FEATURES
D
LOW QUIESCENT CURRENT: 130
A
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 PACKAGE
APPLICATIONS
D
2-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 XTR117 is a precision current output converter designed
to transmit analog 4-20mA signals over an industry- standard
current loop. It provides accurate current scaling and output
current limit functions.
The on-chip voltage regulator (5V) can be used to power
external circuitry. A current return pin (I
RET
) senses any
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 at www.ti.com.
A1
V
IN
R
IN
R
1
2.475k
R
2
25
R
LIM
Q1
V
REG
I
IN
I
RET
E
B
V+
R
L
V
LOOP
I
O
7
6
5
4
8
2
3
I
O
= 100 V
IN
R
IN
XTR117
+5V
Regulator
XTR117
SBOS344 - SEPTEMBER 2005
4-20mA Current-Loop Transmitter
PRODUCTION DATA information is current as of publication date. Products
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.
www.ti.com
Copyright
2005, Texas Instruments Incorporated
All trademarks are the property of their respective owners.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
XTR117
SBOS344 - SEPTEMBER 2005
www.ti.com
2
ABSOLUTE MAXIMUM RATINGS
(1)
Power Supply, V+ (referenced to IO pin)
+50V
. . . . . . . . . . . . . . . .
Input Voltage, (referenced to IRET pin)
0V to V+
. . . . . . . . . . . . . . .
Output Current Limit
Continuous
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
VREG, Short-Circuit
Continuous
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
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.
Exposure to absolute maximum conditions for extended periods
may degrade device reliability. These are stress ratings only, and
functional operation of the device at these or any other conditions
beyond those specified is not implied.
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.
ESD damage can range from subtle performance degradation to
complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could
cause the device not to meet its published specifications.
PACKAGE/ORDERING INFORMATION
(1)
PRODUCT
PACKAGE-LEAD
PACKAGE
DESIGNATOR
PACKAGE
MARKING
ORDERING NUMBER
TRANSPORT MEDIA,
QUANTITY
XTR117
MSOP-8
DGK
BOZ
XTR117AIDGKT
Tape and Reel, 250
XTR117
MSOP-8
DGK
BOZ
XTR117AIDGKR
Tape and Reel, 2500
XTR117(2)
DFN-8
DRB
BOY
XTR117AIDRBT
Tape and Reel, 250
XTR117(2)
DFN-8
DRB
BOY
XTR117AIDRBR
Tape and Reel, 3000
(1) For the most current package and ordering information, see the Package Option Addendum located at the end of this data sheet.
(2) Available Q1 2006.
PIN ASSIGNMENTS
Top View
1
2
3
4
8
7
6
5
1
2
3
4
8
7
6
5
Exposed
Thermal
Die Pad
on
Underside
(2)
DFN-8
(3)
MSOP-8
NC
(1)
I
IN
I
RET
I
O
NC
(1)
I
IN
I
RET
I
O
V
REG
V+
B (Base)
E (Emitter)
V
REG
V+
B (Base)
E (Emitter)
NOTES: (1) NC = No connection. Leave unconnected on PCB.
(2) Connect thermal die pad to V
-
.
(3) Available Q1 2006.
XTR117
XTR117
XTR117
SBOS344 - SEPTEMBER 2005
www.ti.com
3
ELECTRICAL CHARACTERISTICS: V+ = +24V
Boldface limits apply over the temperature range, T
A
= -40
C to +125
C.
All specifications at T
A
= +25
C, V+ = 24V, R
IN
= 20k
, and TIP29C external transistor, unless otherwise noted.
