CS8191 Precision Air-Core Tach/Speedo Driver with Short Circuit Protection The CS8191 is specifically designed for use with 4 quadrant air–core meter movements. The IC includes an input comparator for sensing input frequency such as vehicle speed or engine RPM, a charge pump for frequency to voltage conversion, a bandgap reference for stable operation and a function generator with sine and cosine amplifiers that differentially drive the meter coils. The CS8191 has a higher torque output and better output signal symmetry than other competitive parts (CS289, and LM1819). It is protected against short circuit and overvoltage (60 V) fault conditions. Enhanced circuitry permits functional operation down to 8.0 V. Features Direct Sensor Input High Output Torque Wide Output Voltage Range High Impedance Inputs Accurate Down to 10 V VCC Fault Protection – Overvoltage – Short Circuit – Low Voltage Operation • Internally Fused Leads in DIP–16 and SO–20L Packages http://onsemi.com 20 16 1 1 SO–20L DWF SUFFIX CASE 751D DIP–16 NF SUFFIX CASE 648 • • • • • • PIN CONNECTIONS AND MARKING DIAGRAM DIP–16 1 16 VCC F/VOUT CP+ CP– CS8191XNF16 AWLYYWW VREG BIAS GND GND COS– SINE– GND GND COS+ SINE+ FREQIN SQOUT 1 A WL, L YY, Y WW, W SO–20L CS–8191 AWLYYWW VCC VREG BIAS NC GND GND NC COS– SIN– FREQIN 20 F/VOUT CP+ CP– NC GND GND NC COS+ SIN+ SQOUT = Assembly Location = Wafer Lot = Year = Work Week ORDERING INFORMATION Semiconductor Components Industries, LLC, 2001 March, 2001 – Rev. 4 1 Device Package Shipping CS8191XNF16 DIP–16 25 Units/Rail CS8191XDWF20 SO–20L 37 Units/Rail CS8191XDWFR20 SO–20L 1000 Tape & Reel Publication Order Number: CS8191/D CS8191 BIAS Charge Pump CP+ F/VOUT + - CP– SQOUT Input Comp. VREG + - FREQIN Voltage Regulator GND GND VREG 7.0 V GND GND SINE+ COS+ COS Output + + Function Generator + - + - SINE Output SINE– COS– High Voltage, Short Circuit Protection VCC Figure 1. Block Diagram ABSOLUTE MAXIMUM RATINGS* Rating Value Unit 60 24 V V Operating Temperature Range –40 to +105 °C Junction Temperature Range –40 to +150 °C Storage Temperature Range –55 to +165 °C 4.0 kV 260 peak 230 peak °C °C Supply Voltage, VCC < 100 ms Pulse Transient Continuous Elecrostatic Discharge (Human Body Model) Lead Temperature Soldering: Wave Solder (through hole styles only) (Note 1.) Reflow: (SMD styles only) (Note 2.) 1. 10 seconds maximum. 2. 60 second maximum above 183°C. *The maximum package power dissipation must be observed. http://onsemi.com 2 CS8191 ELECTRICAL CHARACTERISTICS (–40°C ≤ TA ≤ 105°C, 8.0 V ≤ VCC ≤ 16 V, unless otherwise specified.) Characteristic Test Conditions Min Typ Max Unit – 70 125 mA – 8.0 13.1 16 V Positive Input Threshold – 2.4 2.7 3.0 V Negative Input Threshold – 2.0 2.3 – V Input Hysteresis – 200 400 1000 mV – –2.0 ±10 µA 0 – 20 kHz –1.0 – VCC V Supply Voltage Section ICC Supply Current VCC = 16 V, –40°C, No Load VCC Normal Operation Range Input Comparator Section Input Bias Current (Note 3.) 