GX3540 – 40 Channel ECL I/O Expansion Board

The GX3540 consists of 20 differential ECL drivers and 20 differential ECL receivers.  Each channel can be accessed via software commands for use in static I/O applications.  The board includes on-board terminators for each differential channel. The GX3640 model is used when ordering the GX3500 with the GX3540.

GX3540 Termination Resistors and Voltage Sources

The board is supplied with 510-ohm terminators that are terminated to –5.2 volts.  Optionally, the board can be configured to use terminations with an onboard 2-volt termination voltage source.  The terminating resistors are socketed, allowing the user to change the termination resistors and voltage sources for specific applications.

To change the termination voltage sources and termination resistors, remove the five resistor nets attached to the GX3540 expansion board (positions J1-J5).  J1-J5 resistor sockets have eleven plugs and the provided resistor nets have ten pins.  Pin 1 of the resistor net should go into the appropriate hole on the socket depending on the target termination voltage source.  The GX3540 PCB is marked with –2.0V on one side and –5.2 V on the other.  51-ohm resistor nets and 510-ohm resistor nets are provided with the GX3540.  When using the –2-volt source, a minimum of 49-ohm resistance is required and when using the –5.2-volt source, a minimum of 390-ohm resistance is required.

GX3540 Connectors

Connections to the GX3540 may be made with 68-pin VHDCI male plug connector. Shielded cables with matching connectors are available from Marvin Test Solutions.

GX3540 J1 – Flex I/O Bank A Inputs Connector

Pin #
Function
Pin #
Function
Pin #
Function
Pin #
Function
1
GND
18
GND
35
ECL In 0+
52
ECL In 8-
2
GND
19
GND
36
ECL In 0-
53
ECL In 9+
3
GND
20
GND
37
ECL In 1+
54
ECL In 9-
4
GND
21
GND
38
ECL In 1-
55
ECL In 10+
5
GND
22
GND
39
ECL In 2+
56
ECL In 10-
6
GND
23
GND
40
ECL In 2-
57
ECL In 11+
7
GND
24
GND
41
ECL In 3+
58
ECL In 11-
8
GND
25
GND
42
ECL In 3-
59
ECL In 12+
9
GND
26
GND
43
ECL In 4+
60
ECL In 12-
10
GND
27
Reseverd
44
ECL In 4-
61
ECL In 13+
11
GND
28
Reserved
45
ECL In 5+
62
ECL In 13-
12
GND
29
I/O 14+
46
ECL In 5-
63
ECL In 14-
13
GND
30
I/O 15+
47
ECL In 6+
64
ECL In 15-
14
GND
31
I/O 16+
48
ECL In 6-
65
ECL In 16-
15
GND
32
I/O 17+
49
ECL In 7+
66
ECL In 17-
16
GND
33
I/O 18+
50
ECL In 7-
67
ECL In 18-
17
GND
34
I/O 19+
51
ECL In 8+
68
ECL In 19-

GX3540 J1 Flex IO Bank A Inputs Connector

GX3540 J2 – Flex I/O Bank D Outputs Connector

Pin #
Function
Pin #
Function
Pin #
Function
Pin #
Function
1
GND
18
GND
35
ECL In 0+
52
ECL In 8-
2
GND
19
GND
36
ECL In 0-
53
ECL In 9+
3
GND
20
GND
37
ECL In 1+
54
ECL In 9-
4
GND
21
GND
38
ECL In 1-
55
ECL In 10+
5
GND
22
GND
39
ECL In 2+
56
ECL In 10-
6
GND
23
GND
40
ECL In 2-
57
ECL In 11+
7
GND
24
GND
41
ECL In 3+
58
ECL In 11-
8
GND
25
GND
42
ECL In 3-
59
ECL In 12+
9
GND
26
GND
43
ECL In 4+
60
ECL In 12-
10
GND
27
Reseverd
44
ECL In 4-
61
ECL In 13+
11
GND
28
Reserved
45
ECL In 5+
62
ECL In 13-
12
GND
29
ECL Out 14+
46
ECL In 5-
63
ECL In 14-
13
GND
30
ECL Out 15+
47
ECL In 6+
64
ECL In 15-
14
GND
31
ECL Out 15+
48
ECL In 6-
65
ECL In 16-
15
GND
32
ECL Out 15+
49
ECL In 7+
66
ECL In 17-
16
GND
33
ECL Out 15+
50
ECL In 7-
67
ECL In 18-
17
GND
34
I/O 19+
51
ECL In 8+
68
ECL In 19-

GX3640 J2 Flex IO Bank D Output Connector

GX3540 Programming

Use the GXFPGA driver GxFpgaPioxxx functions to program the GX3540. Before using a GxFpgaPioxxx function, check the function reference to ensure the function applies to the GX3540.  The functions are described in detail in FunctionReference. Some of the functions are also available from the software front panel.

GX3540 Specification

Number of Channels
20 differential inputs.
20 differential outputs.
Logic Family
MECL 10K compatible.
Driver Output VOH
-0.98V (Min.)
-0.81V (Max.)
Driver Output VOL
-1.95V (Min.)
-1.63V (Max.)
Receiver Input VIH
-1.13V (Min.)
-0.81V (Max.)
Receiver Input VIL
-1.95V (Min.)
-1.48V (Max.)
Receiver Differential Input Level
150mV (typ.)
1.0V (Max.)
Receiver Common Mode Range
-2.85V (Min.)
+0.3V (Max.)
Maximum Absolute Input Voltage Range
0 to -5.2V.
ECL I/O Terminations
Each input and output is terminated with a 390-ohm resistor which is connected to -5.2V. Optionally, the board can be configured to use terminations with an onboard -2V termination voltage source.
I/O Connectors
(2) SCSI III, VDHCI type, 68 pin female
One for ECL outputs, one for ECL inputs.