XTR117
PARAMETER
CONDITION
MIN
TYP
MAX
UNITS
OUTPUT
Output Current Equation
I
O
I
O
= IIN x 100
Output Current, Linear Range
0.20
25
mA
Over-Scale Limit
I
LIM
32
mA
Under-Scale Limit
I
MIN
I
REG
= 0
0.13
0.20
mA
SPAN
Span (Current Gain)
S
100
A/A
Error
(1)
I
O
= 200
A to 25mA
0.05
0.4
%
vs Temperature
T
A
= -40
C to +125
C
+
3
+
20
ppm/
C
Nonlinearity
I
O
= 200
A to 25mA
0.003
0.02
%
INPUT
Offset Voltage (Op Amp)
V
OS
I
IN
= 40
A
100
500
V
vs Temperature
T
A
= -40
C to +125
C
+
0.7
+
6
m
V/
C
vs Supply Voltage, V+
V+ = 7.5V to 40V
+0.1
+2
V/V
Bias Current
I
B
-35
nA
vs Temperature
T
A
= -40
C to +125
C
150
pA/
C
Noise: 0.1Hz to 10Hz
e
n
0.6
V
PP
DYNAMIC RESPONSE
Small-Signal Bandwidth
C
LOOP
= 0, R
L
= 0
380
kHz
Slew Rate
3.2
mA/
s
V
REG
(2)
Voltage
5
V
Voltage Accuracy
I
REG
= 0
0.05
0.1
V
vs Temperature
T
A
= -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 SUPPLY
Specified Voltage Range
V+
+24
V
Operating Voltage Range
+7.5
+40
V
Quiescent Current
I
Q
130
200
A
Over Temperature
T
A
= -40
C to +125
C
250
m
A
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
IN
.
(2) Voltage measured with respect to I
RET
pin.
XTR117
SBOS344 - SEPTEMBER 2005
www.ti.com
4
TYPICAL CHARACTERISTICS: V+ = +2.7V to +5.5V
At TA = +25
C, V+ = 24V, RIN = 20k
, and TIP29C external transistor, unless otherwise noted.
10k
100k
Frequency (Hz)
CURRENT GAIN vs FREQUENCY
1M
45
40
30
20
10
Ga
i
n
(d
B
)
C
OUT
= 10nF
R
L
= 250
C
OUT
= 0
R
L
= 0
-
75
-
50
-
25
0
25
50
75
100
Temperature (
_
C)
QUIESCENT CURRENT vs TEMPERATURE
125
180
170
160
150
140
130
120
110
100
90
80
Q
u
i
e
s
c
ent
C
u
r
r
ent
(
A)
V+ = 36V
V+ = 7.5V
V+ = 24V
-
75
-
50
-
25
0
25
50
75
100
Temperature (
_
C)
OVER-SCALE CURRENT vs TEMPERATURE
125
34
33
32
31
30
29
28
O
v
er
-
S
c
a
l
e
C
u
r
r
ent
(
m
A
)
V+ = 7.5V
V+ = 36V
V+ = 24V
With External Transistor
-
1
0
1
2
3
I
REG
Current (mA)
V
REG
VOLTAGE vs V
REG
CURRENT
4
5.5
5.0
4.5
V
RE
G
V
o
l
t
age
(
V
)
+25
_
C
+25
_
C
-
55
_
C
+125
_
C
Sinking
Current
Sourcing
Current
-
55
_
C
+125
_
C
-
75
-
50
-
25
0
25
50
75
100
Temperature (
_
C)
SPAN ERROR vs TEMPERATURE
125
50
40
30
20
10
0
-
10
-
20
-
30
-
40
-
50
Sp
a
n
E
r
r
o
r
(
m
%
)
Offset Voltage (
V)
OFFSET VOLTAGE DISTRIBUTION
P
opul
ati
o
n
-
50
0
-
45
0
-
40
0
-
35
0
-
30
0
-
25
0
-
20
0
-
15
0
-
10
0
-
50
0
50
100
150
200
250
300
350
400
450
500
XTR117
SBOS344 - SEPTEMBER 2005
www.ti.com
5
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 Q
1
.
External input circuitry connected to the XTR117 can be
powered from V
REG
. Current drawn from these
terminals must be returned to I
RET
, pin 3. The I
RET
pin is
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 I
O
= 100 x I
IN
. The
input voltage at the I
IN
pin is zero (referred to the I
RET
pin). A voltage input is converted to an input current with
an external input resistor, R
IN
, 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 effects of offset voltage and
drift of A1.
EXTERNAL TRANSISTOR
The external transistor, Q
1
, 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 Q
1
will still
cause ambient temperature changes that can influence
the XTR117 performance. To minimize these effects,
locate Q
1
away from sensitive analog circuitry, including
XTR117. Mount Q
1
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.
