E. Noah, CMS Tracker Week, January 2003

APV Power Dependence on Trigger: First Observations on Hybrid

• Effect first observed in Strasbourg and reported by Jean-Daniel Berst.

• Large drop in hybrid current when the trigger is removed. I250 ~ 230 mA for a 6 APV module

I250 ~ 160 mA for a 4 APV module (from 660 mA to 500 mA)

• Following the removal of triggers, the current decreases slowly and stabilises with a time constant of a few seconds.

• Normal current is sustained with trigger rates above a few Hz

E. Noah, CMS Tracker Week, January 2003

First Observations on a Hybrid

• Where does the current change occur on the hybrid?

• What is its dependence on trigger rate?

• What is its exact magnitude?

• How important will this effect be for CMS?

E. Noah, CMS Tracker Week, January 2003

Measurements on the APV25

• I125 does not vary with trigger status but I250 does.

• Hint that current drop is related to the analogue bias. Look at how the current changes with bias register settings.

Breakdown of current drawn byvarious sub-circuits, per channel

Sub-circuit I250 [A] I125 [A] Power [mW] Preamplifier 60 400 0.65

Preamp. Source Follower 50 0.125 Inverter 100 0.125 Shaper 50 0.125

Shaper Source Follower 50 0.125 APSP 80 0.2

MUX Input Stage 30 0.075 Output Stages 188 0.47

Digital 164 0.41 Total/Channel 692 500 2.31

E. Noah, CMS Tracker Week, January 2003

Measurements on the APV25

• Dependence on mode register:– With no trigger applied, I125 and I250 are

constant, independent of the mode register setting.

– Increase in current is:• Independent of inverter stage

• Higher for 20MHz multiplexer frequency

• Slightly higher in peak mode

20

15

10

5

0

I 25

0(T

rigg

er)

- I 2

50(

No

Trig

ge

r) [

mA

]

Inv/

20

MH

z/d

c/C

alO

ff/3

sam

ple

s/B

iasO

n

No

n-I

nv/

20

MH

z/d

c/C

alO

ff/3

sam

ple

s/B

iasO

n

Inv/

40

MH

z/d

c/C

alO

ff/3

sam

ple

s/B

iasO

n

No

n-I

nv/

40

MH

z/d

c/C

alO

ff/3

sam

ple

s/B

iasO

n

Inv/

20

Mh

z/p

k/C

alO

ff/1

sam

ple

/Bia

sOn

No

n-I

nv/

20

MH

z/p

k/C

alO

ff/1

sam

ple

/Bia

sOn

Inv/

40

MH

z/p

k/C

alO

ff/1

sam

ple

/Bia

sOn

Inv/

20

MH

z/p

k/C

alO

n/1

sam

ple

/Bia

sOn

E. Noah, CMS Tracker Week, January 2003

Measurements on the APV25• Dependence on IPSP, VPSP and ISHA

• Virtually no dependence on any of the other bias generator settings: Current drop when the trigger is removed probably occurs in the APSP (pulse shape processor).

20

15

10

5

0

I 25

0(T

rig.)

-I25

0(N

o T

rig.)

[m

A]

250200150100500

IPSP Register Value

50

40

30

20

10

0

I 25

0(T

rig.)

-I25

0(N

o T

rig.)

[m

A]

6040200

VPSP Register Value

30

20

10

0

I 25

0(T

rig.)

-I25

0(N

o T

rig.)

[m

A]

250200150100500

ISHA Register Value

E. Noah, CMS Tracker Week, January 2003

Measurements on a Hybrid

• 4 x APV module• Measure:

– Hybrid current with clock and trigger– Hybrid current with clock but without trigger– Hybrid current without both clock and trigger

• Check that measurements are consistent with those carried out on the stand alone APV25.

E. Noah, CMS Tracker Week, January 2003

Measurements on a Hybrid

• By switching off the analogue bias on any combination of APVs, consistency with the results obtained on ‘stand alone’ APV is confirmed. drop occurs in APVs

• When the clock is removed, the decrease in current is much larger because of current drop in digital circuitry. Idig = 85mA

60

40

20

0

I(T

rig.)

-I(N

o T

rig.)

[m

A]

All

4 c

hip

s

Ch

ip 1

on

ly

Ch

ip 2

on

ly

Ch

ip 3

on

ly

Ch

ip 4

on

ly

Ch

ips

1 &

2

Ch

ips

3 &

4

Chips with analogue bias enabled on hybrid

Difference in hybrid currentwith and without trigger

120

80

40

0I(

Clo

ck)-

I(N

o C

lock

) [m

A]

All

4 c

hip

s

Ch

ip 1

on

ly

Ch

ip 2

on

ly

Ch

ip 3

on

ly

Ch

ip 4

on

ly

Ch

ips

1 &

2

Ch

ips

3 &

4

Chips with analogue bias enabled on hybrid

Difference in hybrid currentwith and without clock

E. Noah, CMS Tracker Week, January 2003

Measurements on a Hybrid• Dependence of current drop on bias register settings when the trigger is removed

150

100

50

0

I(T

rig.)

