HB LED Pulser Boards

By

Michael Miller

The University of Iowa

HB LED Pulser Boards• HB Pulser board has the same mechanical format as the HB QIE Card.

Pulser is controlled through the CCA (channel control) ASIC via the RBX Serial Bus. There are 2 semi independent pulsers on the board. Output amplitude is between 1.4 & 5.2 V. LED output light profile is similar to the signal from the megatiles. Board provides 5V biasing for up to 6 independent PIN diodes. For the pulse amplitude the “Pedestal DAC” outputs are used.

Vout=5.2V – N*15.3mV• where N is the 8 bit Pedestal DAC setting. Timing for the two LED pulsers is

derived from the “Test Pulse” CCA output. This 25 ns signal can be masked for channels A and B independently and timed to any bunch crossing of the LHC orbit. Two external inputs facilitate pulser testing and make it possible to work without TTC infrastructure.

• There were several minor changes after the first prototype: 2 extra CCA outputs are used to allow individual triggering for Pulser A and Pulser B. Maximum output DAC voltage was changed from 2.55V to 3.9V to increase the dynamic range of the LED signal.

LED Pulser Board Block Diagram

CCA

Bac

kp

lan

e

8 DAC 3.9V

LED Pulser A

LED Pulser B

External trigger A

External trigger B

LED A

LED B Test Pulse B

Test Pulse A

Pedestal DAC A&B

QIE Range 0

QIE Range 1

Pulser Electrical Diagram

V10V 5V 1000Hz

W1

50 Ohm 1.5e-008 s

R1100ohm

R2

50ohm

C1 0.01uF2

3

5

8 U1

MC100EL16

4

Vcc

Vee

Vbb7

6

R3887ohm

R4499ohm

5.5VVCC R5402ohm

R6

1kohm

R7249ohm

5.5VVCC

R8150ohm

R9249ohm

R10150ohm

C2

220pF

R11

10ohm

C3

1000pF

R124.99kohm

R13499ohm

5.5VVCC

Q1NE46134

R1468ohm

R1568ohm

C4

220pF

Q2

MRF5583

5.5VVCC 5.5VVCC

C5

220pF

R161kohm

R174.99kohm

5.5VVCC

Q3NE46134

D1

DIODE_VIRTUAL

R1850ohm

5.5VVCC

LED1

50%

50kOhmKey = a

R19

5.5VVCC

R20

10kohm

Q4FMMT491

C60.1uF

5.5VVCC

R21

1kohm

Q5FMMT491

5.5VVCC

C70.1uF

R22100ohm

C81uF

C90.1uF

A1AD558

+

-

D0 D1 D2 D3 D4 D5 D6 D7

VDAC

LSB

LSB+1

LSB+2

LSB+3

LSB+4

LSB+5

LSB+6

MSB

Chip Select

Chip Enable

DAC Out

DAC Out

Divider Out

LED Connection

Copper tube shield, connected to the cable braid

(not grounded)

Copper tube shield, connected to the cable braid

(not grounded)

HB LED Pulser Board Prototype

LED Pulser Signal at Different DAC Settings(measured with a PMT and an optical filter)

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

1.0E-07 1.5E-07 2.0E-07 2.5E-07 3.0E-07 3.5E-07

Time (s)

Vo

lta

ge

(a

t 50

oh

m)

Ped000

Ped064

Ped128

Ped192

Ped224

Ped240

Ped255

HB LED Pulser Board Prototype output signal integral

profile at different amplitudes LED Pulser Signal Integral

0%

20%

40%

60%

80%

100%

1.0E-07 1.5E-07 2.0E-07 2.5E-07 3.0E-07 3.5E-07 4.0E-07

Time (s)

Sig

nal

In

teg

ral

Ped000

Ped064

Ped128

Ped192

Ped224

Ped240

Ped255

LED Pulser Board prototype output signal dynamic range.

HB LED Pulser Board prototype LED signal integral for different pulse voltages (measured with a PMT)

1.E-13

1.E-12

1.E-11

1.E-10

1.E-09

0 1 2 3 4 5 6

Pulse Voltage (V)

Sig

nal

In

teg

ral

(C)

Charge

HB LED Pulser Boards Production

• Design, manufacture, quality control and delivery done by The University of Iowa.

• 30 LED Pulser Boards delivered to FNAL ASAP, on August 2004.

• 110 LED Pulser Boards were tested at the University of Iowa and delivered to FNAL in Sept. 2004.

• The Pulser Boards are o.k. and give enough signal.

HB LED Pulser Boards Production