1
XTR115, XTR116
2000 Burr-Brown Corporation
PDS-1582A
Printed in U.S.A. January, 2000
XTR115
XTR116
4-20mA CURRENT LOOP TRANSMITTERS
FEATURES
q
LOW QUIESCENT CURRENT: 200
A
q
5V REGULATOR FOR EXTERNAL CIRCUITS
q
V
REF
FOR SENSOR EXCITATION:
XTR115: 2.5V
XTR116: 4.096V
q
LOW SPAN ERROR: 0.05%
q
LOW NONLINEARITY ERROR: 0.003%
q
WIDE LOOP SUPPLY RANGE: 7.5V to 36V
q
SO-8 PACKAGE
APPLICATIONS
q
2-WIRE, 4-20mA CURRENT LOOP
TRANSMITTER
q
SMART TRANSMITTER
q
INDUSTRIAL PROCESS CONTROL
q
TEST SYSTEMS
q
COMPATIBLE WITH HART MODEM
q
CURRENT AMPLIFIER
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VOLTAGE-TO-CURRENT AMPLIFIER
DESCRIPTION
The XTR115 and XTR116 are precision current out-
put converters designed to transmit analog 4-to-20mA
signals over an industry standard current loop. They
provide accurate current scaling and output current
limit functions.
The on-chip voltage regulator (5V) can be used to
power external circuitry. A precision on-chip V
REF
(2.5V for XTR115 and 4.096V for XTR116) can be
used for offsetting or to excite transducers. A current
return pin (I
RET
) senses any current used in external
circuitry to assure an accurate control of the output
current.
The XTR115 is a fundamental building block of
smart sensors using 4-to-20mA current transmission.
The XTR115 and XTR116 are specified for opera-
tion over the extended industrial temperature range,
40
C to +85
C.
XTR115
XTR116
International Airport Industrial Park Mailing Address: PO Box 11400, Tucson, AZ 85734 Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 Tel: (520) 746-1111
Twx: 910-952-1111 Internet: http://www.burr-brown.com/ Cable: BBRCORP Telex: 066-6491 FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132
For most current data sheet and other product
information, visit www.burr-brown.com
R
IN
I
IN
V
IN
+
I
RET
XTR115
XTR116
+5V
Regulator
R
2
25
R
LIM
E
B
V+
R
1
2.475k
I
O
=
100 V
IN
R
IN
A1
Voltage
Reference
+5V
V
REG
V
REF
2
3
8
1
5
4
7
6
XTR115: 2.5V
XTR116: 4.096V
R
L
V
LOOP
I = 100
I
IN
2
XTR115, XTR116
T
Specifications the same as XTR115U and XTR116U.
NOTES: (1) Does not include initial error or TCR of R
IN
. (2) Voltage measured with respect to I
RET
pin.
SPECIFICATIONS
At T
A
= +25
C, V+
= 24V, R
IN
= 20k
, and TIP29C external transistor, unless otherwise noted.
XTR115U
XTR115UA
XTR116U
XTR116UA
PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
OUTPUT
Output Current Equation
I
O
I
O
= I
IN
100
T
Output Current, Linear Range
0.25
25
T
T
mA
Over-Scale Limit
I
LIM
32
T
mA
Under-Scale Limit
I
MIN
I
REG
= 0, I
REF
= 0
0.2
0.25
T
T
mA
SPAN
Span (Current Gain)
S
100
T
A/A
Error
(1)
I
IN
= 250
A to 25mA
0.05
0.2
T
0.4
%
vs Temperature
T
A
= 40
C to +85
C
3
20
T
T
ppm/
C
Nonlinearity
I
IN
= 250
A to 25mA
0.003
0.01
T
0.02
%
INPUT
Offset Voltage (Op Amp)
V
OS
I
IN
= 40
A
100
250
T
500
V
vs Temperature
T
A
= 40
C to +85
C
0.7
3
T
6
V/
C
vs Supply Voltage, V+
V+ = 7.5V to 36V
0.1
2
T
T
V/V
Bias Current
I
B
35
T
nA
vs Temperature
150
T
pA/
C
Noise: 0.1Hz to 10Hz
e
n
0.6
T
Vp-p
DYNAMIC RESPONSE
Small Signal Bandwidth
C
LOOP
= 0, R
L
= 0
380
T
kHz
Slew Rate
3.2
T
mA/
s
V
REF
(2)
XTR115
2.5
T
V
XTR116
4.096
T
V
Voltage Accuracy
I
REF
= 0
0.05
0.25
T
0.5
%
vs Temperature
T
A
= 40
C to +85
C
20
35
T
75
ppm/
C
vs Supply Voltage, V+
V+ = 7.5V to 36V
1
10
T
T
ppm/V
vs Load
I
REF
= 0mA to 2.5mA
100
T
ppm/mA
Noise: 0.1Hz to 10Hz
10
T
Vp-p
Short-Circuit Current
16
T
mA
V
REG
(2)
Voltage
5
T
V
Voltage Accuracy
I
REG
= 0
0.05
0.1
T
T
V
vs Temperature
T
A
= 40
C to +85
C
0.1
T
mV/
C
vs Supply Voltage, V+
V+ = 7.5V to 36V
1
T
mV/V
vs Output Current
See Typical Curves
Short-Circuit Current
12
T
mA
POWER SUPPLY
V+
Specified
+24
T
V
Voltage Range
+7.5
+36
T
T
V
Quiescent Current
200
250
T
T
A
Over Temperature, 40
C to +85
C
240
300
T
T
A
TEMPERATURE RANGE
Specification
40
+85
T
T
C
Operating
55
+125
T
T
C
Storage
55
+125
T
T
C
Thermal Resistance
JA
150
T
C/W
3
XTR115, XTR116
Power Supply, V+ (referenced to I
O
pin) .......................................... 40V
Input Voltage (referenced to I
RET
pin) ........................................ 0V to V+
Output Current Limit ............................................................... Continuous
V
REG
, Short-Circuit .................................................................. Continuous
V
REF
, Short-Circuit .................................................................. Continuous
Operating Temperature ................................................ 55
C to +125
C
Storage Temperature Range ....................................... 55
C to +125
C
Lead Temperature (soldering, 10s) .............................................. +300
C
Junction Temperature ................................................................... +165
C
NOTE: (1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods may degrade
device reliability.