A1
(V
REF
)
XTR117
+5V
Regulator
Input
Circuitry
Q1
I
O
R
LIM
R
2
25
R
1
2.475k
R
IN
20k
I
RET
I
IN
I
IN
V
IN
V
REG
I
REG
from I
REG
and I
REF
All return current
I
O
V
LOOP
R
L
E
B
V+
C
OUT
10nF
I = 100 (I
IN
)
5V
6
5
4
8
2
3
7
MJE3440
TIP41C
MJD3340
SOT-32
TO-220
D-PAK
TYPE
PACKAGE
Possible choices for Q1 (see text):
REF3140
REF3130
REF3125
4.096V
3.0V
2.5V
DEVICE
VOLTAGE
Use REF32xx for lower drift.
For improved precision use an external
voltage reference.
Figure 1. Basic Circuit Connections
XTR117
SBOS344 - SEPTEMBER 2005
www.ti.com
6
MINIMUM OUTPUT CURRENT
The quiescent current of the XTR117 (typically 130
A)
is the lower limit of its output current. Zero input current
(I
IN
= 0) will produce an I
O
equal to the quiescent current.
Output current will not begin to increase until
I
IN
> I
Q
/100. Current drawn from V
REG
will be added to
this minimum output current. Up to 3.8mA is available
to power external circuitry while still allowing the output
current to go below 4mA.
OFFSETTING THE INPUT
A low-scale output of 4mA is produced by creating a
40
A input current. This input current can be created
with the proper value resistor from an external
reference voltage (V
REF
) as shown in Figure 2. V
REG
can be used as shown in Figure 2 but will not have the
temperature stability of a high quality reference such as
the REF3125.
A1
R
1
2.475k
R
IN
62.5k
V
REG
V
REF
(2.5V) or
...................
40
A
0 to 160
A
I
IN
I
RET
8
2
3
XTR117
Figure 2. Creating Low-Scale Offset
MAXIMUM OUTPUT CURRENT
The XTR117 provides accurate, linear output up to
25mA. Internal circuitry limits the output current to
approximately 32mA to protect the transmitter and loop
power/measurement circuitry.
It is possible to extend the output current range of the
XTR117 by connecting an external resistor from pin 3
to pin 5, to change the current limit value. Since all
output current must flow through internal resistors, it is
possible to cause internal damage with excessive
current. Output currents greater than 45mA may cause
permanent damage.
REVERSE-VOLTAGE PROTECTION
The XTR117 low compliance voltage rating (minimum
operating voltage) of 7.5V permits the use of various
voltage protection methods without compromising
operating range. Figure 3 shows a diode bridge circuit
which allows normal operation even when the voltage
connection lines are reversed. The bridge causes a two
diode drop (approximately 1.4V) loss in loop supply
voltage. This voltage drop results in a compliance
voltage of approximately 9V--satisfactory for most
applications. A diode can be inserted in series with the
loop supply voltage and the V+ pin to protect against
reverse output connection lines with only a 0.7V loss in
loop supply voltage.
A1
+5V
Regulator
Q1
E
B
V+
R
L
V
L OO P
7
6
5
0.01
F
4
8
2
3
IN4148
V
REG
R
IN
R
1
2.475k
R
2
25
D
1
(1 )
R
LIM
R
IN
I
O
= 100 V
IN
V
IN
I
IN
I
R E T
XTR117
NOTE: (1) Some examples of zener diodes include: P6KE51 or 1N4755A. Use lower
voltage zener diodes with loop power-supply voltages < 30V for increased protection. See
Over- voltage Surge Protection.
Maximum V
PS
must be less
than minimum voltage rating
of the zener diode.
The diode bridge causes a
1.4V loss in loop supply voltage.
See Reverse- Voltage Protection.
