SC7106/7107 31/2 DIGITS, LCD/LED DISPLAY , A/D CONVERTERS FOR DMM DESCRIPTION The SC7106 and SC7107 are high performance, low power, 3 1/2 digit A/D converters. Included are seven segment decoders, display drivers, a reference, and a clock. The SC7106 is designed to interface with a liquid DIP-40-600-2.54 crystal display (LCD) and includes a multiplexed backplane drive; the SC7107 will directly drive an instrument size light emitting diode (LED) display. The SC7106 and SC7107 bring together a combination of high accuracy, versatility, and true economy. It features auto-zero to less than 10µV, zero drift of less than 1µV/°C, input bias current of 10pA (Max), QFP-44-10 x10-0.8 and rollover error of less than one count. True differential inputs and reference are useful in all systems, but give the designer an uncommon advantage when measuring load cells, strain gauges and other bridge type transducers. Finally, the true economy of single power supply operation (SC7106), enables a high performance panel meter to be built with the addition of only 10 passive components and a display. FEATURES * Guaranteed zero reading for 0V input on all scales * True polarity at zero for precise null detection ORDERING INFORMATION Part No. * Low power dissipation-typically Temp. Range(°C) Package SC7106CPL 0~70 DIP-40-600-2.54 SC7106RCPL 0~70 DIP-40-600-2.54 SC7106 0~70 QFP-44-10X10-0.8 SC7107CPL 0~70 DIP-40-600-2.54 SC7107RCPL 0~70 DIP-40-600-2.54 SC7107 0~70 QFP-44-10X10-0.8 NOTE: “R”indicates device with reversed leads for mounting to PC board less than 10mW * True differential input and reference, direct display driveLCD SC7106, LED SC7107 * Low noise (less than 15µVp-p) * On chip clock and reference * 1pA typical input current * No additional active circuits required underside. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 1 of 22 SC7106/7107 BLOCK DIAGRAM ABSOLUTE MAXIMUM RATING Characteristics Symbol Value V+ ~ V- 15 Supply Voltage SC7107 V+ ~ GND 6 SC7107 V- ~ GND -9 SC7106 Analog Input Voltage(Either Input) (Note 1) V+ ~ V- Reference Input Voltage(Either Input) V+ ~ V- Clock Input SC7106 TEST to V+ SC7107 GND to V+ Unit V Operating Temperature Topr 0 ~ +70 °C Storage Temperature Tstg -65 ~ 150 °C θJA 50 °C/W 150 °C Thermal resistance(typical) (Note 2) Maximum Junction Temperature NOTE: 1. Input voltages may exceed the supply voltages provided the input current is limited to ±100µA. 2. θJA is measured with the component mounted on an evaluation PC board in free air. 3. Not tested, guaranteed by design. 4. Back plane drive is in phase with segment drive for "off" segment, 180 degrees out of phase for "on" segment. Frequency is 20 times conversion rate. Average DC component is less than 50mV. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 2 of 22 SC7106/7107 ELECTRICAL CHARACTERISTICS(Unless otherwise noted, specificatons apply to both the SC7106 and SC7107 at Tamb=25°C, Fclock=48kHz, SC7106 is tested in the circuit of Figure 1. SC7107 is tested in the circuit of Figure 2.) Characteristics Test Conditions Min. Typ. Max. Unit SYSTEM PERFORMANCE Zero Input Reading Ratiometric Reading VIN=0.0V, Full Scale=200mV VIN=VREF, VREF=100mV -000.0 999 ±000. +000. Digital 0 999/ 1000 0 1000 Reading Digital Reading -VIN=+VIN ≈ 200mV Rollover Error Difference In Reading For Equal Positive -- ±0.2 ±1 Counts -- ±0.2 ±1 Counts -- 50 -- µV/V -- 15 -- µV And Negative Inputs Near Full Scale Full Scale =200mV Or Full Scale =2V Linearity Maximum Deviation From Best Straight Line Fit (Note 3) Common Mode Rejection Ratio Noise VCM=1V,VIN=0V,Full Scale=200mV (Note 3) VIN=0V,Full Scale=200mV,(Peak-To-Peak Value Not Exceeded 95% of Time) Leakage Current Input VIN=0(Note 3) -- 1 10 pA Zero Reading Drift VIN=0, 0°C To 70°C(Note 3) -- 0.2 1 µV/°C -- 1 5 ppm/°C -- 1.0 1.8 mA -- 0.6 1.8 mA 2.4 3.0 3.2 V -- 80 -- ppm/°C 4 5.5 6 V 5 8 -- mA 10 16 -- mA 4 7 -- mA Scale Factor Temperature Coefficient VIN=199mV, 0°C TO 70°C (Ext.Ref.0ppm/°C) (Note 3) End Power Supply Character V+ VIN=0(Does Not Include LED Current For Supply Current SC7107) End Power Supply Character VSupply Current SC7107 Only COMMON Pin Analog Common 25kΩ Between Common And Positive Voltage Supply (With Respect To V+ Supply) Temperature Coefficient Of