-I(N

o T

rig.)

[m

A]

6040200

VPSP Register Value

Difference in hybrid current with/without trigger vs. VPSP

250200150100

500

I(C

lock

)-I(

No

Clo

ck)

[mA

]

6040200

VPSP Register Value

Difference in hybrid currentwith/without clock vs. VPSP

80

60

40

20

0

I(T

rig.)

-I(N

o T

rig.)

[m

A]

250200150100500

IPSP Register Value

Difference in hybrid currentwith/without trigger vs. IPSP

200

150

100

50

0

I(C

lock

)-I(

No

Clo

ck)

[mA

]

250200150100500

IPSP Register Value

Difference in hybrid currentwith/without clock vs. IPSP

80

60

40

20

0

I(T

rig.)

-I(N

o T

rig.)

[m

A]

250200150100500

ISHA Register Value

Difference in hybrid currentwith/without trigger vs. ISHA

200

150

100

50

0

I(C

lock

)-I(

No

Clo

ck)

[mA

]

250200150100500

ISHA Register Value

Difference in hybrid currentwith/without clock vs. ISHA

• Dependence of current drop on bias register settings when the clock is removed

E. Noah, CMS Tracker Week, January 2003

Comparing Measurements• Hybrid measurements

5040302010

0

I(T

rig.)

-I(N

o T

rig.)

[mA

]

6040200

VPSP Register Value

Hybrid current drop(per chip)with/without trigger vs. VPSP

50

40

30

20

10

0

I 250

(Trig

.)-I

250(N

o T

rig.)

[mA

]

6040200

VPSP Register Value

• APV25 measurements

Dig. header Analogue baseline

Decreasing VPSP: higher baseline larger current drop

E. Noah, CMS Tracker Week, January 2003

Trigger Rate Dependence

• Measurement is made by: – Applying trigger at a

rate defined by external pulse generator.

– Recording maximum and minimum power supply currents.

• For trigger rates above 10 Hz, hybrid current is stable.

200

150

100

50

0

I MA

X -

I MIN

[m

A]

10-1

100

101

102

103

104

Trigger frequency [Hz]

VPSP = 50 VPSP = 42, baseline at 1/4 of dig. header VPSP = 32, baseline at 1/2 of dig. header VPSP = 20 VPSP = 10 VPSP = 0, baseline above dig. header

Drop in hybrid current as a function of trigger frequency

E. Noah, CMS Tracker Week, January 2003

Summary• I250 drops with low trigger rates applied to hybrids:

– Trigger removal initiates a current drop which occurs with a time constant of ~ seconds.

– When trigger is applied, current rises rapidly.

• Effect originates in the APVs, probably the APSP since it is sensitive to VPSP, IPSP and ISHA.

• For a hybrid operated with default settings and APV analogue baseline ¼ of digital header, drop in current is 10%.

• Effect of removing the clock was also measured: current drop is much larger because of contribution from digital circuitry.

E. Noah, CMS Tracker Week, January 2003

Strasbourg Results, 6-APV Hybrid

• Drop in current is large but note that VPSP=20, so baseline is high.

E. Noah, CMS Tracker Week, January 2003

Strasbourg Results, 4-APV Hybrid

• 4-APV hybrid, same bias register settings as those used at IC. Similar current drop but time constant is much larger.

E. Noah, CMS Tracker Week, January 2003

Effect of removing the clock on Hybrid

Itot = Idig + Iana

Case 1:Trigger is removed. Idig = 0

tot = Iana = 51mA

Case 2: Clock is removed. Itot = 136 mA

Idig = Itot – Iana = 85 mA

APV manual states 164 A/channel, 21 mA/chip

Drop due to digital circuitry is constant.

60

40

20

0

I(T

rig.)

-I(N

o T

rig.)

[m

A]

All

4 c

hip

s

Ch

ip 1

on

ly

Ch

ip 2

on

ly

Ch

ip 3

on

ly

Ch

ip 4

on

ly

Ch

ips

1 &

2

Ch

ips

3 &

4

Chips with analogue bias enabled on hybrid

Difference in hybrid currentwith and without trigger

120

80

40

0

I(C

lock

)-I(

No

Clo

ck)

[mA

]

All

4 c

hip

s

Ch

ip 1

on

ly

Ch

ip 2

on

ly

Ch

ip 3

on

ly

Ch

ip 4

on

ly

Ch

ips

1 &

2

Ch

ips

3 &

4

Chips with analogue bias enabled on hybrid

Difference in hybrid currentwith and without clock