0 V ≤ VIN ≤ 8.0 V Input Frequency Range – Input Voltage Range in series with 1.0 kΩ Output VSAT ICC = 10 mA – 0.15 0.40 V Output Leakage VCC = 7.0 V – – 10 µA – 2.0 – – V Output Voltage – 6.50 7.00 7.50 V Output Load Current – – – 10 mA Logic 0 Input Voltage Voltage Regulator Section Output Load Regulation 0 to 10 mA – 10 50 mV Output Line Regulation 8.0 V ≤ VCC ≤ 16 V – 20 150 mV Power Supply Rejection VCC = 13.1 V, 1.0 VP/P 1.0 kHz 34 46 – dB Charge Pump Section Inverting Input Voltage – 1.5 2.0 2.5 V Input Bias Current – – 40 150 nA VBIAS Input Voltage – 1.5 2.0 2.5 V – 0.7 1.1 V –0.10 0.28 +0.70 % Non Invert. Input Voltage IIN = 1.0 mA Linearity (Note 4.) @ 0, 87.5, 175, 262.5, + 350 Hz F/VOUT Gain @ 350 Hz, CCP = 0.0033 µF, RT = 243 kΩ 7.0 10 13 mV/Hz Norton Gain, Positive IIN = 15 µA 0.9 1.0 1.1 I/I Norton Gain, Negative IIN = 15 µA 0.9 1.0 1.1 I/I Function Generator Section: –40C TA 85°C, VCC = 13.1 V unless otherwise noted. Differential Drive Voltage (VCOS+ – VCOS–) 10 V ≤ VCC ≤ 16 V Θ = 0° 7.5 8.0 8.5 V Differential Drive Voltage (VSIN+ – VSIN–) 10 V ≤ VCC ≤ 16 V Θ = 90° 7.5 8.0 8.5 V Differential Drive Voltage (VCOS+ – VCOS–) 10 V ≤ VCC ≤ 16 V Θ = 180° –8.5 –8.0 –7.5 V Differential Drive Voltage (VSIN+ – VSIN–) 10 V ≤ VCC ≤ 16 V Θ = 270° –8.5 –8.0 –7.5 V 3. Input is clamped by an internal 12 V Zener. 4. Applies to % of full scale (270°). http://onsemi.com 3 CS8191 ELECTRICAL CHARACTERISTICS (continued) (–40°C ≤ TA ≤ 105°C, 8.0 V ≤ VCC ≤ 16 V, unless otherwise specified.) Characteristic Test Conditions Min Typ Max Unit Function Generator Section: –40C TA 85°C, VCC = 13.1 V unless otherwise noted. (continued) Differential Drive Load 10 V ≤ VCC ≤ 16 V, –40°C 25°C 105°C Zero Hertz Output Voltage – 178 239 314 – – – – – – Ω Ω Ω –0.08 0 +0.08 V Function Generator Error (Note 5.) Reference Figures 2, 3, 4, 5 Θ = 0° to 225° Θ = 226° to 305° –2.0 –3.0 0 0 +2.0 +3.0 deg deg Function Generator Error 13.1 V ≤ VCC ≤ 16 V –1.0 0 +1.0 deg Function Generator Error 13.1 V ≤ VCC ≤ 10 V –1.0 0 +1.0 deg Function Generator Error 13.1 V ≤ VCC ≤ 8.0 V –7.0 0 +7.0 deg Function Generator Error 25°C ≤ TA ≤ 80°C –2.0 0 +2.0 deg Function Generator Error 25°C ≤ TA ≤ 105°C –4.0 0 +4.0 deg Function Generator Error –40°C ≤ TA ≤ 25°C –2.0 0 +2.0 deg Function Generator Gain TA = 25°C, Θ vs F/VOUT, 60 77 95 °/V 5. Deviation from nominal per Table 1 after calibration at 0° and 270°. PIN FUNCTION DESCRIPTION PACKAGE PIN # DIP–16 SO–20L PIN SYMBOL 1 1 VCC Ignition or battery supply voltage. 2 2 VREG Voltage regulator output. 3 3 BIAS Test point or zero adjustment. 4, 5, 12, 13 5, 6, 15, 16 GND Ground Connections. 6 8 COS– Negative cosine output signal. 7 9 SIN– Negative sine output signal. 8 10 FREQIN Speed or RPM input signal. 9 11 SQOUT Buffered square wave output signal. 10 12 SIN+ Positive sine output signal. 11 13 COS+ Positive cosine output signal. 14 18 CP– Negative input to charge pump. 15 19 CP+ Positive input to charge pump. 16 20 F/VOUT – 4, 7, 14, 17 NC FUNCTION Output voltage proportional to input signal frequency. No connection. http://onsemi.com 4 CS8191 TYPICAL PERFORMANCE CHARACTERISTICS FVOUT 2.0 V 2.0 FREQ CCP RT (VREG 0.7 V) 6 5 4 3 2 1 0 –1 –2 –3 –4 –5 –6 –7 7 6 COS F/V Output (V) Output Voltage (V) 7 5 4 3 2 1 SIN 0 45 90 135 180 225 Degrees of Deflection (°) 270 0 315 0 Figure 2. Function Generator Output Voltage vs. Degrees of Deflection 135 180 225 270 Frequency/Output Angle (°) Angle –7.0 V 7.0 V Deviation (°) Θ 1.00 0.75 0.50 0.25 0.00 –0.25 –0.50 (VCOS+) – (VCOS–) –0.75 –1.00 –1.25 –7.0 V –1.50 0 Figure 4. Output Angle in Polar Form 45 90 225 135 180 Theoretical Angle (°) 270 Figure 5. Nominal Output Deviation 45 Ideal Angle (Degrees) 40 35 30 25 20 Ideal Degrees 15 Nominal Degrees 10 5 0 1 5 9 13 315 1.50 1.25 7.0 V SIN VSIN VVCOS VCOS 90 Figure 3. Charge Pump Output