PRECISION VOLTAGE-TO-CURRENT CONVERTER/TRANSMITTER

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XTR0 SBOSA JANUARY 98 REVISED AUGUST 003 PRECISION VOLTAGE-TO-CURRENT CONVERTER/TRANSMITTER FEATURES ma TO 0mA TRANSMITTER SELECTABLE INPUT/OUTPUT RANGES: 0V to +V, 0V to +0V Inputs 0mA to 0mA, ma to

1 XTR0 SBOSA JANUARY 98 REVISED AUGUST 003 PRECISION VOLTAGE-TO-CURRENT CONVERTER/TRANSMITTER FEATURES ma TO 0mA TRANSMITTER SELECTABLE INPUT/OUTPUT RANGES: 0V to +V, 0V to +0V Inputs 0mA to 0mA, ma to ma Outputs Other Ranges 0.00% MAX NONLINEARITY, BIT PRECISION +0V REFERENCE OUTPUT SINGLE SUPPLY OPERATION WIDE SUPPLY RANGE: 3.V to 0V DESCRIPTION The XTR0 is a precision voltage-to-current converter designed for analog signal transmission. It accepts inputs of 0 to V or 0 to 0V and can be connected for outputs of to 0mA, 0 to 0mA, to ma and many other commonly used ranges. A precision on-chip metal film resistor network provides input scaling and current offsetting. An internal 0V voltage reference can be used to drive external circuitry. The XTR0 is available in -pin plastic DIP, ceramic DIP and SOL- surface-mount packages. Commercial and industrial temperature range models are available. APPLICATIONS INDUSTRIAL PROCESS CONTROL PRESSURE/TEMPERATURE TRANSMITTERS CURRENT-MODE BRIDGE EXCITATION GROUNDED TRANSDUCER CIRCUITS CURRENT SOURCE REFERENCE FOR DATA ACQUISITION PROGRAMMABLE CURRENT SOURCE FOR TEST EQUIPMENT POWER PLANT/ENERGY SYSTEM MONITORING V REF Force V REF Sense V REF Adjust V IN (0V) V REF In V IN (V) Common 3 R R R +0V Reference R 3 R A R 8 A R 7 R 6 R V CC Source Resistor Source Sense Gate Drive Offset (zero) Adjust Span Adjust ma Span ma Span 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. 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. Copyright , Texas Instruments Incorporated

2 SPECIFICATIONS ELECTRICAL At T A = + C and V CC = +V and R L = 0Ω**, unless otherwise specified. XTR0AG, KP, KU XTR0BG PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS TRANSMITTER Transfer Function I O = 0 [(V REF In/) + (V IN /) + (V IN /)] /R SPAN Input Range: V () IN Specified Performance 0 +0 * * V V IN Specified Performance 0 + * * V Current, I O Specified Performance () 0 * * ma Derated Performance () 0 0 * * ma Nonlinearity ma/0ma Span () % of Span Offset Current, I OS I O = ma () Initial () % of Span vs Temperature () * % of Span/ C vs Supply, V CC () * * % of Span/V Span Error I O = 0mA Initial () % of Span vs Temperature () % of Span/ C vs Supply, V CC () * * % of Span/V Output Resistance From Drain of FET (Q EXT ) (3) 0 x 0 9 * Ω Input Resistance V IN 7 * kω V IN * kω V REF In 9 * kω Dynamic Response Settling Time To 0.% of Span * µs To 0.0% of Span 0 * µs Slew Rate.3 * ma/µs VOLTAGE REFERENCE Output Voltage * +0.0 V vs Temperature ppm/ C vs Supply, V CC Line Regulation * * %/V vs Output Current Load Regulation * * %/ma vs Time 00 * ppm/k hrs Trim Range * * V Output Current Specified Performance 0 * ma POWER SUPPLY Input Voltage, V CC * * V Quiescent Current Excluding I O 3. * * ma TEMPERATURE RANGE Specification: AG, BG 0 +8 * * C KP, KU C Operating: AG, BG + * * C KP, KU +8 C * Specifications same as AG/KP grades. ** Specifications apply to the range of R L shown in Typical Performance Curves. NOTES: () Including internal reference. () Span is the change in output current resulting from a full-scale change in input voltage. (3) Within compliance range limited by (+V CC V) +V DS required for linear operation of the FET. () For V REF adjustment circuit see Figure 3. () For extended I REF drive circuit see Figure. () Unit may be damaged. See section, Input Voltage Range. ABSOLUTE MAXIMUM RATINGS Power Supply, +V CC... 0V Input Voltage, V IN, V IN, V REF IN... +V CC See text regarding safe negative input voltage range. Storage Temperature Range: A, B... C to + C K, U... 0 C to +8 C Lead Temperature (soldering, 0s) G, P C (wave soldering, 3s) U C Output Short-Circuit Duration, Gate Drive and V REF Force... Continuous to common and +V CC Output Current Using Internal 0Ω Resistor... 0mA 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. XTR0 SBOSA

