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
XTR115
XTR116
+5V
V
REG
8
V
REF
1
Voltage
Reference
+5V
Regulator
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.
V+
7
XTR115: 2.5V
XTR116: 4.096V
V
LOOP
R
IN
+
V
IN
–
3
I
RET
R
1
2.475kΩ
R
LIM
R
2
25Ω
I
O
=
4
I = 100 • I
IN
100 V
IN
R
IN
I
IN
2
A1
E
5
B
6
R
L
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
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.
V
REF
I
IN
I
RET
I
O
1
2
3
4
8
7
6
5
V
REG
V+
B (Base)
E (Emitter)
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
PACKAGE
DRAWING
NUMBER
182
SPECIFIED
TEMPERATURE
RANGE
–40°C to +85°C
PACKAGE
MARKING
XTR115UA
ORDERING
NUMBER
(1)
XTR115UA
XTR115UA/2K5
XTR115U
XTR115U/2K5
XTR116UA
XTR116UA/2K5
XTR116U
XTR116U/2K5
TRANSPORT
MEDIA
Rails
Tape and Reel
Rails
Tape and Reel
Rails
Tape and Reel
Rails
Tape and Reel
PRODUCT
XTR115UA
PACKAGE
SO-8
"
XTR115U
"
SO-8
"
182
"
–40°C to +85°C
"
XTR115U
"
XTR116UA
"
SO-8
"
182
"
–40°C to +85°C
"
XTR116UA
"
XTR116U
"
SO-8
"
182
"
–40°C to +85°C
"
XTR116U
"
"
"
"
"
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.
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.
®
3
XTR115, XTR116
TYPICAL PERFORMANCE CURVES
At T
A
= +25°C, V+ = 24V, R
IN
= 20kΩ, and TIP29C external transistor, unless otherwise noted.
CURRENT GAIN vs FREQUENCY
260
40
QUIESCENT CURRENT vs TEMPERATURE
Quiescent Current (µA)
240
(V+) = 36V
220
(V+) = 24V
Gain (dB)
30
C
OUT
= 0
R
L
= 0Ω
C
OUT
= 10nF
R
L
= 250Ω
200
(V+) = 7.5V
20
180
10
10k
100k
Frequency (Hz)
1M
160
–75
–50
–25
0
25
50
75
100
125
Temperature (°C)
REFERENCE VOLTAGE vs TEMPERATURE
0.1
OVER-SCALE CURRENT vs TEMPERATURE
34
With External Transistor
33
32
V+ = 36V
31
V+ = 7.5V
30
V+ = 24V
29
∆
Reference Voltage (%)
0
–0.1
–0.2
–0.3
–75
–50
–25
0
25
50
75
100
125
Temperature (°C)
Over-Scale Current (mA)
28
–75
–50
–25
0
25
50
75
100
125
Temperature (°C)
V
REG
VOLTAGE vs V
REG
CURRENT
5.5
+125°C
–55°C
V
REG
Voltage (V)
+25°C
5.0
+25°C
–55°C
Sinking
Current
4.5
–1
0
Sourcing
Current
+125°C
1
2
3
4
I
REG
Current (mA)
®
XTR115, XTR116
4
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.
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