CMS Muon Endcap ALCT Delay chips D16G Mass Production Test and Delivery

Introduction.

The 16 channel delay chips D16G ( Ref. 1) provide programmable time delay of the ALCT ( Ref. 2) input signals coming from the CMS muon endcap CSC anode front end boards. Here we present the status and results of the mass production test of these chips. The status of chips delivery to UCLA for ALCT boards assembly is given as well. This page helps to monitor the performance of the delay chips. It also provides information needed for the tuning parameters of the chips installed on the ALCT board. The parameters of the chip were measured at Uc=0 mV.

Description of the distributions of the delay chip parameters in Fig. 1 (before applying selection cuts) given in Table 1 is here. The cuts are shown as red lines.For chips from trays 1-16 we used cuts from Cut List #4 and starting from tray 17 - Cut List #5. Also, starting from tray 17, the data have been analyzing online on the delay chips test stand. The chips that passed the selection cuts have parameters distributions given in Fig.2. The overall status of the test presented in Fig.3.

Due to spread of the parameters the delay chips were divided on 9 groups having each 2 ns wide bin in the averaged over chip delay(code=15) distribution (Page 5 in Fig.2). As an example for the chips from trays 1-16 the list of the groups is given here. In this list D0 is the averaged over all chips in the group delay at code 0, delay(0), D15 - the same for delay(15). SLP is the slope as (D15-D0)/15, MxD is the maximum absolute deviation of the delay in the group from predicted delay defined as D0 + Code*SLP where the Code is the delay code (0-15). MxW is the maximum width of the road (delays of all channels from all chips in the group at given delay code) over all delay codes. All delays are absolute delays in the chips (the test stand delays were subtracted). The chips from groups with numbers less than 8 can be tuned on the ALCT board after assembling to get the same average delay at code of 15 as in group #8. Increasing the Uc voltage by 50 mV raises D15 by 0.8-1.1 ns. The chips from groups 1,2 and 9 (of total about 10%) will not be used for installation on the ALCT boards. Table 2 presents the distributions of the parameters for each group.

The total number available for the test chips was 23,515 (trays 1-149). They were tested in the first pass. Chips in tray 150 and beyond are the chips which failed in the first pass and have been remeasured.

The time stability of the delay chips test stand is shown in Table 3. The first page has the plots of relative changes in the averaged for each tray chip delays at the delay code of 0 (in slot 1 and 2). The second page shows stability of residuals for each channel.

Table 4 is monitoring the delivery schedule of the chips from each group.

Table 1. Status and results of the test.

Date	Tray ##	Before cuts	After cuts	Test status	Chips tested	Passed the cuts	Yield, %
11/01/2001 - 07/10/2002	1 - 154	Fig. 1*	Fig. 2	Fig. 3*	23515*	20405	87%

* - does not include remeasured chips, trays 150-154

Table 2. Group distributions (Fig.).

Group #	1	2	3	4	5	6	7	8	9
Fig. #	1	2	3	4	5	6	7	8	9
Quantity	428	659	1273	1863	2261	3118	6297	3948	556
Yield, %	1.8%	2.8%	5.4%	7.9%	9.6%	13.3%	26.8%	16.8%	2.4%

The uniformity of the channels within each certified chip.

The channel uniformity is shown using the channel residual which is defined as the difference between the channel parameter and its value averaged over the 16 channels of each chip, see it in ( Uniformity ). It is one and the same for all groups.

Table 3. Time stability of the test (by trays).

Date	Tray ##	Plot
11/01/2001 - 07/05/2002	1 - 149	Fig.

Table 4. Delivery to the UCLA (for the ALCT assembly) and other sites.

Site	Shipment	Date	Number of chips,total	Group 5	Group 6	Group 7	Group 8	Group 9
UCLA	1	11/14/2001	1120		320	480	320
	2	02/22/2002	960			640	320
	3	05/01/2002	5760	960	960	2880	960
	4	06/06/2002	3840	960	960	960	960
	5	07/15/2002	4258	335	923	1498	1502
	6	11/11/2004	479					479
	Total*		16417	2255	3163	6458	4062	479
TOTEM	1	10/28/2003	87					87
	Total*		87					87
Total			16504	2255	3163	6458	4062	566

* - Groups 6-9 have more chips than given in Table 2 because the files with data for the corresponding balance of chips (about 1.5 % of the total) were not provided by the delay test stand for the presentation in Table 2. Also contradiction with Table 2 for group #5 remains unexplained. The final numbers (see total and table 5 below) are:

23716 - total number of tested chips.

20811 - total number of certified chips (corresponding yield is 88%).

Table 5. Group distributions (final numbers)

Group #	1	2	3	4	5	6	7	8	9	Total
Quantity	452	680	1280	1895	2255	3163	6458	4062	566	20811

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Last modified: Thu Nov. 11 12:30:00 CST 2004