Section 5 Using Substrate Bias; Introduction; Substrate Bias Instrument Connections; Figure 5-1. Tsp-Link Connections For Two Instruments - Keithley Series 2600 Application Manual

5.1 Introduction

To this point in this guide, we have focused on performing tests on
devices that do not require substrate bias . Because many devices,
especially those in complex packages, do require some form of
substrate bias, our discussion would not be complete without dis-
cussing methods for applying and programming substrate bias .
In the following paragraphs, we will discuss applying substrate bias
by adding another Series 2600 System SourceMeter instrument .
5.2 Substrate Bias Instrument
Connections
WARNING
Interlock circuits must be connected before use.
Connect the fixture ground to safety earth ground
using #18 AWG minimum wire before use. Turn off
all power before connecting or disconnecting wires
or cables.
5.2.1 Source-Measure Unit Substrate
Bias Connections and Setup
Figure 5-1 shows test connections when using two Series 2600
System SourceMeter instruments because the tests outlined in the
following sections require three SMUs . Two SMUs supply the same
functions as outlined earlier in this guide, and a third SMU is used
to apply substrate bias . In the past, this would have required con-
necting and coordinating three separate instruments, each with
only one SMU .
To simplify hardware integration, the Keithley Series 2600 System
SourceMeter instruments are equipped with a few features that
make the task of multi-channel testing much easier . For example,
we can use a dual-channel instrument such as the Keithley Model
2602, 2612, or 2636 and a single-channel Instrument such as the
Model 2601, 2611, or 2635 . Therefore, we need only two instru-
ments to perform the test . All of the following programs will also
work using two dual-channel instruments with no modification .
For instrument-to-instrument communication, Keithley's Series
2600 System SourceMeter instruments employ an expansion
Section 5
Using Substrate Bias
interface known as TSP-Link™ interface . TSP-Link allows expanding
test systems to include up to 16 TSP-Link enabled instruments .
In a TSP-Link-enabled system, one of the nodes (instruments) is
the master, which is generally denoted as Node 1, while the other
nodes in the system are slaves . One GPIB connection is required
to link the controlling PC and the master instrument . All other
master/slave connections require a simple TSP-Link connection
using a crossover Ethernet cable . Additional instruments can
be connected as slaves by simply connecting each slave to one
another serially using additional crossover Ethernet cables and
configuring each instrument for use as a TSP-Link node .
More information on TSP-Link features can be found in the Series
2600 System SourceMeter Reference Manual .

Figure 5-1. TSP-Link connections for two instruments

GPIB Cable
TSP-Link Cable
CPU with
GPIB
Series 2600
System
SourceMeter
Node 1: Master
Series 2600
System
SourceMeter
Node 2: Slave
5-1