Voltage vs. Output Angle (VSINE+) – (VSINE–) ARCTAN 45 17 25 29 21 Nominal Angle (Degrees) 33 37 Figure 6. Nominal Angle vs. Ideal Angle (After Calibrating at 180) http://onsemi.com 5 41 45 315 CS8191 Table 1. Function Generator Output Nominal Angle vs. Ideal Angle (After Calibrating at 270) Ideal Degrees Nominal Degrees Ideal Degrees Nominal Degrees Ideal Degrees Nominal Degrees Ideal Degrees Nominal Degrees Ideal Degrees Nominal Degrees Ideal Degrees Nominal Degrees 0 0 17 17.98 34 33.04 75 74.00 160 159.14 245 244.63 1 1.09 18 18.96 35 34.00 80 79.16 165 164.00 250 249.14 2 2.19 19 19.92 36 35.00 85 84.53 170 169.16 255 254.00 3 3.29 20 20.86 37 36.04 90 90.00 175 174.33 260 259.16 4 4.38 21 21.79 38 37.11 95 95.47 180 180.00 265 264.53 5 5.47 22 22.71 39 38.21 100 100.84 185 185.47 270 270.00 6 6.56 23 23.61 40 39.32 105 106.00 190 190.84 275 275.47 7 7.64 24 24.50 41 40.45 110 110.86 195 196.00 280 280.84 8 8.72 25 25.37 42 41.59 115 115.37 200 200.86 285 286.00 9 9.78 26 26.23 43 42.73 120 119.56 205 205.37 290 290.86 10 10.84 27 27.07 44 43.88 125 124.00 210 209.56 295 295.37 11 11.90 28 27.79 45 45.00 130 129.32 215 214.00 300 299.21 12 12.94 29 28.73 50 50.68 135 135.00 220 219.32 305 303.02 13 13.97 30 29.56 55 56.00 140 140.68 225 225.00 14 14.99 31 30.39 60 60.44 145 146.00 230 230.58 15 16.00 32 31.24 65 64.63 150 150.44 235 236.00 16 17.00 33 32.12 70 69.14 155 154.63 240 240.44 Note: Temperature, voltage and nonlinearity not included. CIRCUIT DESCRIPTION and APPLICATION NOTES The CS8191 is specifically designed for use with air–core meter movements. It includes an input comparator for sensing an input signal from an ignition pulse or speed sensor, a charge pump for frequency to voltage conversion, a bandgap voltage regulator for stable operation, and a function generator with sine and cosine amplifiers to differentially drive the meter coils. From the partial schematic of Figure 7, the input signal is applied to the FREQIN lead, this is the input to a high impedance comparator with a typical positive input threshold of 2.7 V and typical hysteresis of 0.4 V. The output of the comparator, SQOUT, is applied to the charge pump input CP+ through an external capacitor CCP. When the input signal changes state, CCP is charged or discharged through R3 and R4. The charge accumulated on CCP is mirrored to C4 by the Norton Amplifier circuit comprising of Q1, Q2 and Q3. The charge pump output voltage, F/VOUT, ranges from 2.0 V to 6.3 V depending on the input signal frequency and the gain of the charge pump according to the formula: on–chip amplifier and function generator circuitry. The various trip points for the circuit (i.e., 0°, 90°, 180°, 270°) are determined by an internal resistor divider and the bandgap voltage reference. The coils are differentially driven, allowing bidirectional current flow in the outputs, thus providing up to 305° range of meter deflection. Driving the coils differentially offers faster response time, higher current capability, higher output voltage swings, and reduced external component count. The key advantage is a higher torque output for the pointer. The output angle, Θ, is equal to the F/V gain multiplied by the function generator gain: AFV AFG, where: AFG 77°V(typ) The relationship between input frequency and output angle is: AFG 2.0 FREQ CCP RT (VREG 0.7 V) FVOUT 2.0 V 2.0 FREQ CCP RT (VREG 0.7 V) or, RT