Figure 3. Reverse Voltage Operation and Over-Voltage Surge Protection
XTR117
SBOS344 - SEPTEMBER 2005
www.ti.com
7
OVER-VOLTAGE SURGE PROTECTION
Remote connections to current transmitters can
sometimes be subjected to voltage surges. It is prudent
to limit the maximum surge voltage applied to the
XTR117 to as low as practical. Various zener diode and
surge clamping diodes are specially designed for this
purpose. Select a clamp diode with as low a voltage
rating as possible for best protection. Absolute
maximum power-supply rating on the XTR117 is
specified at +50V. Keep overvoltages and transients
below +50V to ensure reliable operation when the
supply returns to normal (7.5V to 40V).
Most surge protection zener diodes have a diode
characteristic in the forward direction that will conduct
excessive current, possibly damaging receiving-side
circuitry if the loop connections are reversed. If a surge
protection diode is used, a series diode or diode bridge
should be used for protection against reversed
connections.
RADIO FREQUENCY INTERFERENCE
The long wire lengths of current loops invite radio
frequency (RF) interference. RF interference can be
rectified by the input circuitry of the XTR117 or
preceding circuitry. This effect generally appears as an
unstable output current that varies with the position of
loop supply or input wiring. Interference may also enter
at the input terminals. For integrated transmitter
assemblies with short connections to the sensor, the
interference more likely comes from the current loop
connections.
8
2
3
Digital
Control
Optical
Isolation
8
2
R
IN
R
FILTER
C
FILTER
C
R
IN
V
REG
I
IN
I
RET
V
REG
I
IN
I
O
D/A
V
O
D/A
I
RET
V
REG
I
IN
I
RET
3
8
2
3
Digital
Control
Optical
Isolation
PWM
Out
XTR117
XTR117
XTR117
Figure 4. Digital Control Methods
XTR117
SBOS344 - SEPTEMBER 2005
www.ti.com
8
A1
+5V
Regulator
Q1
E
B
V+
7
6
5
4
8
2
3
P
+125
_
C
-
40
_
C
Ext Temp
Ext Temp
Nonlinear
Bridge
Transducer
Fault
Monitor
Int Temp
Temp
ADC
Digital
Temperature
Compensation
Auto-Zero
PGA
Over/Under
Scale Limiter
Control Register
Interface Circuitry
EEPROM
(SOT23-5)
Digital Calibration
NOTE: (1) PGA309 V
O UT
: 0.5V to 4.5V.
50
0
ps i
T
R
L
V
L O O P
I
O
V
R E G
V
S
R
IN
25k
R
O S
125k
Linear
2.5V
Ref
Lin DAC
Linearization
Circuit
Analog Sensor Linearization
Analog Signal Conditioning
V
O U T
(1)
R
1
2.475k
R
2
25
R
L IM
R
IN
I
O
= 100 V
I N
I
I N
I
R E T
XTR117
PGA309
Figure 5. Complete 4-20mA Pressure Transducer Solution with PGA309 and XTR117
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package
Type
Package
Drawing
Pins Package
Qty
Eco Plan
(2)
Lead/Ball Finish
MSL Peak Temp
(3)
XTR117AIDGKR
ACTIVE
MSOP
DGK
8
2500
TBD
Call TI
Call TI
XTR117AIDGKT
ACTIVE
MSOP
DGK
8
250
TBD
Call TI
Call TI
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco
Plan
-
The
planned
eco-friendly
classification:
Pb-Free
(RoHS)
or
Green
(RoHS
&
no
Sb/Br)
-
please
check
http://www.ti.com/productcontent
for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
PACKAGE OPTION ADDENDUM
www.ti.com
17-Oct-2005
Addendum-Page 1
IMPORTANT NOTICE
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dsp.ti.com
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www.ti.com/broadband
Interface
interface.ti.com
Digital Control
www.ti.com/digitalcontrol
Logic
logic.ti.com
Military
www.ti.com/military
Power Mgmt
power.ti.com
Optical Networking
www.ti.com/opticalnetwork
Microcontrollers
microcontroller.ti.com
Security
www.ti.com/security
Telephony
www.ti.com/telephony
Video & Imaging
www.ti.com/video
Wireless
www.ti.com/wireless
Mailing Address:
Texas Instruments
Post Office Box 655303 Dallas, Texas 75265
Copyright
2005, Texas Instruments Incorporated
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