Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsXTR106U

XTR106

4-20mA CURRENT TRANSMITTER

with Bridge Excitation and Linearization

FEATURES

● LOW TOTAL UNADJUSTED ERROR

● 2.5V, 5V BRIDGE EXCITATION REFERENCE

● 5.1V REGULATOR OUTPUT

● LOW SPAN DRIFT: ±25ppm/°C max

● LOW OFFSET DRIFT: 0.25µV/°C

● HIGH PSR: 110dB min

● HIGH CMR: 86dB min

● WIDE SUPPLY RANGE: 7.5V to 36V

● 14-PIN DIP AND SO-14 SURFACE-MOUNT

APPLICATIONS

● PRESSURE BRIDGE TRANSMITTERS

● STRAIN GAGE TRANSMITTERS

● TEMPERATURE BRIDGE TRANSMITTERS

● INDUSTRIAL PROCESS CONTROL

● SCADA REMOTE DATA ACQUISITION

● REMOTE TRANSDUCERS

● WEIGHING SYSTEMS

● ACCELEROMETERS

DESCRIPTION

The XTR106 is a low cost, monolithic 4-20mA, two-

wire current transmitter designed for bridge sensors. It

provides complete bridge excitation (2.5V or 5V refer-

ence), instrumentation amplifier, sensor linearization,

and current output circuitry. Current for powering ad-

ditional external input circuitry is available from the

REG

pin.

The instrumentation amplifier can be used over a wide

range of gain, accommodating a variety of input signal

types and sensors. Total unadjusted error of the com-

plete current transmitter, including the linearized bridge,

is low enough to permit use without adjustment in many

applications. The XTR106 operates on loop power sup-

ply voltages down to 7.5V.

Linearization circuitry provides second-order correction

to the transfer function by controlling bridge excitation

voltage. It provides up to a 20:1 improvement in

nonlinearity, even with low cost transducers.

The XTR106 is available in 14-pin plastic DIP and

SO-14 surface-mount packages and is specified for the

–40°C to +85°C temperature range. Operation is from

–55°C to +125°C.

XTR106

–

OUT

RET

4-20mA

7.5V to 36V

REF

2.5V

REF

LIN

Lin

Polarity

REG

(5.1V)

BRIDGE NONLINEARITY CORRECTION

USING XTR106

Bridge Output (mV)

2.0

1.5

1.0

0.5

–0.5

Uncorrected

Bridge Output

Corrected

Nonlinearity (%)

SBOS092A – JUNE 1998 – REVISED NOVEMBER 2003

www.ti.com

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.

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.

All trademarks are the property of their respective owners.

Summary of content (22 pages)