3 PIN CONFIGURATION PACKAGE INFORMATION Top View PACKAGE DRAWING PRODUCT PACKAGE NUMBER () Source Resistor Common V REF In V IN (0V) 3 3 +V CC V REF Force Gate Drive Source Sense XTR0AG -Pin Ceramic DIP 09 XTR0BG -Pin Ceramic DIP 09 XTR0KP -Pin Plastic DIP 80 XTR0KU SOL- Surface-Mount NOTE: () For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. V IN (V) V REF Sense Zero Adjust 6 V REF Adjust Zero Adjust 7 0 ma Span Span Adjust 8 9 ma Span ORDERING INFORMATION TEMPERATURE PRODUCT PACKAGE RANGE XTR0AG -Pin Ceramic DIP 0 C to +8 C XTR0BG -Pin Ceramic DIP 0 C to +8 C XTR0KP -Pin Plastic DIP 0 C to +70 C XTR0KU SOL- Surface-Mount 0 C to +70 C TYPICAL PERFORMANCE CURVES T A = + C, V CC = VDC, R L = 0Ω, unless otherwise noted. 0 V REF LINE REGULATION vs FREQUENCY 0 I O POWER SUPPLY REGULATION vs FREQUENCY V REF / V CC (%/V) I O / V CC (% of span/v) k 0k 00k k 0k 00k Ripple Frequency (Hz) Ripple Frequency (Hz) Junction Temperature Rise Above Ambient ( C) Max. T J = +7 C JA = 70 C/W JUNCTION TEMPERATURE RISE vs V REF OUTPUT CURRENT Max. Temp. Rise for +8 C Ambient V CC = +0V V CC = +V V CC = +V Error (% of span) 0 TOTAL OUTPUT ERROR vs TEMPERATURE AG BG AG V REF Output Current (ma) (I OUT has minimal effect on T J ) Temperature ( C) XTR0 3 SBOSA

TYPICAL PERFORMANCE CURVES (CONT) At T A = + C, V CC = VDC, R L = 0Ω, unless

Temperature ( C) 0 0 30 3 0 +V CC (V) SETTLING TIME WITH NEG V IN STEP PULSE

4 TYPICAL PERFORMANCE CURVES (CONT) At T A = + C, V CC = VDC, R L = 0Ω, unless otherwise noted. I CC vs TEMPERATURE 00 MAXIMUM R L vs V CC I CC (ma) (excluding I O ) 3 I O = 0mA I O = ma R L (Ω) I O MAX = 0mA I O MAX = 0mA Temperature ( C) V CC (V) SETTLING TIME WITH NEG V IN STEP PULSE RESPONSE V IN V IN 0V 0V 0V I O Error (0.0% of Span/Box) I O into 00Ω 0V SETTLING TIME WITH POS V IN STEP V IN 0V 0V I O Error (0.0% of Span/Box) XTR0 SBOSA