ABSOLUTE MAXIMUM RATINGS
(1)
Top View
SO-8
PIN CONFIGURATION
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Burr-Brown
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
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the user's own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.
PACKAGE
SPECIFIED
DRAWING
TEMPERATURE
PACKAGE
ORDERING
TRANSPORT
PRODUCT
PACKAGE
NUMBER
RANGE
MARKING
NUMBER
(1)
MEDIA
XTR115UA
SO-8
182
40
C to +85
C
XTR115UA
XTR115UA
Rails
"
"
"
"
"
XTR115UA/2K5
Tape and Reel
XTR115U
SO-8
182
40
C to +85
C
XTR115U
XTR115U
Rails
"
"
"
"
"
XTR115U/2K5
Tape and Reel
XTR116UA
SO-8
182
40
C to +85
C
XTR116UA
XTR116UA
Rails
"
"
"
"
"
XTR116UA/2K5
Tape and Reel
XTR116U
SO-8
182
40
C to +85
C
XTR116U
XTR116U
Rails
"
"
"
"
"
XTR116U/2K5
Tape and Reel
NOTES: (1) Models with a slash (/ ) are available only in Tape and Reel in the quantities indicated (e.g., /2K5 indicates 2500 devices per reel). Ordering 2500 pieces
of "XTR115UA/2K5" will get a single 2500-piece Tape and Reel.
V
REF
I
IN
I
RET
I
O
V
REG
V+
B (Base)
E (Emitter)
1
2
3
4
8
7
6
5
4
XTR115, XTR116
TYPICAL PERFORMANCE CURVES
At T
A
= +25
C, V+
= 24V, R
IN
= 20k
, and TIP29C external transistor, unless otherwise noted.
10k
100k
Frequency (Hz)
CURRENT GAIN vs FREQUENCY
1M
40
30
20
10
Gain (dB)
C
OUT
= 10nF
R
L
= 250
C
OUT
= 0
R
L
= 0
75
50
25
0
25
50
75
100
Temperature (
C)
REFERENCE VOLTAGE vs TEMPERATURE
125
0.1
0
0.1
0.2
0.3
Reference Voltage (%)
75
50
25
0
25
50
75
100
Temperature (
C)
QUIESCENT CURRENT vs TEMPERATURE
125
260
240
220
200
180
160
Quiescent Current (
A)
(V+) = 36V
(V+) = 24V
(V+) = 7.5V
75
50
25
0
25
50
75
100
Temperature (
C)
OVER-SCALE CURRENT vs TEMPERATURE
125
34
33
32
31
30
29
28
Over-Scale Current (mA)
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
REG
Voltage (V)
+25
C
+25
C
55
C
+125
C
Sinking
Current
Sourcing
Current
55
C
+125
C
5
XTR115, XTR116
APPLICATIONS INFORMATION
The XTR115 and XTR116 are identical devices except for
the reference voltage output, pin 1. This voltage is available
for external circuitry and is not used internally. Further
discussions that apply to both devices will refer to the
"XTR115/6."
Figure 1 shows basic circuit connections with representative
simplified input circuitry. The XTR115/6 is a two-wire
current transmitter. Its input signal (pin 2) controls the output
current. A portion of this current flows into the V+ power
supply, pin 7. The remaining current flows in Q1. External
input circuitry connected to the XTR115/6 can be powered
from V
REG
or V
REF
. Current drawn from these terminals
must be returned to I
RET
, pin 3. This I
RET
pin is a "local
ground" for input circuitry driving the XTR115/6.
The XTR115/6 is a current-input device with a gain of 100.
A current flowing into pin 2 produces I
O
= 100 I
IN
. The
input voltage at the I
IN
pin is zero (referred to the I
RET
pin).
A voltage input is created with an external input resistor, as
shown. Common full-scale input voltages range from 1V
and upward. Full-scale inputs greater than 0.5V are recom-
mend to minimize the effect of offset voltage and drift of A1.
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 XTR115/6 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 affect the XTR115/6. To minimize these effects,
locate Q1 away from sensitive analog circuitry, including
XTR115/6. Mount Q1 so that heat is conducted to the
outside of the transducer housing.
The XTR115/6 is designed to use virtually any NPN transis-
tor 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 XTR115/6 and is not recommended.
R
IN
20k
I
IN
2
V
IN
I
RET
3
XTR115
XTR116
+5V
Regulator
R
2
25
R
LIM
E
5
I
O
4
B
6
V+
7
R
1
2.475k
R
L
V
LOOP
A1
Voltage
Reference
V
REG
5V
V
REF
8
1
XTR115: 2.5V
XTR116: 4.096V
Possible choices for Q
1
(see text).
2N4922
TIP29C
TIP31B
TYPE
TO-225
TO-220
TO-220
PACKAGE
I = 100
I
IN
I
O
10nF
I
REF
I
IN
All return current
from I
REG
and I
REF
For I
O
= 4mA to 20mA
I
IN
= 40
A to 200
A
With R
IN
= 20k
V
IN
= 0.8V to 4V
I
REG
Q
1
Input
Circuitry
FIGURE 1. Basic Circuit Connections.
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