Analog 25kΩ Between Common And Positive Common Supply (With Respect To V+ Supply) DISPLAY DRIVER (SC7106 ONLY) Peak-To-Peak Segment Drive Voltage Peak-To-Peak Backplane Drive V+ To V-=9V(Note 4) Voltage DISPLAY DRIVER (SC7107 ONLY) Segment Sinking Current (Except Pins 19 And 20) Pin 19 Only V+=5V, Segment Voltage=3V Pin 20 Only HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 3 of 22 SC7106/7107 Http: www.silan.com.cn B3 B1 F3 C1 E3 D1 AB4 V+ POL HANGZHOU SILAN MICROELECTRONICS CO.,LTD OSC1 BP/GND OSC2 G3 HOLD A3 OSC3 C3 TEST G2 INTEN DEEN LB PIN CONFIGURATION REV:1.2 2006.02.27 Page 4 of 22 SC7106/7107 DESIGN INFORMATION SUMMARY SHEET OSCILLATOR FREQUENCY fosc=0.45/RC; Cosc>50pF; Rosc>50kΩ; fosc(Typ)=48kHz OSCILLATOR PERIOD tosc=RC/0.45 INTEGRATION CLOCK FREQUENCY Fclock=fosc/4 INTEGRATION PERIOD tINT=1000x(4/fosc) 60/50Hz REJECTION CRITERION tINT/ t60Hz or tINT/ t50Hz=Integer OPTIMUM INTEGRATION CURRENT IINT=4µA FULL SCALE ANALOG INPUT VOLTAGE VINFS(Typ)=200mV or 2V INTEGRATE RESISTOR RINT=VINFS/IINT INTEGRATE CAPACITOR CINT=(tINT) (IINT)/VINT INTEGRATOR OUTPUT VOLTAGE SWING VINT=(tINT) (IINT)/CINT VINT MAXIMUM SWING (V-+0.5V)<VINT<(V+-0.5V), VINT(Typ)=2V DISPLAY COUNT COUNT=1000x (VIN/VREF) CONVERSION CYCLE tCYC=tCLOCKx4000; tCYC=toscx16000; when fosc=48kHz; tCYC=333ms COMMON MODE INPUT VOLTAGE (V-+1V)<VIN<(V+-0.5V) AUTO-ZERO CAPACITOR 0.01µF<CAZ<1µF REFERENCE CAPACITOR 0. 1µF<CREF<1µF VCOM VCOM ≈ V+−2.8V SC7106 POWER SUPPLY: SINGLE 9V SC7106 DISPLAY: LCD SC7107 POWER SUPPLY:DUAL±5.0V SC7107 DISPLAY: LED Biased between Vi and VRegulation lost when V+ to V-<≈6.8V ;if VCOM is externally pulled down to (V+ to V-)/2, the VCOM circuit will turn off. V+ to V-=9V, digital supply is generated internally, VGND≈V+−4.5V Type: Direct drive with digital logic supply amplitude. V+=+5V TO GND, V-=-5V TO GND, Digital Logic and LED driver supply V+ to GND Type: Non-Multiplexed Common Anode HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 5 of 22 SC7106/7107 TYPICAL APPLICATIONS AND TEST CIRCUITS FIGURE 1.SC7106 TEST CIRCUIT AND TYPICAL APPLICATION WITH LCD DISPLAY COMPONENTS SELECTED FOR 200mV FULL SCALE FIGURE 2.SC7107 TEST CIRCUIT AND TYPICAL APPLICATION WITH LED DISPLAY COMPONENTS SELECTED FOR 200mV FULL SCALE HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 6 of 22 SC7106/7107 TYPICAL INTEGRATOR AMPLIFIER OUTPUT WAVEFORM (INT PIN) TOTAL CONVERSION TIME=4000xtCLOCK=16,000xtOSC FUNCTIONAL DESCRIPTION 1. ANALOG SECTION Figure 3 shows the Analog Section for the SC7106 and SC7107. Each measurement cycle is divided into three phases. They are (1) auto-zero (A-Z), (2) signal integrate (INT) and (3) de-integrate (DE). FIGURE 3. ANALOG SECTION OF SC7106 AND SC7107 2. AUTO-ZERO PHASE During auto-zero three things happen. First, input high and low are disconnected from the pins and internally shorted to analog COMMON. Second, the reference capacitor is charged to the reference voltage. Third, a feedback loop is closed around the system to charge the auto-zero capacitor CAZ to compensate for offset voltages in the buffer amplifier, integrator, and comparator. Since the comparator is included in the loop, the A-Z accuracy is limited only by the noise of the system. In any case, the offset referred to the input is less than 10µV. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 7 of 22 SC7106/7107 3. SIGNAL INTEGRATE PHASE During signal integrate, the auto-zero loop is opened, the internal short is removed, and the internal input high and low are connected to the external pins. The converter then integrates the differential voltage between IN HI and IN LO for a fixed time. This differential voltage can be within a wide common mode range: up to 1V from either supply. If, on the other hand, the input signal has no return with respect to the converter power supply, IN LO can be tied to analog COMMON to establish the correct common mode voltage. At the end of this phase, the polarity of the integrated signal is determined. 4. DE-INTEGRATE PHASE The final phase is de-integrate, or reference integrate. Input low is internally connected to analog COMMON and input high is connected across the previously charged reference capacitor. Circuitry within the chip ensures that the capacitor will be connected with the correct polarity to cause the integrator output to return to zero. The time required for the output to return to zero is proportional to input signal. Specifically the digital reading displayed is: DISPLAY COUNT=1000 (VIN/VREF). 