1 design review slow control part hervé mathez ipnl cnrs slow control part in fppa 2000/2001

1

Design Review Slow Control Part

Hervé MATHEZ IPNL CNRS

SLOW CONTROL PARTIN

FPPA 2000/2001

2



LEAKAGE CURRENT SPECIFICATIONS

Input : 20nA to 20µA for twin APD Leakage current return to ground (only FPPA gnd point)

No schematic changes between FPPA2000 and FPPA2001

APD anode voltage must be stabilized at ± 25 mV (Rp, HV) Minimum leakage current to be measured ± 200 nA (Il(T), T) Non linearity over full scale is 1% Low input bias current amplifier Output 0.5 V to 2.5V compatible with FPU input

3



TEMPERATURE MEASUREMENT SPECIFICATIONS

Range : 5°C to 25°C T to be measured : ± 0.1°C Current measurement through a thermistor (R25°C = 100 k, = 3960 K)

between 2 constant voltages (2.4V and 1.2V, self heating)

Input current : 4.3 µA to 12 µA @ 18°C, 0.1°C is 40 nA Constant voltage must stabilized at ±5 mV Non linearity : 0.3% Output 0.5 V to 2.5V compatible with FPU input

No schematic changes between FPPA2000 and FPPA2001

4



+

-

+

-

C*Vref ADC

+ -

HV

APD

Rf

Rp

Vout (ILeakage)

ADC Output = f (VrefADC,Rf)External componentsOTA2 Open loop gain 90dB, Fc< 1kHz, with output capacitor of 5pF

Phase margin 80° (Also used in temperature measurement)OTA1 is modified in order to Vanode APD goes to 0V

Open loop gain 65dB, Fc< 20kHz, with output capacitor of 5pFPhase margin 80°

HOW TO DO LEAKAGE CURRENT MEASUREMENT ?

OTA1

OTA2

5



C*Vref ADC

+

-Vout (dummy)

Rf

Rf

C*Vref ADC

-

-

B*Vref ADC

B*Vref ADC

+

-+

-

+

+

A*Vref ADC

A*Vref ADC+

-

+

-

Roff

R(T)

Rdummy

VCC

Vout (T)

A*Vref ADC

ADC Output = f (R(T),Roff ,Rf)External componentsAll same OTA have input bias current compensated

HOW TO DO TEMPERATURE MEASUREMENT ?

6



OTA FOR BOTH MEASUREMENTS

OTA 1OTA 2

GdB=90 dBPhase Margin=80°

GdB=65 dBPhase Margin=80°

7



LEAKAGE CURRENT MONTE CARLO ANALYSIS(FPPA2000)

Vout LEAK [V] = f(I leak) [µA]

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20

Linearity Error [%PE] = f(Run Monte Carlo I leak)

0

0.5

1

1.5

2

2.5

3

0 10 20 30 40 50

0.5 V < Vout < 2.5 V < 1 %

8




V anode APD [mV] = f(I leak) [µA]

-1.2E-02

-1.0E-02

-8.0E-03

-6.0E-03

-4.0E-03

-2.0E-03

0.0E+00

2.0E-03

4.0E-03

6.0E-03

8.0E-03

1.0E-02

0 2 4 6 8 10 12 14 16 18 20

Delta V anode APD [µV] = f(Run Monte Carlo)

0

200

400

600

800

1000

1200

1400

1600

0 10 20 30 40 50

V anode APD 1.4 mV

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I inm OTA_N_IL [A] = f(I leak) [µA]

-1.E-07

-8.E-08

-6.E-08

-4.E-08

-2.E-08

0.E+00

2.E-08

4.E-08

6.E-08

8.E-08

1.E-07

0 5 10 15 20

Delta I inm OTA_N_IL [A] = f(Run Monte Carlo)

0.0E+00

2.0E-10

4.0E-10

6.0E-10

8.0E-10

1.0E-09

1.2E-09

1.4E-09

1.6E-09

0 10 20 30 40 50


Input Bias Current < 50 nA (except for 5 MC run)

Very low variation versus input current

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TEMPERATURE MEASUREMENT MONTE CARLO ANALYSIS(FPPA2000)

Vout [V] = f(I ntc) [µA]

0.30

0.80

1.30

1.80

2.30

2.80

4 6 8 10 12

Linearity Error [%PE] = F(Run Monte Carlo I ntc)

0

0.02

0.04

0.06

0.08

0.1

0.12

0 10 20 30 40 50

0.5 V < Vout < 2.5 V << 0.1 %

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Delta V ntc [µV] = f(Run Monte Carlo)

30

35

40

45

50

55

60

65

70

0 5 10 15 20 25 30 35 40 45 50

IRoff [µA] = f(Run Monte Carlo)

-4.33E-06

-4.32E-06

-4.31E-06

-4.30E-06

-4.29E-06

-4.28E-06

-4.27E-06

-4.26E-06

-4.25E-06

-4.24E-06

-4.23E-06

0 5 10 15 20 25 30 35 40 45 50

TEMPERATURE MEASUREMENT MONTE CARLO ANALYSIS(FPPA2000)

1.2 V Voltage variation across R(T)over the full range

Offset current for 50 MC run

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SUMMURAY OF MONTE CARLO ANALYSIS(FPPA2000)

Temperature

Input Current

Leakage

Input Current

Additional BJT to providehigh reverse voltage Base-Emitter noticed by MC simulations

All other simulations(transient) are correct

Offset Current Ouput

Voltage reference

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CONCLUSION(FPPA2000)

SLOW CONTROL PART WORKS WELL

AND ALLMEASUREMENTS

ARE INSPECIFICATION

1 design review slow control part hervé mathez ipnl cnrs slow control part in fppa 2000/2001

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