5 APPLICATIONS INFORMATION Figure shows the basic connections required for 0 to 0V input and to 0mA output. Other input voltage and output current ranges require changes in connections of pins 3,,, 9 and 0 as shown in the table of Figure. The complete transfer function of the XTR0 is: (V REF IN ) (V IN ) (V IN) I O = () R SPAN R SPAN is the internal 0Ω resistor, R 9, when connected as shown in Figure. An external R SPAN can be connected for different output current ranges as described later. EXTERNAL TRANSISTOR An external pass transistor, Q EXT, is required as shown in Figure. This transistor conducts the output signal current. A P-channel MOSFET transistor is recommended. It must have a voltage rating equal or greater than the maximum power supply voltage. Various recommended types are shown in Table I. MANUFACTURER PART NO. BV () DSS BV () GS PACKAGE Ferranti ZVP30A 0V 0V TO-9 ZVP30B 0V 0V TO-39 ZVP306A 60V 0V TO-9 ZVP306B 60V 0V TO-39 International Rectifier IRF93 60V 0V TO-0 Motorola MTP8P08 80V 0V TO-0 RCA RFLP08 80V 0V TO-39 RFTP08 80V 0V TO-0 Siliconix VP0300B 30V 0V TO-39 (preferred) VP0300L 30V 0V TO-9 VP0300M 30V 0V TO-37 VP0808B 80V 0V TO-39 VP0808L 80V 0V TO-9 VP0808M 80V 0V TO-37 Supertex VP30N 0V 0V TO-0 VP30N3 0V 0V TO-9 VP306N 60V 0V TO-0 VP306N3 60V 0V TO-9 NOTE: () BV DSS Drain-source breakdown voltage. BV GS Gate-source breakdown voltage. TABLE I. Available P-Channel MOSFETs. Force +V CC + µf +V CC 3. to 0V V IN 0 to 0V Sense V REF Adj. 3 R R kω R.kΩ kω +0V Reference R 3 0kΩ R 0kΩ I O /0 I O /0 R 8 00Ω R 9 0Ω R 7 60Ω Short Connection (see text) Zero Adjust Span Adjust ma Span I O Q EXT P-Channel MOSFET (see text) I O to 0mA R L (0Ω typ) 9 ma Span R 6 6.Ω INPUT OUTPUT RANGE (V) RANGE (ma) PIN 3 PIN PIN PIN 9 PIN Com Input Com Com Com -0-0 Com Input Com Com Com V Ref Input Com Com Open V Ref Input Com Com Com Com Com Input Com Com - -0 Com Com Input Com Com V Ref Com Input Com Open V Ref Com Input Com Com FIGURE. Basic Circuit Connection. XTR0 SBOSA

6 If the supply voltage, +V CC, exceeds the gate-to-source breakdown voltage of Q EXT, and the output connection (drain of Q EXT ) is broken, Q EXT could fail. If the gate-tosource breakdown voltage is lower than +V CC, Q EXT can be protected with a V zener diode connected from gate to source. Two PNP discrete transistors (Darlington-connected) can be used for Q EXT see Figure. Note that an additional capacitor is required for stability. Integrated Darlington transistors are not recommended because their internal base-emitter resistors cause excessive error. XTR0 3 7nF 0.07µF N907 etc. TIP30B etc. I OUT +V CC R L TRANSISTOR DISSIPATION Maximum power dissipation of Q EXT depends on the power supply voltage and full-scale output current. Assuming that the load resistance is low, the power dissipated by Q EXT is: P MAX = (+V CC ) I FS () The transistor type and heat sinking must be chosen according to the maximum power dissipation to prevent overheating. See Table II for general recommendations. PACKAGE TYPE TO-9 TO-37 TO-39 TO-0 TO-3 ALLOWABLE POWER DISSIPATION Lowest: Use minimum supply and at + C. Acceptable: Trade-off supply and temperature. Good: Adequate for majority of designs. Excellent: For prolonged maximum stress. Use if hermetic package is required. TABLE II. External Transistor Package Type and Dissipation. INPUT VOLTAGE RANGE The internal op amp A can be damaged if its non-inverting input (an internal node) is pulled more than 0.V below common (0V). This could occur if input pins 3, or were driven with an op amp whose output could swing negative under abnormal conditions. The voltage at the input of A is: (V REF IN ) (V IN ) (V IN ) V A = + + (3) This voltage should not be allowed to go more negative than 0.V. If necessary, a clamp diode can be connected from the negative-going input to common to clamp the input voltage. COMMON (Ground) Careful attention should be directed toward proper connection of the common (grounds). All commons should be joined at one point as close to pin of the XTR0 as possible. The exception is the I OUT return. It can be returned to any point where it will not modulate the common at pin. VOLTAGE REFERENCE The reference voltage is accurately regulated at pin (V REF SENSE ). To preserve accuracy, any load including pin Common FIGURE. Q EXT Using PNP Transistors. V REF +0V REF Q REF V REF Force V REF Sense V REF Adjust R 0kΩ Force Sense R S () Adjust Range ±% Optimum FIGURE 3. Optional Adjustment of Reference Voltage. For 00mA with V CC up to 0V use N30 for Q REF. +V CC XTR0 XTR0 FIGURE. Increasing Reference Current Drive. 3 should be connected to this point. The circuit in Figure 3 shows adjustment of the voltage reference. The current drive capability of the XTR0 s internal reference is 0mA. This can be extended if desired by adding an external NPN transistor shown in Figure. OFFSET (ZERO) ADJUSTMENT The offset current can be adjusted by using the potentiometer, R, shown in Figure. Set the input voltage to zero and then adjust R to give ma at the output. For spans starting +V CC NOTE: () R S gives higher resolution with reduced range, set R S = 0Ω for larger range. Common 6 XTR0 SBOSA

