National Semiconductor DS91M125 User manual

August 11, 2008
Rev. 1.0 © 2008, National Semiconductor Corp.
1
DS91M125
125 MHz 1:4 M-LVDS Repeater with
LVDS Input Evaluation Kit
USER MANUAL
Part Number: DS91M125EVK NOPB
For the latest documents concerning these products and evaluation kit, visit lvds.national.com. Schematics and
gerber files are also available at lvds.national.com

August 11, 2008
Rev. 1.0 © 2008, National Semiconductor Corp.
2
Overview
The purpose of this document is to familiarize you with the DS91M125 evaluation board, suggest the test setup
procedures and instrumentation, and to guide you through some typical measurements that will demonstrate the
performance of the device. The board enables the user to examine performance and all functions of the
DS91M125 as a standalone device.
The DS91M125 is a high-speed 1:4 M-LVDS repeater with an LVDS input designed for multipoint applications
with multiple drivers or receivers. The device conforms to TIA/EIA-899 standard. It utilizes M-LVDS technology
for low power, high-speed and superior noise immunity.
Description
Figure 1 below represents the top layer drawing of the board with the silkscreen annotations. It is a 2.5 x 3 inch
4 layer printed circuit board (PCB) that features a single DS91M125 (U2) device.
Figure 1 - DS91M125EVK Top View Drawing

August 11, 2008
Rev. 1.0 © 2008, National Semiconductor Corp.
3
DS91M125 Evaluation in a Point-to-Point Link
The following is a recommended procedure for using and evaluating the DS91M125EVK. Figure 2 depicts a
typical setup and instrumentation used.
1. Select a single DS91M125 evaluation board.
2. Apply the power to the board (3.3 V typical) between J3 and J4 power tabs, observe the value of ICC,
and compare it with the expected value (refer to the datasheet) to ensure that the devices are
functional.
3. Enable one of the U2 driver outputs. This is accomplished by setting the DE0-3 pin to VDD (JP3-6).
4. Connect a signal source to the driver input (DI+, DI-). The signal needs to be an LVDS/M-
LVDS/CML/LVPECL compliant signal. Refer to the DS91M125 datasheet for the receiver input
compatibility.
5. Connect one of the U2 outputs (A0-3/B0-3) to an oscilloscope and observe the waveforms.
Figure 2 – DS91M125 Test Setup

August 11, 2008
Rev. 1.0 © 2008, National Semiconductor Corp.
4
Figure 3 shows an eye diagram acquired at the output of the DS91M125 driver loaded with a 100-ohm resistor.
The generator connected to the driver input simulated a 100 Mbps PRBS-7 NRZ.
Figure 3 – DS91M125 Output

Item Part Type Part Number/Value Mfg Description Qty
SMTNoSub
Ref Des Notes
Rev
1 PCB P-06540R0 ENERCON 1 0
2
3 SUBASY Z3211-04 ENERCON LABEL, MADE IN U.S.A. 1 1
Apply t b tt m
f PCBA
4
5 IC DS91M125TMA NAT 125MHz 1:4 M-LVDS Repeater, SOIC16 1 X 0U2
6
7 RES ERJ-2RKF1000 PANA 100 Ohm 1/16W ±1% 0402 100ppm, Pb-Free 1 X 0R13
8
9 CAP 06035C103KAT AVX .01µF, 50V, ±10%, 0603, Ceramic, X7R,
Pb-Free 2 X 0C7,10
10 CAP 0603YC104KAT AVX .1µF, 16V, ±10%, 0603, Ceramic, X7R, Pb-
Free 2 X 0C5,9
11 CAP TAJA106K016 AVX 10µF, 16V, ±10%, A-Case, Tantalum, Pb-
Free 1 X 0C8
12
13 CONN 1287 KEYSTONE Fast n, Male, .250", Pb-Free 2 0J3,4
14 CONN 142-0701-851 EMERSON SMA, Jack Receptacle, 50 OHM, Pb-Free 10 0SMA13-22
15 CONN 15-29-1024 MOLEX Jumper Shunt, 2p, G ld, Pb-Free 4 0
Use n JP3,4,5,6
Pins 2&3
16 CONN TSW-103-07-G-S SAMTEC Header, 3p, Male, .100"sp, G ld, Pb-Free 4 0JP3,4,5,6
17
18 STENCL T-06544R0 ENERCON STENCIL FABRICATION, BOTTOM,
DS91M047EVK/DS91M1... 1
0
19
20 REF C-06541R0 ENERCON FAB DWG,
DS91M047EVK/DS91M124EVK/DS91M125EVK
0
21 REF C-06542R0 ENERCON PALLET DWG,
DS91M047EVK/DS91M124EVK/DS91M125EVK
0
22 REF S-06539R0 ENERCON SCHEMATIC,
DS91M047EVK/DS91M124EVK/DS91M125EVK
0
23
10:32:55 AM, 06/17/08 1 2
Page
of
Confidential and Proprietary. T is document is considered uncontrolled unless stamped ot erwise.
Creation Date:
03/14/08
Responsible Eng/Mgr: Creator:
Arlene Fox
PL Number:
Z3252-01
Rev:
1
Rev Date:
04/30/08
PL Status:
Released
Rev By:
BJ
Main Product:
PCBA, DS91 125EVK, ROHS
I LE: NATI NAL SEMIC NDUCT R
PCBA, DS91M125EVK, R HS
DS91M125
ENERCON - BILL OF MATERIALS

Notes:
DO NOT STUFF:
U1
1-10
JP1,2
R1-12,14,15
T1-2,7,15,17,19,21,23,3,11,12,16,18,20,22,24
J1,2
C1,2,3,4,6
S A1-12
10:32:55 AM, 06/17/08 2 2
Page
of
Confidential and Proprietary. T is document is considered uncontrolled unless stamped ot erwise.
Creation Date:
03/14/08
Responsible Eng/Mgr: Creator:
Arlene Fox
PL Number:
Z3252-01
Rev:
1
Rev Date:
04/30/08
PL Status:
Released
Rev By:
BJ
Main Product:
PCBA, DS91 125EVK, ROHS
I LE: NATI NAL SEMIC NDUCT R
PCBA, DS91M125EVK, R HS
DS91M125
ENERCON - BILL OF MATERIALS