5. DIFFERENTIAL INPUT The input can accept differential voltages anywhere within the common mode range of the input amplifier, or specifically from 0.5V below the positive supply to 1V above the negative supply. In this range, the system has a CMRR of 86dB typical. However, care must be exercised to assure the integrator output does not saturate. A worst case condition would be a large positive common mode voltage with a near full-scale negative differential input voltage. The negative input signal drives the integrator positive when most of its swing has been used up by the positive common mode voltage. For these critical applications the integrator output swing can be reduced to less than the recommended 2V full-scale swing with little loss of accuracy. The integrator output can swing to within 0.3V of either supply without loss of linearity. 6. DIFFERENTIAL REFERENCE The reference voltage can be generated anywhere within the power supply voltage of the converter. The main source of common mode error is a roll-over voltage caused by the reference capacitor losing or gaining charge to stray capacity on its nodes. If there is a large common mode voltage, the reference capacitor can gain charge (increase voltage) when called up to de-integrate a positive signal but lose charge (decrease voltage) when called up to de-integrate a negative input signal. This difference in reference for positive or negative input voltage will give a roll-over error. However, by selecting the reference capacitor such that it is large enough in comparison to the stray capacitance, this error can be held to less than 0.5 count worst case. (See Component Value Selection.) 7. ANALOG COMMON This pin is included primarily to set the common mode voltage for battery operation (SC7106) or for any system where the input signals are floating with respect to the power supply. The COMMON pin sets a voltage that is approximately 2.8V more negative than the positive supply. This is selected to give a minimum end-of -life battery voltage of about 6V. However, analog COMMON has some of the attributes of a reference voltage. When the total supply voltage is large enough to cause the zener to regulate (>7V), the COMMON voltage will have a low voltage coefficient (0.001%/V), low output impedance (≈15Ω), and a temperature coefficient typically less than 80ppm/°C. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 8 of 22 SC7106/7107 The limitations of the on chip reference should also be recognized, however. With the SC7107, the internal heating which results from the LED drivers can cause some degradation in performance. Due to their higher thermal resistance, plastic parts are poorer in this respect than ceramic. The combination of reference Temperature Coefficient (TC), internal chip dissipation, and package thermal resistance can increase noise near full scale from 25µV to 80µVp-p. Also the linearity in going from a high dissipation count such as 1000 (20 segments on) to a low dissipation count such as 1111(8 segments on) can suffer by a count or more. Devices with a positive TC reference may require several counts to pull out of an over-range condition. This is because over-range is a low dissipation mode, with the three least significant digits blanked. Similarly, units with a negative TC may cycle between over-range and a non-over-range count as the die alternately heats and cools. All these problems are of course eliminated if an external reference is used. The SC7106, with its negligible dissipation, suffers from none of these problems. In either case, an external reference can easily be added, as shown in Figure 4. Analog COMMON is also used as the input low return during auto-zero and de-integrate. If IN LO is different from analog COMMON, a common mode voltage exists in the system and is taken care of by the excellent CMRR of the converter. However, in some applications IN LO will be set at a fixed known voltage (power supply common for instance). In this application, analog