7 0V to +0V 3 6 R Offset Adjust 7 XTR0 8 9 R R R 3 Span Adjust 3 µf Tantalum G S D Third Wire V + ma to 0mA Out R L 0Ω V to +V Out. Output Current, I O (ma) 0 0 ma Span Zero Adjust ±.8% Optimum ma Offset R = 00kΩ R = 00kΩ R 3 = 9.9kΩ R = 3.6Ω Span Adjust ±0.% as shown Input Voltage, V IN (V) FIGURE 6. Zero and Span of 0V to +0V Input, ma to 0mA Output Configuration (see Figure ). FIGURE. Offset and Span Adjustment Circuit for 0V to +0V Input, ma to 0mA Output. 0 at 0mA, the following special procedure is recommended: set the input to a small nonzero value and then adjust R to the proper output current. When the input is zero the output will be zero. Figures 6 and 7 show graphically how offset is adjusted. Output Current, I O (ma) 0 See values in Figure 6. In addition, connect pins 9 and 0 together. 0mA Span Span Adjust SPAN ADJUSTMENT The span is adjusted at the full-scale output current using the potentiometer, R, shown in Figure. This adjustment is interactive with the offset adjustment, and a few iterations may be necessary. For the circuit shown, set the input voltage to +0V full scale and adjust R to give 0mA fullscale output. Figures 6 and 7 show graphically how span is adjusted. The values of R, R 3, and R for adjusting the span are determined as follows: choose R in series to slightly decrease the span; then choose R and R 3 to increase the span to be adjustable about the center value. LOW TEMPERATURE COEFFICIENT OPERATION Although the precision resistors in the XTR0 track within ppm/ C, the output current depends upon the absolute temperature coefficient (TC) of any one of the resistors, R 6, R 7, R 8, and R 9. Since the absolute TC of the output current can have 0ppm/ C, maximum, the TC of the output current can have 0ppm/ C drift. For low TC operation, zero TC resistors can be substituted for either the span resistors (R 6 or R 7 ) or for the source resistor (R 9 ) but not both. Zero Adjust 0mA Offset Input Voltage, V IN (V) FIGURE 7. Zero and Span of 0V to +0V IN, 0mA to 0mA Output Configuration (see Figure ). EXTENDED SPAN For spans beyond 0mA, the internal 0Ω resistor (R 9 ) may be replaced by an external resistor connected between pins 3 and. Its value can be calculated as follows: R EXT = R 9 (Span OLD /Span NEW ) Since the internal thin-film resistors have a 0% absolute value tolerance, measure R 9 before determining the final value of R EXT. Self-heating of R EXT can cause nonlinearity. Therefore, choose one with a low TC and adequate power rating. See Figure 0 for application. XTR0 7 SBOSA

