TEXAS INSTRUMENTS XTR117 Technical data

SBOS344B − SEPTEMBER 2005 − REVISED JANUARY 2006

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments

4-20mA Current-Loop Transmitter

XTR117

FEATURES

D LOW QUIESCENT CURRENT: 130µA
D 5V REGULATOR FOR EXTERNAL CIRCUITS
D LOW SPAN ERROR: 0.05%
D LOW NONLINEARITY ERROR: 0.003%
D WIDE-LOOP SUPPLY RANGE: 7.5V to 40V
D MSOP-8 AND DFN-8 PACKAGES

APPLICATIONS

D TWO-WIRE, 4-20mA CURRENT LOOP

TRANSMITTER

D SMART TRANSMITTER
D INDUSTRIAL PROCESS CONTROL
D TEST SYSTEMS
D CURRENT AMPLIFIER
D VOLTAGE-TO-CURRENT AMPLIFIER

DESCRIPTION

The XTR1 17 i s a p recision current o utput c onverter d esigned
to transmit analog 4-20mA s ignals over a n industry-standard
current loop. It provides accurate current scaling and output
current limit functions.

The on-chip vol tage regulator (5V) can be us ed to power
external circuitry. A current return pin (I
current used in external circuitry to assure an accurate
control of the output current.

The XTR117 is a fundamental building block of smart
sensors using 4-20mA current transmission. The XTR117 is
specified for operation over the extended industrial
temperature range, −40°C to +125°C.

RELATED 4-20mA PRODUCTS

XTR115 5V regulator output and 2.5V reference output
XTR116 5V regulator output and 4.096V reference output

NOTE:For 4-20mA complete bridge and RTO conditioner solutions,

see the XTR product family website at www.ti.com.

) senses any

RET

XTR117

V

REG

8

R

IN

I

IN

2

V

IN

I

RET

3

semiconductor products and disclaimers thereto appears at the end of this data sheet.

All trademarks are the property of their respective owners.

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R

1

2.475k

A1

Ω

+5V

Regulator

www.ti.com

R
25

R

2

Ω

LIM

V+

7

B

6

E

5

IO= 100 V

4

Q1

R

IN

I

O

V

LOOP

R

L

IN

Copyright  2005−2006, Texas Instruments Incorporated

"##$

XTR117

MSOP-8

DGK

BOZ

XTR117

DFN-8

DRB

BOY

SBOS344B − SEPTEMBER 2005 − REVISED JANUARY 2006

www.ti.com

ABSOLUTE MAXIMUM RATINGS

(1)

Power Supply, V+ (referenced to IO pin) +50V. . . . . . . . . . . . . . . .

Input Voltage, (referenced to I

pin) 0V to V+. . . . . . . . . . . . . . . .

RET

Output Current Limit Continuous. . . . . . . . . . . . . . . . . . . . . . . . . . . .

V

, Short-Circuit Continuous. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

REG

ELECTROSTATIC DISCHARGE SENSITIVITY

This integrated circuit can be damaged by ESD. Texas
Instruments recommends that all integrated circuits be
handled with appropriate precautions. Failure to observe

proper handling and installation procedures can cause damage.

Operating Temperature Range −55°C to +125°C. . . . . . . . . . . . . . .

Storage Temperature Range −55°C to +125°C. . . . . . . . . . . . . . . . .

Junction Temperature +165°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ESD Rating (Human Body Model) 2000V. . . . . . . . . . . . . . . . . . . . . . .

(Charged Device Model) 1000V. . . . . . . . . . . . . . . . .

(1)

Stresses above these ratings may cause permanent damage.

ESD damage can range from subtle performance degradation to
complete device failure. Precision integrated circuits may be more
susceptible t o damage because very small parametric changes could
cause the device not to meet its published specifications.

Exposure to absolute maximum conditions for extended periods
may degrade device reliability. These are stress ratings only , an d
functional operation of the device at these or any other conditions
beyond those specified is not implied.