COMMON should be tied to the same point, thus removing the common mode voltage from the converter. The same holds true for the reference voltage. If reference can be conveniently tied to analog COMMON, it should be since this removes the common mode voltage from the reference system. Within the IC, analog COMMON is tied to an N-Channel FET that can sink approximately 30mA of current to hold the voltage 2.8V below the positive supply (when a load is trying to pull the common line positive). However, there is only 10µA of source current, so COMMON may easily be tied to a more negative voltage thus overriding the internal reference. FIGURE 4. USING AN EXTERNAL REFERENCE 8. TEST The TEST pin serves two functions. On the SC7106 it is coupled to the internally generated digital supply through a 500Ω resistor. Thus it can be used as the negative supply for externally generated segment drivers such as decimal points or any other presentation the user may want to include on the LCD display. Figures 5 and 6 show such an application. No more than a 1mA load should be applied. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 9 of 22 SC7106/7107 FIGURE 5. SIMPLE INVERTER FOR FIXED FIGURE 6. EXCLUSIVE 'OR' GATE FOR DECIMAL DECIMAL POINT POINT DRIVE The second function is a "lamp test". When TEST is pulled high (to V+) all segments will be turned on and the display should read "1888". The TEST pin will sink about 15mA under these conditions. NOTE: In the lamp test mode, the segments have a constant DC voltage (no square-wave). This may burn the LCD display if maintained for extended periods. 9.DIGITAL SECTION Figures 7 and 8 show the digital section for the SC7106 and SC7107, respectively. In the SC7106, an internal digital ground is generated from a 6V Zener diode and a large P-Channel source follower. This supply is made stiff to absorb the relative large capacitive currents when the back plane (BP) voltage is switched. The BP frequency is the clock frequency divided by 800. For three readings/sec., this is a 60Hz square wave with a nominal amplitude of 5V. The segments are driven at the same frequency and amplitude and are in phase with BP when OFF, but out of phase when ON. In all cases negligible DC voltage exists across the segments. Figures 8 is the Digital Section of the SC7107. It is identical to the SC7106 except that the regulated supply and back plane drive have been eliminated and the segment drive has been increased from 2mA to 8mA, typical for instrument size common anode LED displays. Since the 1000 output (pin 19) must sink current from two LED segments it has twice the drive capability or 16mA. In both devices, the polarity indication is "on" for negative analog inputs. If IN LO and IN HI are reversed, this indication can be reversed also, if desired. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 10 of 22 SC7106/7107 FIGURE 7. SC7106 DIGITAL SECTION FIGURE 8. SC7107 DIGITAL SECTION HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 11 of 22 SC7106/7107 10. SYSTEM TIMING Figures 9 shows the clocking arrangement used in the SC7106 and SC7107. Two basic clocking arrangements can be used: 1) Figure 9A. An external oscillator connected to pin 40. 2) Figure 9B. An R-C oscillator using all three pins. The oscillator frequency is divided by four before it clocks the decade counters. It is then further divided to form the three convert-cycle phases. These are signal integrate (1000 counts), reference de-integrate (0 to 2000 counts ) and auto-zero (1000 to 3000 counts). For signals less than full scale, auto-zero gets the unused portion of reference de-integrate. This makes a complete measure cycle of 4,000 counts (16,000 clock pulses) independent of input voltage. For three readings/second, an oscillator frequency of 48kHz would be used. To achieve maximum rejection of 60Hz pickup, the signal integrate cycle should be a multiple of 60Hz. Oscillator frequencies of 240kHz, 120 kHz, 80 kHz, 60kHz, 48kHz, 40kHz, 331/3kHz, etc., should be selected. For 50Hz rejection, oscillator frequencies of 200kHz, 100kHz, 662/3kHz,50kHz, 40kHz, etc., would be suitable. Note that 40kHz (2.5 readings/second) will reject both 50Hz and 60Hz (also 400Hz and 440Hz). FIGURE 9. CLOCK CIRCUITS COMPONENT VALUE SELECTION 1. INTEGRATING RESISTOR Both the buffer amplifier and the integrator have a class A output stage with 100µA of quiescent current. They can supply 4µA of drive current with negligible nonlinearity. The integrating resistor should be large enough to remain in this very linear region over the input voltage range, but small enough that undue leakage requirements are not placed on the PC board. For 2V full scale, 470kΩ is near optimum and similarly a 47kΩ for a 200mV scale. 