8 TYPICAL APPLICATIONS The XTR0 is ideal for a variety of applications requiring high noise immunity current-mode signal transmission. The precision +0V reference can be used to excite bridges and transducers. Selectable ranges make it very useful as a precision programmable current source. The compact design and low price of the XTR0 allow versatility with a minimum of external components and design engineering expense. Figures 8 through 0 show typical applications of the XTR0. +V V IN +0V Reference 3 R Ω A T 3 7 R 9 kω 6 Offset Adjust R 0 kω A R 7.7kΩ R MΩ R 3 0kΩ 9 R 6 0Ω R 8 00Ω Fine Trim RH 0kΩ Course Trim Span Adjust T 3 A I O A T R kω R.99Ω V I O (ma) R, R : Low TC resistors to dissipate 0.3W continuous power. For other current ranges, scale both resistors proportionately. R 8, R 0, R : 0-turn trimpots for greatest sensitivity. R 6, R 7 : Low TC resistors. V IN (V) A - A : / LM3 (powered by ±V). T 0 : International Rectifier IR93 (). T : International Rectifier IR3 (). T 3 : International Rectifier IRFF93 (). NOTE: () Or other adequate power rating MOS transistor. FIGURE 8. ±00mA Current Pump. 8 XTR0 SBOSA

9 Isolation Barrier +V Isolated Power Supply (7) µf V +V V +V ISO 0 to 0V XTR0 9 3 G S D ma to 0mA Out R L V L FIGURE 9. Isolated ma to 0mA Channel. +V 3 R EXT 0.Ω 0V to +0V 3 XTR0 G S 0A to 0A Out 9 D See extended span section. FIGURE 0. 0A to 0A Output Voltage-to-Current Converter. XTR0 9 SBOSA

10 PACKAGE DRAWINGS 0 XTR0 SBOSA

11 PACKAGE DRAWINGS (CONT) XTR0 SBOSA

12 PACKAGE OPTION ADDENDUM 8-Mar-00 PACKAGING INFORMATION Orderable Device Status () Package Type Package Drawing Pins Package Qty Eco Plan () Lead/Ball Finish MSL Peak Temp (3) XTR0AG NRND CDIP SB JD None Call TI Level-NA-NA-NA XTR0BG NRND CDIP SB JD None Call TI Level-NA-NA-NA XTR0KP ACTIVE PDIP N Pb-Free (RoHS) Call TI Level-NC-NC-NC XTR0KU ACTIVE SOIC DW 8 None CU NIPDAU Level--0C- YEAR XTR0KU/K ACTIVE SOIC DW 000 None CU SNPB Level--0C- YEAR () 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. () Eco Plan - May not be currently available - please check for the latest availability information and additional product content details. None: Not yet available Lead (Pb-Free). 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.% 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" and in addition, uses package materials that do not contain halogens, including bromine (Br) or antimony (Sb) above 0.% of total product weight. (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDECindustry 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. Addendum-Page

16 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using TI components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products Applications Amplifiers amplifier.ti.com Audio /audio Data Converters dataconverter.ti.com Automotive /automotive DSP dsp.ti.com Broadband /broadband Interface interface.ti.com Digital Control /digitalcontrol Logic logic.ti.com Military /military Power Mgmt power.ti.com Optical Networking /opticalnetwork Microcontrollers microcontroller.ti.com Security /security Telephony /telephony Video & Imaging /video Wireless /wireless Mailing Address: Texas Instruments Post Office Box 6303 Dallas, Texas 76 Copyright 00, Texas Instruments Incorporated

PRECISION VOLTAGE-TO-CURRENT CONVERTER/TRANSMITTER

XTR0 SBOSB JANUARY 98 REVISED APRIL 007 PRECISION VOLTAGE-TO-CURRENT CONVERTER/TRANSMITTER FEATURES ma TO 0mA TRANSMITTER SELECTABLE INPUT/OUTPUT RANGES: 0V to +V, 0V to +0V Inputs 0mA to 0mA, ma to ma