PACKAGE/ORDERING INFORMATION

(1)

PRODUCT PACKAGE-LEAD PACKAGE DESIGNATOR PACKAGE MARKING

(1)

For the most current package and ordering information see the Package Option Addendum at the end of this document, or see the TI web site
at www .ti.com.

PIN ASSIGNMENTS

Top View

NC

I

RET

XTR117 XTR117

(1)

1

I

2

IN

3

I

4

O

NOTES: (1) NC = No connection. Leave unconnected on PCB.

(2)Connect thermaldie padto I

8

7

6

5

V

REG

V+

B(Base)

E(Emitter)

RET

(1)

1

NC

I

IN

I

RET

I

O

or leave unconnected on PCB.

2

3

4

Exposed

Thermal
Die Pad

on

Underside

DFN−8MSOP−8

8

V

REG

V+

7

B(Base)

6

(2)

E (Emitter)

5

2

"##$

www.ti.com

SBOS344B − SEPTEMBER 2005 − REVISED JANUARY 2006

ELECTRICAL CHARACTERISTICS: V+ = +24V

Boldface limits apply over the temperature range, TA = −40°C to +125°C.

All specifications at TA = +25°C, V+ = 24V, RIN = 20kΩ, and TIP29C external transistor, unless otherwise noted.

PARAMETER CONDITION

MIN TYP MAX

OUTPUT

Output Current Equation I

O

Output Current, Linear Range 0.20 25 mA

Over-Scale Limit I
Under-Scale Limit I

LIM
MIN

I

= 0 0.13 0.20 mA

REG

SPAN

Span (Current Gain) S 100 A/A

(1)

Error

IO = 200µA to 25mA ±0.05 ±0.4 %

vs Temperature TA = −40°C to +125°C ±3 ±20 ppm/°C

Nonlinearity IO = 200µA to 25mA ±0.003 ±0.02 %

INPUT

Offset Voltage (Op Amp) V

OS

IIN = 40µA ±100 ±500 µV

vs Temperature TA = −40°C to +125°C ±0.7 ±6 µV/°C

vs Supply Voltage, V+ V+ = 7.5V to 40V +0.1 +2 µV/V

Bias Current I

B

vs Temperature TA = −40°C to +125°C 150 pA/°C

Noise: 0.1Hz to 10Hz e

n

DYNAMIC RESPONSE

Small-Signal Bandwidth C

= 0, RL = 0 380 kHz

LOOP

Slew Rate 3.2 mA/µs

(2)

V

REG

Voltage 5 V
Voltage Accuracy I

= 0 ±0.05 ±0.1 V

REG

vs Temperature TA = −40°C to +125°C ±0.1 mV/°C

vs Supply Voltage, V+ V+ = 7.5V to 40V 1 mV/V
vs Output Current See Typical Characteristics

Short-Circuit Current 12 mA

POWER SUPPL Y

Specified Voltage Range V+ +24 V
Operating Voltage Range +7.5 +40 V
Quiescent Current I

Q

Over Temperature TA = −40°C to +125°C 250 µA

TEMPERATURE RANGE

Specified Range −40 +125 °C
Operating Range −55 +125 °C
Storage Range −55 +150 °C
Thermal Resistance q

JA

MSOP 150 °C/W
DFN 53 °C/W

(1)

Does not include initial error or temperature coefficient of R

(2)

Voltage measured with respect to I

RET

pin.

.

IN

XTR117

I

= I

x 100

O

IN

32 mA

−35 nA

0.6 µV

130 200 µA

UNITS

PP

3

"##$

SBOS344B − SEPTEMBER 2005 − REVISED JANUARY 2006

TYPICAL CHARACTERISTICS: V+ = +2.7V to +5.5V

At TA = +25°C, V+ = 24V, RIN = 20kΩ, and TIP29C external transistor, unless otherwise noted.

www.ti.com

45

CURRENT GAIN vs FREQUENCY

40

30

Gain (dB)

20

10

10k 100k

OVER−SCALE CURRENT vs TEMPERATURE

34

With External Transistor

33

32

V+ = 36V

31

30

Over−Scale Current (mA)

29

V+ = 24V

28

−75−

50−250 255075100

C

OUT

R

Frequency (Hz)