2.INTEGRATING CAPACITOR The integrating capacitor should be selected to give the maximum voltage swing that ensures tolerance buildup will not saturate the integrator swing (approximately. 0.3V from either supply). In the SC7106 or the SC7107, when the analog COMMON is used as a reference, a nominal +2V full-scale integrator swing is fine. For the SC7107 with +5V supplies and analog CIMMON tied to supply ground, a ±3.5V to +4V swing is nominal. For three readings/second (48kHz clock ) nominal values for CINT are 0.22µF and 0.10µF, respectively. Of course, if different oscillator frequencies are used, these values should be changed in inverse proportion to maintain the same output swing. An additional requirement of the integrating capacitor is that it must have a low dielectric absorption to prevent roll-over errors. While other types of capacitors are adequate for this application, polypropylene capacitors give undetectable errors at reasonable cost. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 12 of 22 SC7106/7107 3.AUTO-ZERO CAPACITOR The size of the auto-zero capacitor has some influence on the noise of the system. For 200mV full scale where noise is very important, a 0.47µF capacitor is recommended. On the 2V scale, a 0.047µF capacitor increases the speed of recovery from overload and is adequate for noise on this scale. 4.REFERENCE CAPACITOR A 0.1µF capacitor gives good results in most applications. However, where a large common mode voltage exists (i.e., the REF LO pin is not at analog COMMON) and a 200mV scale is used, a larger value is required to prevent roll-over error. Generally 1µF will hold the roll-over error to 0.5 count in this instance. 5.OSCILLATOR COMPONENTS For all ranges of frequency a 100kΩ resistor is recommended and the capacitor is selected from the equation: f=0.45/RC, for 48kHz clock (3 Readings/sec), C=100pF. 6.REFERENCE VOLTAGE The analog input required to generate full-scale output (2000 counts) is: VIN=2VREF. Thus, for the 200mV and 2V scale, VREF should equal 100mV and 1V, respectively. However, in many applications where the A/D is connected to a transducer, there will exist a scale factor other than unity between the input voltage and the digital reading. For instance, in a weighing system, the designer might like to have a full-scale reading when the voltage from the transducer is 0.662V. Instead of dividing the input down to 200mV, the designer should use the input voltage directly and select VREF=0.341V. Suitable values for integrating resistor and capacitor would be 120kΩ and 0.22µF. This makes the system slightly quieter and also avoids a divider network on the input. The SC7107 with ±5V supplies can accept input signals up to ±4V. Another advantage of this system occurs when a digital reading of zero is desired for VIN≠0. Temperature and weighing systems with a variable fare are examples. This offset reading can be conveniently generated by connecting the voltage transducer between IN HI and COMMON and the variable (or fixed) offset voltage between COMMON and IN LO. 7.SC7107 POWER SUPPLIES The SC7107 is designed to work from ±5V supplies. However, if a negative supply is not available, it can be generated from the clock output with 2 diodes, 2 capacitors, and an inexpensive IC. Figure 10 shows this application. In fact, in selected applications no negative supply is required. The conditions to use a single +5V supply are: 1) The input signal can be referenced to the center of the common mode range of the converter. 