Endcap Muon meeting: UC Davis, Feb. 25-26, 2005 J. Hauser UCLA 1 TMB and RAT Status Report Outline: Current status of TMB and RAT boards Noise measurements.

1Endcap Muon meeting: UC Davis, Feb. 25-26, 2005 J. Hauser UCLA

TMB and RAT Status Report

Outline:• Current status of TMB and RAT boards• Noise measurements• Design and layout changes• Production plan


TMB and RAT Current Status• Parts for full production of 516 boards are in hand• Made 29 working sets (TMB-base, RAT) • Made 40 X2V4000 mezzanine cards• Noise problems in ALCT data transmission through

RAT found at test beam and in bench tests:• Too few grounds for 80 MHz RATTMB data transmission

• Cross-talk between signals on RAT and perhaps TMB as well (M. Johnson)

• Prototype of revised RAT board and testing backplane done, noise greatly reduced

• Layout of revised TMB board well underway


Recall: TMB2004 Logic 1 on RAT2004Logic 1

Clock off

Logic 1

Clock ON

Logic 1

Clock ON &

ALCT 1 MHz

!


LVTTL (from +3.3v) Logic Levels• Typical outputs 0.4v low, 2.4v high, transition ~1.5v• Worst case output supposed to be 0.8v low, 2.0v high• Measurements showed violation of that:


Remedies• Make the grounding for RAT like any other

board in the peripheral crate:• Add one ground pin on every row of RAT pins. 651 ground

pins.

• Add backplane ground connections

• Requires more total pins:• Replace 55-pin X3 and 125-pin X18 connectors by two 110-

pin Type-A connectors

• 40 more pins, all “C” column pins used for grounding

• Also more robust alignment pins (noticed RAT alignment pins already broken before Sept beam test)

• Reduce crosstalk between long traces:• Space them further apart

• Change order of board layers to put traces next to ground plane


“Halfway Test” of Noise Reduction• RAT2005 board layout and new test

backplane

• Many ground connections to backplane, but uses existing TMB2004 board• Eliminates large inductive loops on RAT side and

greatly reduces cross-talk between traces on RAT side.

• Doesn’t eliminate large inductive loops or reduce cross-talk between traces on TMB side.

• Naïve expectation: reduce noise level up to ~factor 4:– x2 due to inductive loops

– maybe x2 more if cross-talk on RAT is also important


RAT2005 Changes• RAT2005 design changes:

• On-board 1.8v regulator for Spartan-3 core voltage:– Previously on TMB, this eliminates transmission noise

• Change buffer ICs from high-drive to balanced light-drive devices:– Reduces ground bounce from signal transitions

– Reduces inductive effects with slower edge speeds

• Additional filter capacitors

• RAT2005 layout changes:• New connector layout

• Increase trace-to-trace separation for 80 MHz buses


“Half-way Test” Peak-to-Peak Noise

0

1

2

3

4

5

6

7

8

9

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500

RAT2004 Pk-Pk Noise (mV)

Num

ber o

f Sig

nals

0

5

10

15

20

25

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500


Num

ber o

f Sig

nals

0

200

400

600

800

1000

1200

0 200 400 600 800 1000 1200


RAT2

005 P

k-Pk N

oise (

mV)

RAT2004Mean=434 mV

RAT2005

Mean=124 mV

(Reduction factor 3.5)

Little correlation (signal positions have changed)


TMB2005 Changes• TMB2005 design changes (done):

• Change buffer ICs from high-drive to balanced light-drive devices

• Delete legacy ALCT cable receiver ICs (removes “T” structures on circuit traces)

• +3.3v for RAT comes from TMB power plane instead of a separate circuit.

• Additional filter capacitors by driver ICs

• Replace 1.5v regulator with more stable type

• ALCT clock continues during hard reset (bug fix)

• TMB2005 layout changes:• New connector layout

• Increase trace-to-trace separation for 80 MHz buses


Current Layout Screen-Cap


Status of TMB2005 Layout•Over last 5 weeks:

• Creation of footprints done

• Component placement done

• Routing done for most major sections

•Expect 5 more weeks of layout

Section Done Not Done

CFEB √

DMB √

ALCT √

CCB ~√

MPC √

RPC √

VME √

JTAG √

Clock √

Power √

Mezz. conn. √

Test points √


TMB/RAT Production Plan• 468+10%=515 boards each type• Agreed delivery schedule (Dec. 17):

• 10 pairs in May (preproduction)• 30 (total) by end of July• 150 by end of August• 270 by end of September• 390 by end of October• 510 by end of November• 540 by end of December

• Requirements:• Layout done by April 1• (10) Proto. boards by April 21• 3 or 4 weeks for testing 10 pairs• Then place large PCB and assembly orders to companies• Summer mass testing will need lots of students


Virtex-2 Mezz Cards• Principle: keep well ahead of TMB schedule• All parts in hand• First 100:

• 40 cards already assembled (no changes)

• +60 cards being assembled, arrive April 1

• Thereafter 3 cycles:• 1 month for assembly and 1 month for testing

• +120 arrive June 1 (total 220)

• +120 arrive Aug. 1 (total 340)

• +180 arrive Oct. 1 (total 520)

Endcap Muon meeting: UC Davis, Feb. 25-26, 2005 J. Hauser UCLA 1 TMB and RAT Status Report Outline: Current status of TMB and RAT boards Noise measurements.

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