V+ = 7.5V

Temperature (_C)

=250

L

= 10nF

Ω

180

QUIESCENT CURRENT vs TEMPERATURE

170
160

A)

µ

150

C

=0

OUT

Ω

=0

R

L

140
130
120
110

Quiescent Current (

100

90

V+=36V

V+ = 24V

V+ = 7.5V

80

1M

−75−

50−250255075100

125

Temperature (_C)

VOLTAGEvs V

V

−55_

REG

C

Sourcing

Current

5.5
+125_C

5.0

Voltage (V)

+25_C

REG

V

Sinking
Current

CURRENT

REG

+25_C

−55_

+125_C

C

4.5

125

−

101 2 3

Current (mA)

I

REG

4

SPAN ERROR vs TEMPERATURE

OFFSET VOLTAGE DISTRIBUTION

50
40
30
20
10

0

Population

500−450−400−350−300−250−200−150−100

−

0

50

50

−

100

Offset Voltage (µV)

150

200

250

300

350

400

450

500

Span Error (m%)

−

10

−

20

−

30

−

40

−

50

−75−

50−250255075100

Temperature(_C)

125

4

www.ti.com

"##$

SBOS344B − SEPTEMBER 2005 − REVISED JANUARY 2006

APPLICATIONS INFORMATION

BASIC OPERATION

The XTR117 is a precision current output converter
designed to transmit analog 4-20mA signals over an
industry-standard current loop. Figure 1 shows basic
circuit connections with representative simplified input
circuitry. The XTR117 is a two-wire current transmitter.
Its input current (pin 2) controls the output current. A
portion of the output current flows into the V+ power
supply, pin 7. The remaining current flows in Q1.
External input circuitry connected to the XTR1 17 can be
powered from V
terminals must be returned to I
a local ground for input circuitry driving the XTR117.

The XTR117 is a current-input device with a gain of 100.
A current flowing into pin 2 produces IO = 100 x IIN. The
input voltage at the IIN pin is zero (referred to the I
pin). A voltage input is converted to an input current with
an external input resistor, RIN, as shown in Figure 1.
Typical full-scale input voltages range from 1V and
upward. Full-scale inputs greater than 0.5V are
recommend to minimize the ef fects of offset voltage and
drift of A1.

. Current drawn from these

REG

, pin 3. The I

RET

RET

pin is

RET

EXTERNAL TRANSISTOR

The external transistor, Q1, conducts the majority of the
full-scale output current. Power dissipation in this
transistor can approach 0.8W with high loop voltage
(40V) and 20mA output current. The XTR117 is
designed to use an external transistor to avoid on-chip,
thermal-induced errors. Heat produced by Q1 will still
cause ambient temperature changes that can influence
the XTR117 performance. To minimize these effects,
locate Q1 away from sensitive analog circuitry , including
XTR117. Mount Q1 so that heat is conducted to the
outside of the transducer housing.

The XTR117 is designed to use virtually any NPN
transistor with sufficient voltage, current and power
rating. Case style and thermal mounting considerations
often influence the choice for any given application.
Several possible choices are listed in Figure 1. A
MOSFET transistor will not improve the accuracy of the
XTR117 and is not recommended.

For improved precision use an external
voltage reference.

DEVICE VOLTAGE

REF3140
REF3130
REF3125

Use REF32xx for lower drift.

(V

)

REF

4.096V

3.0V

2.5V

Input

Circuitry

5V

V

IN

from I
All return current

R

20k

REG

I

REG

IN

I

IN

Ω

and I

REF

XTR117

V

REG

8

I

IN

I

2

RET

3

R

1

2.475k

A1

Ω

Figure 1. Basic Circuit Connections

+5V

Regulator

Possible choices for Q1(see text):

TYPE PACKAGE

MJE3440

TIP41C

MJD3340

V+
7

B

6

E

LIM

5

I

O

4

R

R

2

Ω

25

Q1

SOT−32
TO−220

D−PAK

C

OUT

10nF

I=100(I

I

O

V

LOOP

R

L

)

IN

5