.87
4.24

keV
keV
keV

ENC_LT

Input equivalent noise charge at -200°C

CR-(RC)⁴ shaper, peak time 20µs, AUTOSEL_N=1, RES_FDB_LO=0, remaining settings “default -200°C”
C_det = 0 pF
C_det = 30 pF
C_det = 100 pF

60
110
240

electrons
electrons
electrons

FWHM(Ge)_LT

“Electronic noise” contribution when used with Germanium detector at -200°C

CR-(RC)⁴ shaper, peak time 20µs, AUTOSEL_N=1, RES_FDB_LO=0
C_det = 0 pF
C_det = 30 pF
C_det = 100 pF

0.417
0.765
1.67

keV
keV
keV

g_m,RT

Input transistor transconductance

I_inp=1mA (INP=h'08), T=27°C

19.7

mA/V

g_m,LT

Input transistor transconductance

I_inp=1mA (INP=h'08), T=-200°C

39.2

mA/V

C_gate

Input capacitance

Input capacitance of input PMOS (W=9000µm, L=0.6µm)

7

pF

A_V

Charge sensitivity
V(OUTP-OUTM) / Q_in

AUTOSEL_N=1, RES_FDB_LO=0, remaining settings “default -200°C”,
Positive input charge Q_in > 0


Negative input charge Q_in < 0

5.84
315.7
258.1
5.84
315.7
258.1

mV/fC
mV/MeV(Ge)
mV/MeV(Si)
mV/fC
mV/MeV(Ge)
mV/MeV(Si)

V_pp

Dynamic range

AUTOSEL_N=1, RES_FDB_LO=0, remaining settings “default -200°C”,
Positive input charge Q_in > 0


Positive input charge Q_in > 0

600
11.1
13.6
600
11.1
13.6

fC
MeV(Ge)
MeV(Si)
fC
MeV(Ge)
MeV(Si)

INL

Integral nonlinearity

AUTOSEL_N=1, RES_FDB_LO=0, remaining settings “default -200°C”, measured after 1µs, LSB (14 bit) refered to dynamic range V_pp
Positive input charge Q_in > 0
Negative input charge Q_in < 0

2
1

LSB
LSB

XT

Interchannel crosstalk

1

‰

T_r

Risetime 10%-90%

Q_in = 40 fC
Q_in = 541 fC (= 10 MeV(Ge) )

22
28

ns
ns

T_s

Settling time for 14 bit accuracy

Q_in = 40 fC, ΔV(OUTP-OUTM)=14 µV
Q_in = 541 fC, ΔV(OUTP-OUTM)=190 µV

560

530

700

700

ns

ns

T_1/2

Preamplifier decay time (half life) for small Q_in

Minimum value: RES_FDB_LO = 1,
FDB[5:1] = h'1F
maximum value: RES_FDB_LO = 0, FDB[5:1] = h'01

0.7

1530

µs

A_o,PA

Preamplifier open loop gain

120

dB

A_o,OP1

Line driver open loop gain

92

dB

ΔV_in

Input voltage shift for max positive/negative signal after settling

0.44

µV

I_DD

Current consumption

No traffic on I²C lines, no signal injected

60

mA

I_DD,CH

Current consumption per channel (VSSA)

No signal injected

9.5

mA