LH0094 Multifunction Converter General Description The LH0094 multifunction converter generates an output voltage per the transfer function: EO e Vy VZ m #V J , 0.1sms10, m continuously adjustable X m is set by 2 resistors. Y Y Y Y Y Y Low cost Versatile High accuracyb0.05% Wide supply rangeb g 5V to g 22V Y Y Y Y Y Block and Connection Diagrams Minimum component count Internal matched resistor pair for setting m e 2 and m e 0.5 Applications Y Features Y Y Precision divider, multiplier Square root Square Trigonometric function generator Companding Linearization Control systems Log amp Dual-In-Line Package Order Number LH0094CD See NS Package Number D16D Simplified Schematic TL/H/5695 – 1 C1995 National Semiconductor Corporation TL/H/5695 RRD-B30M115/Printed in U. S. A. LH0094 Multifunction Converter February 1995 Absolute Maximum Ratings (Note 1) Operating Temperature Range LH0094CD If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage g 22V Input Voltage Output Short-Circuit Duration g 22V Storage Temperature Range LH0094CD b 25§ C to a 85§ C b 55§ C to a 125§ C Lead Temperature (Soldering, 10 seconds) Continuous 260§ C Electrical Characteristics VZm VS e g 15V, TA e 25§ C unless otherwise specified. Transfer function: EO e VY ; 0.1 s m s 10; OV s VX, VY, VZ s 10V VX Parameter LH0094C Conditions Min Units Typ Max 0.45 0.1 0.2 0.9 0.45 0.1 0.2 0.9 % F.S. % F.S. mV/§ C 0.45 0.15 0.9 % F.S. % F.S. 2.0 % F.S. % F.S. ACCURACY Multiply Untrimmed External Trim Divide Untrimmed External Trim Square Root Untrimmed External Trim Square Untrimmed External Trim Low Level Square Root Exponential Circuits EO e VZVY (0.03sVYs10V; 0.01sVZs10V) (Figure 2) (Figure 3) vs. Temperature EO e 10VZ/VX (Figure 4), 0.5sVXs10; 0.01sVZs10) (Figure 5), (0.1sVXs10; 0.01sVZs10) vs. Temperature EO e 100VZ/10 (Figure 8), (0.03sVZs10 (Figure 9), (0.01sVZs10 EO e 10 (VZ/10)2 (0.1sVZs10) (Figure 6) (Figure 7) EO e 010VZ; 5.0mVsVZs10V, (Figure 10) 1.0 0.15 % F.S. (10V) % F.S. mV/§ C 0.05 % F.S. m e 0.2, EO e 10 (VZ/10)2 (Figure 11), (0.1sVZs10) m e 5.0, EO e 10 (VZ/10)5 (Figure 11), (1.0sVZs10) 0.08 0.08 % F.S. % F.S. VX e 10V, VY e VZ e 0 5.0 m e 1.0, VX e 10V, VY e 0.1 Vrms 10 Hz to 1.0 kHz, m e 1.0, VY e VZ e OV VX e 10V VX e 0.1V 10 kHz 100 300 mV/rms mV/rms OUTPUT OFFSET 10 mV AC CHARACTERISTICS 3 dB Bandwidth Noise EXPONENT m 0.2 to 5.0 0.1 to 10 0 98 100 V kX 12 1.0 3.0 V X mA INPUT CHARACTERISTICS Input Voltage Input Impedance (For Rated Performance) (All Inputs) 10 OUTPUT CHARACTERISTICS Output Swing Output Impedance Supply Current (RLs10k) 10 (VS e g 15V) (Note 1) Note 1: Refer to RETS0094D drawing for specifications of the military LH00940 version. 2 5.0 Applications Information (b) mk1 GENERAL INFORMATION Power supply bypass capacitors (0.1 mF) are recommended for all applications. The LH0094 series is designed for positive input signals only. However, negative input up to the supply voltage will not damage the device. A clamp diode (Figure 1 ) is recommended for those applications in which the inputs may be subjected to open circuit or negative input signals. For basic applications (multiply, divide, square, square root) it is possible to use the device without any external adjustments or components. Two matched resistors are provided internally to set m for square or square root. When using external resistors to set m, such resistors should be as close to the device as possible. me R2 R1 a R2 & 200X R1 a R2 (c) ml1 me R1 a R2 R2 TL/H/5695 – 4 ACCURACY (ERROR) The accuracy of the LH0094 is specified for both externally adjusted and unadjusted cases. Although it is customary to specify the errors in percent of full-scale (10V), it is seen from the typical performance curves that the actual errors are in percent of reading. Thus, the specified errors are overly conservative for small input voltages. An example of this is the LH0094 used in the multiplication mode. The specified typical error is 0.25% of fullscale (25 mV). As seen from the curve, the unadjusted error is & 25 mV at 10V input, but the error is less than 10 mV for inputs up to 1V. Note also that if either the multiplicand or the multiplier is at less than 10V, (5V for example) the unadjusted error is less. Thus, the errors specified are at fullscaleÐthe worst case. The LH0094 is designed such that the user is able to externally adjust the gain and offset of the deviceÐthus trim out all of the errors of conversion. In most applications, the gain adjustment is the only external trim needed for super accuracyÐexcept in division mode, where a denominator offset adjust is needed for small denominator voltages. SELECTION OF RESISTORS TO SET m Internal Matched Resistors RA and RB are matched internal resistors. They are 100X g 10%, but matched to 0.1%. (a) m e 2* (b) m e 0.5* EXPONENTS The LH0094 