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XTR106 XTR 106 X TR 1 06 SBOS092A – JUNE 1998 – REVISED NOVEMBER 2003 4-20mA CURRENT TRANSMITTER with Bridge Excitation and Linearization FEATURES APPLICATIONS ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● LOW TOTAL UNADJUSTED ERROR 2.5V, 5V BRIDGE EXCITATION REFERENCE 5.1V REGULATOR OUTPUT LOW SPAN DRIFT: ±25ppm/°C max LOW OFFSET DRIFT: 0.25µV/°C HIGH PSR: 110dB min HIGH CMR: 86dB min WIDE SUPPLY RANGE: 7.
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SPECIFICATIONS At TA = +25°C, V+ = 24V, and TIP29C external transistor, unless otherwise noted. XTR106P, U PARAMETER CONDITIONS OUTPUT Output Current Equation Output Current, Specified Range Over-Scale Limit Under-Scale Limit IO IOVER IUNDER ZERO OUTPUT(1) Initial Error vs Temperature vs Supply Voltage, V+ vs Common-Mode Voltage (CMRR) vs VREG (IO) Noise: 0.1Hz to 10Hz IZERO IO = VIN 4 24 1 2.9 • (40/RG) + 4mA, VIN in Volts, RG in Ω 20 ✻ 28 30 ✻ ✻ 1.6 2.2 ✻ ✻ 3.4 4 ✻ ✻ VIN = 0V, RG = ∞ 4 ±5 ±0.
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ABSOLUTE MAXIMUM RATINGS(1) PIN CONFIGURATION Top View DIP and SOIC VREG 1 14 VREF5 V– IN 2 13 VREF2.5 RG 3 12 Lin Polarity RG 4 11 RLIN + VIN 5 10 V+ IRET 6 9 B (Base) IO 7 8 E (Emitter) Power Supply, V+ (referenced to IO pin) .......................................... 40V + – Input Voltage, VIN, VIN (referenced to IRET pin) ......................... 0V to V+ Storage Temperature Range ....................................... –55°C to +125°C Lead Temperature (soldering, 10s) ......
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FUNCTIONAL DIAGRAM VREG Lin Polarity 12 RLIN V+ 11 1 10 VREF5 VREF2.5 14 REF Amp Bandgap VREF 5.1V 13 Lin Amp Current Direction Switch + VIN 5 4 100µA B 9 RG 975Ω 25Ω 3 – VIN 2 I = 100µA + E VIN RG 8 7 6 IO = 4mA + VIN • ( 40 ) RG IRET 4 XTR106 www.ti.
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TYPICAL PERFORMANCE CURVES At TA = +25°C, V+ = 24V, unless otherwise noted. TRANSCONDUCTANCE vs FREQUENCY RG = 50Ω 50 STEP RESPONSE CCOUT 0.01µF OUT==0.01µF COUT = 0.033µF COUT = 0.
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TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, V+ = 24V, unless otherwise noted. UNDER-SCALE CURRENT vs TEMPERATURE UNDER-SCALE CURRENT vs IREF + IREG 4.0 2.5 Under-Scale Current (mA) Under-Scale Current (mA) 3.5 2.0 1.5 1.0 0.5 2.5 2.0 TA = +25°C 1.5 0.5 0 0 –75 –50 –25 0 25 50 75 100 0 125 0.5 1.0 1.5 2.0 Temperature (°C) IREF + IREG (mA) OVER-SCALE CURRENT vs TEMPERATURE ZERO OUTPUT ERROR vs VREF and VREG CURRENTS 2.5 3.0 30 With External Transistor 2.
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TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, V+ = 24V, unless otherwise noted.
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TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, V+ = 24V, unless otherwise noted. REFERENCE VOLTAGE DEVIATION vs TEMPERATURE REFERENCE VOLTAGE DRIFT PRODUCTION DISTRIBUTION 40 30 25 20 15 10 5 Reference Voltage Deviation (%) Percent of Units (%) 35 0.1 Typical production distribution of packaged units. 0 0 –0.1 VREF = 5V –0.2 VREF = 2.5V –0.3 –0.4 –0.
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APPLICATIONS INFORMATION The transfer function for the complete current transmitter is: IO = 4mA + VIN • (40/RG) Figure 1 shows the basic connection diagram for the XTR106. The loop power supply, VPS, provides power for all circuitry. Output loop current is measured as a voltage across the series load resistor, RL. A 0.01µF to 0.03µF supply bypass capacitor connected between V+ and IO is recommended. For applications where fault and/or overload conditions might saturate the inputs, a 0.
PAGE 10
EXTERNAL TRANSISTOR External pass transistor, Q1, conducts the majority of the signal-dependent 4-20mA loop current. Using an external transistor isolates the majority of the power dissipation from the precision input and reference circuitry of the XTR106, maintaining excellent accuracy. Since the external transistor is inside a feedback loop its characteristics are not critical. Requirements are: VCEO = 45V min, β = 40 min and PD = 800mW.
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Figure 4, but not peaking exactly at mid-scale can be substantially improved. A sensor with a “S-shaped” nonlinearity curve (equal positive and negative nonlinearity) cannot be improved with the XTR106’s correction circuitry. The value of RLIN is chosen according to Equation 4 shown in Figure 3. RLIN is dependent on a linearization factor, KLIN, which differs for the 2.5V reference and 5V reference.
PAGE 12
UNDER-SCALE CURRENT When using linearity correction, care should be taken to insure that the sensor’s output common-mode voltage remains within the XTR106’s allowable input range of 1.1V to 3.5V. Equation 6 in Figure 3 can be used to calculate the XTR106’s new excitation voltage. The common-mode voltage of the bridge output is simply half this value if no common-mode resistor is used (refer to the example in Figure 3). Exceeding the common-mode range may yield unpredicatable results.
PAGE 13
to the upper and lower sides of the bridge to keep the bridge output within the 1.1V to 3.5V common-mode input range. Bridge output is reduced so a preamplifier as shown may be needed to reduce offset voltage and drift. OTHER SENSOR TYPES The XTR106 can be used with a wide variety of inputs. Its high input impedance instrumentation amplifier is versatile and can be configured for differential input voltages from millivolts to a maximum of 2.4V full scale. The linear range of the inputs is from 1.1V to 3.
PAGE 14
REVERSE-VOLTAGE PROTECTION The XTR106’s low compliance rating (7.5V) permits the use of various voltage protection methods without compromising operating range. Figure 6 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 results in a compliance voltage of approximately 9V—satisfactory for most applications.
PAGE 15
VREF5 0.01µF See ISO124 data sheet if isolation is needed. 1MΩ VREF2.5 4.8kΩ 6kΩ Isothermal Block 14 20kΩ OPA277 5 + 13 11 RLIN VIN 7.5V to 36V 1 VREG 4 Type K 1N4148 IO 4-20 mA XTR106 3 V+ RG RG 1kΩ 1MΩ(1) 10 E RG Lin Polarity – 2 VIN IRET 9 COUT 0.01µF Q1 VO 8 + VPS – RL IO 7 12 IO = 4mA + VIN • ( 40 ) RG 6 5.2kΩ 50Ω B VREG (pin 1) 100Ω 2kΩ NOTE: (1) For burn-out indication. 0.01µF FIGURE 7.
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PACKAGE OPTION ADDENDUM www.ti.
PAGE 17
PACKAGE OPTION ADDENDUM www.ti.com 24-Jan-2013 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.
PAGE 18
PACKAGE MATERIALS INFORMATION www.ti.com 9-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant XTR106U/2K5 SOIC D 14 2500 330.0 16.4 6.5 9.0 2.1 8.0 16.0 Q1 XTR106UA/2K5 SOIC D 14 2500 330.0 16.4 6.5 9.0 2.1 8.0 16.
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PACKAGE MATERIALS INFORMATION www.ti.com 9-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) XTR106U/2K5 SOIC D 14 2500 367.0 367.0 38.0 XTR106UA/2K5 SOIC D 14 2500 367.0 367.0 38.
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