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Hardware Features

2.2

External Connections

2.2.1

Power Supply

The power-supply connections for the EVM are located on the TB1 terminal block. The valid power-

supply range is +7 V to +44 V. The supplie is decoupled with a 10-µF tantalum capacitor, as well as a

1-µF ceramic capacitor near the device. The XTR111EVM also contains test points for the supply

voltage and ground located next to TB1.

2.2.2

Signal Input

Terminal block TB4 is used for the noninverting signal input, VIN. The valid range is from 0 V to +12 V.

A test point connected to VIN is located next to TB4.

2.2.3

Voltage Regulator

The XTR111 provides an externally-adjustable voltage regulator that can provide up to 5 mA of

current. The regulator has drive (REGF) and sense (REGS) inputs. Sense input REGS is referenced to

3 V, representing the lowest adjustable voltage level. An external resistor divider sets the drive input,

REGF. For the XTR111EVM, REGF is set to 5 V. REGF (named VREG on the XTR111EVM), is

accessible through terminal block TB3 and by a test point labeled VREG.

2.2.4

Output

The XTR111 is designed for use with a discrete p-channel MOSFET (Q3). This FET extends the

voltage compliance for the controlled current to a potential well below the negative supply voltage. The

current output for the XTR111EVM is located at terminal block TB2. A test point connected to IOUT is

located next to TB2. The XTR111EVM can be configured for a voltage output by shunting J2. There

are two test points connected to the voltage output circuit. The VOUT test point is placed directly at the

node of the resistive load, and VOUT_F provides a basic filter for the output.

2.2.5

Additional Test Points

The following list shows additonal test points:

•

OD is connected to the output disable pin of the XTR111. To disable the output, pull the OD pin high

by shunting J1.

•

EF is connected to the error flag pin of the XTR111. The EF pin is active low. When there is an error,

EF is pulled low and the LED circuit is enabled.

2.3

Jumper Configuration Settings

Jumper configurations for the XTR111EVM are shown in Section 3

Table 2. XTR111EVM Jumper Settings

Jumper

Function

J1

Connects OD to the onboard 5-V supply, disabling the output.

J2

Configures the current output to a voltage output.

J3

Applies a 4-mA input signal shift.

3

SBOU048C – April 2007 – Revised April 2013

XTR111 Demonstration Fixture User's Guide

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