2) The signal is less than ±1.5V. 3) An external reference is used. FIGURE 10. GENERATING NEGATIVE SUPPLY FROM +5V HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 13 of 22 SC7106/7107 TYPICAL APPLICATIONS The SC7106 and SC7107 may be used in a wide variety of configurations. The circuits which follow show some of the possibilities, and serve to illustrate the exceptional versatility of these A/D converters. Values shown are for 200mV full scale, 3 Values readings/sec., floating supply voltage (9V battery). readings/sec. IN LO may be tied to either COMMON shown are for 200mV full scale, 3 for inputs floating with respect to supplies, or GND for single ended inputs. (See discussion under Analog COMMON.) FIGURE 11. SC7106 USING THE INTERNAL FIGURE 12. SC7107 USING THE INTERNAL REFERENCE REFERENCE HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 14 of 22 SC7106/7107 TYPICAL APPLICATIONS(CONTINUED) OSC1 40 OSC2 39 OSC3 38 TEST 37 REF HI 36 REF LO 35 TO PIN1 100K 100pF SET VREF=100mV +5V 1K CREF+ 100K 34 CREF- 33 COMMON 32 IN HI 31 IN LO 30 A-Z 29 BUFF 28 INT 27 V- 26 G2 25 C3 24 A3 23 G3 22 GND 21 6.8V 0.1 F 1M + 0.01 F IN - 0.47 F 47K 0.22 F -5V TO DISPLAY IN LO is tied to supply COMMON establishing the Since low TC zeners have breakdown voltages~6.8V, correct common mode voltage. If COMMON is not diode must be placed across the total supply (10V). shorted to GND, the input voltage may float with As in the case of Figure 14, IN LO may be tied to respect to the power supply and COMMON acts as a either COMMON or GND. pre-regulator for the reference. If COMMON is shorted to GND, the input is single ended (referred to supply GND) and the pre-regulator is overridden. FIGURE 13. SC7107 WITH AN EXTERNAL BAND- FIGURE 14. SC7107 WITH ZENER DIODE GAP REFERENCE (1.2V TYPE) REFERENCE HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 15 of 22 SC7106/7107 TYPICAL APPLICATIONS(CONTINUED) An external reference must be used in this application, since the voltage between V+ and v- is insufficient for correct operation of the internal reference. FIGURE 15. SC7106 AND SC7107: RECOMMENDED COMPONENT VALUES FOR 2V FIGURE 16. SC7107 OPERATED FROM SINGLE +5V FULL SCALE HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 16 of 22 SC7106/7107 TYPICAL APPLICATIONS(CONTINUED) OSC1 40 OSC2 39 OSC3 38 TEST 37 REF HI 36 REF LO 35 CREF+ 34 CREF- 33 COMMON 32 IN HI 31 IN LO 30 A-Z 29 BUFF 28 INT 27 V- 26 G2 25 C3 24 A3 23 G3 22 GND 21 TO PIN1 V+ 100K 100pF 0.1 F 0.47 F 47K 0.22¦ÌF TO DISPLAY The resistor values within the bridge are determined A by the desired sensitivity. temperature coefficient of about -2mV/°C. Calibration silicon diode-connected transistor has a is achieved by placing the sensing transistor in ice water and adjusting the zeroing potentiometer for a 00.0 reading. The sensor should then be placed in boiling water and the scale-factor potentiometer adjusted for a 100.0 reading. FIGURE 17. SC7107 MEASUREING RATIOMETRIC FIGURE 18. SC7106 USED AS A DIGITAL VALUES OF QUAD LOAD CELL CENTIGRADE THERMOMETOR HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 17 of 22 SC7106/7107 TYPICAL APPLICATIONS(CONTINUED) FIGURE 19. CIRCUIT FOR DEVELOPING FIGURE 20. CIRCUIT FOR DEVELOPING UNDERRANGE AND OVERRANGE SIGNAL FROM UNDERRANGE AND OVERRANGE SIGNAL FROM SC7106 OUTPUTS SC7107 OUTPUTS HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 18 of 22 SC7106/7107 TYPICAL APPLICATIONS(CONTINUED) Test is used as a common-mode reference level to ensure compatibility with most op amps. FIGURE 21. AC TO DC CONVERTER WITH SC7106 FIGURE 22. DISPLAY BUFFERING FOR INCREASED DRIVE CURRENT HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 19 of 22 SC7106/7107 PACKAGE OUTLINE 0.5MIN 15.24±0.25 UNIT: mm 3.7±0.1 5.1 MAX 14.0±0.3 DIP-40-600-2.54 QFP-44-10X10-0.8 HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn UNIT: mm REV:1.2 2006.02.27 Page 20 of 22 SC7106/7107 HANDLING MOS DEVICES: Electrostatic charges can exist in many things. All of our MOS devices are internally protected against electrostatic discharge but they can be damaged if the following precautions are not taken: • Persons at a work bench should be earthed via a wrist strap. • Equipment cases should be earthed. • All tools used during assembly, including soldering tools and solder baths, must be earthed. • MOS devices should be packed for dispatch in antistatic/conductive containers. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2006.02.27 Page 21 of 22