is capable of performing roots to 0.1 and powers up to 10. However, care should be taken when applying these exponentÐotherwise, results may be misinterpreted. For example, consider the (/10th power of a number: i.e., 0.001 raised to 0.1 power is 0.5011; 0.1 raised to the 0.1 power is 0.7943; and 10 raised to the 0.1 power is 1.2589. Thus, it is seen that while the input has changed 4 decades, the output has only changed a little more than a factor of 2. It is also seen that with as little as 1 mV of offset, the output will also be greater than zero with zero input. TL/H/5695 – 2 *No external resistors required, strap as indicated External Resistors The exponent is set by 2 external resistors or it may be continuously varied by a single trim pot. (R1 a R2s500X. (a) m e 1 TL/H/5695 – 3 3 Applications Information (Continued) 1. CLAMP DIODE CONNECTION EO e Vy #V J VZ m X 0.1 s m s 10 Note. This clamp diode connection is recommended for those applications in which the inputs may be subject to open circuit or negative signals. FIGURE 1. Clamp Diode Connection 2. MULTIPLY FIGURE 2a. LH0094 Used to Multiply (No External Adjustment) FIGURE 2b. Typical Performance of LH0094 in Multiply Mode Without External Adjustment E0 e Vy Vz 10 me1 Trim Procedure Set VZ e VY e 10V Adjust R2 until output e 10.000V TL/H/5695 – 5 FIGURE 3. Precision Multiplier (0.02% Typ) with 1 External Adjustment 4 Applications Information (Continued) 3. DIVIDE FIGURE 4a. LH0094 Used to Divide (No External Adjustment) FIGURE 4b. Typical Performance, Divide Mode, Without External Adjustments Trim Procedures Apply 10V to VY, 0.1V to VX and VZ. Adjust R3 until EO e 10.000V. Apply 10.000V to all inputs. Adjust R2 until EO e 10.000V Repeat procedure. FIGURE 5. Precision Divider (0.05% Typ) 4. SQUARE EO e Vy #V J VZ 2 X TL/H/5695 – 6 FIGURE 6b. Squaring Mode without External Adjustment FIGURE 6a. Basic Connection of LH0094 (m e 2) without External Adjustment Using Internal Resistors to Set m 5 Applications Information (Continued) 4. SQUARE (Continued) Vz 2 # 10 J EO e 10 Trim Procedure Apply 10V to VZ Adjust R2 for 10.000V at output FIGURE 7. Precision Squaring Circuit (0. 15% Typ) 5. SQUARE ROOT EO e Vy Vz (/2 #V J x FIGURE 8a. Basic Connection of LH0094 (m e 0.5) without External Adjustment Using Internal Resistors to Set m FIGURE 8b. Typical Performance Curve Square Root, No External Adjustment EO e 10 010 VZ Trim Procedure Apply 10V to all inputs. Adjust R2 until EO e 10.000V TL/H/5695 – 7 FIGURE 9. Precision Square Rooter (0.15% Typ) 6 Applications Information (Continued) 6. LOW LEVEL SQUARE ROOT me1 EO e 10 VZ EO EO2 e 10 VZ . . . EO e 010 VZ 5 mV s VZ s 10V Trim Procedure Set VZ e 10V Adjust R2 until output e 10.000V FIGURE 10. 3-Decade Precision Square Root Circuit Using the LH0094 with m e 1 Typical Applications EO e 10 # 10 J VZ m Trim Procedure Apply 10V to all inputs Adjust R2 for output of 10.000V For m e 0.2 For m e 5 TL/H/5695 – 8 me R2 ; Choose R1 e 200X R1 a R2 . . . R2 e 50X me R1 a R2 ; Choose R2 e 50X R2 . . . R1 e 200X FIGURE 11. Precision Exponentiator (m e 0.2 to 5) 7 Typical Applications (Continued) Note. The LH0094 may be used to generate a voltage equivalent to: V0 e 0V12 a V22 V0 e V2 a V12 V0 a V2 V02 a V0 V2 e V2 V0 a V22 a V12 V02 e V12 a V22 . . . V0 e 0V12 a V22 V1, V2 0 x 10V R & 10k National Semiconductor resistor array RA08Ð10k is recommended FIGURE 12. Vector Magnitude Function TL/H/5695 – 9 Note. The LH0094 may be used in direct measurement of gas flow. Flow e k EO e 10 PDP VP VDP c VT EO EO2 e 10 EO e 0T VP VDP VT 010 VP VDP VT P e Absolute pressure T e Absolute temperature DP e Pressure drop FIGURE 13. Mass Gas Flow Circuit 8 Typical Applications (Continued) TL/H/5695 – 10 Note. The LH0094 may also be used to generate the Log of a ratio of 2 voltages. The output is taken from pin 14 of the LH0094 for the Log application. KT VZ fin q VX ELOG e K1 where K1 e If K1 e R1 a R2 R2 1 KT/qfin10 then ELOG e Log10 VZ VX R1 e 15.9 R2 R2 & 400X R2 must be a thermistor with a tempco of & 0.33%/§ C to be compensated over temperature. FIGURE 14. Log Amp Application 9 LH0094 Multifunction Converter Physical Dimensions inches (millimeters) Order Number LH0094CD NS Package Number D16D LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Corporation 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Europe Fax: (a49) 0-180-530 85 86 Email: cnjwge @ tevm2.nsc.com Deutsch Tel: (a49) 0-180-530 85 85 English Tel: (a49) 0-180-532 78 32 Fran3ais Tel: (a49) 0-180-532 93 58 Italiano Tel: (a49) 0-180-534 16 80 National Semiconductor Hong Kong Ltd. 13th Floor, Straight Block, Ocean Centre, 5 Canton Rd. Tsimshatsui, Kowloon Hong Kong Tel: (852) 2737-1600 Fax: (852) 2736-9960 National Semiconductor Japan Ltd. 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