is a potentiometer used to adjust the gain of the F/V output stage and give the correct meter deflection. The F/V output voltage is applied to the function generator which generates the sine and cosine output voltages. The output voltage of the sine and cosine amplifiers are derived from the 970 FREQ CCP RT The ripple voltage at the F/V converter’s output is determined by the ratio of CCP and C4 in the formula: V http://onsemi.com 6 CCP(VREG 0.7 V) C4 CS8191 will reduce the ripple on the F/V output but will also increase the response time. An increase in response time causes a very slow meter movement and may be unacceptable for many applications. Ripple voltage on the F/V output causes pointer or needle flutter especially at low input frequencies. The response time of the F/V is determined by the time constant formed by RT and C4. Increasing the value of C4 VREG 2.0 V F/VOUT + R3 – 0.25 V + SQOUT FREQIN VC(t) Q3 CP– RT – R4 CCP CP+ C4 + Q1 QSQUARE Q2 – 2.7 V Figure 7. Partial Schematic of Input and Charge Pump T tDCHG tCHG VCC FREQIN 0 VREG SQOUT F to V 0 ICP+ VCP+ 0 Figure 8. Timing Diagram of FREQIN and ICP http://onsemi.com 7 CS8191 D1 R1 1.0 A, 600 PIV 3.9, 500 mW 1 VCC D2 50 V, 500 mW Zener C1 0.1 µF F/VOUT VREG CP+ BIAS CP– CS8191 Battery GND GND GND R2 RT Trim Resistor, +/–20 PPM/°C + GND R4 1.0 kΩ GND COS– COS+ SINE– SINE+ FREQIN 10 kΩ C4 0.47 µF R3 3.0 kΩ CCP 0.0033 µF, +/–30 PPM/°C SQOUT SINE C3 0.1 µF Typical Speedometer Input COSINE Air Core Gauge Speedometer Notes: 1. The product of C4 and RT have a direct effect on gain and therefore directly affect temperature compensation. 2. C4 Range; 20 pF to 0.2 µF. 3. R4 Range; 100 kΩ to 500 kΩ. 4. The IC must be protected from transients above 60 V and reverse battery conditions. 5. Additional filtering on the FREQIN lead may be required. 6. Gauge coil connections to the IC must be kept as short as possible (≤ 3.0 inch) for best pointer stability. Figure 9. Speedometer or Tachometer Application Design Example CCP must charge and discharge fully during each cycle of the input signal. Time for one cycle at maximum frequency is 2.85 ms. To ensure that CCP is charged, assume that the (R3 + R4) CCP time constant is less than 10% of the minimum input period. Maximum meter Deflection = 270° Maximum Input Frequency = 350 Hz 1. Select RT and CCP 970 FREQ CCP RT T 10% Let CCP = 0.0033 µF, find RT RT 1 285s 350 Hz Choose R4 = 1.0 kΩ. Discharge time: tDCHG= R3 × CCP = 3.3 kΩ × 0.0033 µF = 10.9 µs Charge time: tCHG = (R3 + R4)CCP = 4.3 kΩ. × 0.0033 µF = 14.2 µs 3. Determine C4 C4 is selected to satisfy both the maximum allowable ripple voltage and response time of the meter movement. 270° 970 350 Hz 0.0033 F RT 243 k RT should be a 250 kΩ potentiometer to trim out any inaccuracies due to IC tolerances or meter movement pointer placement. 2. Select R3 and R4 Resistor R3 sets the output current from the voltage regulator. The maximum output current from the voltage regulator is 10 mA. R3 must ensure that the current does not exceed this limit. Choose R3 = 3.3 kΩ The charge current for CCP is C4 CCP(VREG 0.7 V) VMAX With C4 = 0.47 µF, the F/V ripple voltage is 44 mV. Figure 10 shows how the CS8191 and the CS8441 are used to produce a Speedometer and Odometer circuit. VREG 0.7 V 1.90 mA 3.3 k http://onsemi.com 8 CS8191 D1 R1 1.0 A, 600 PIV 3.9, 500 mW 1 VCC D2 50 V, 500 mW Zener VREG CP+ BIAS CP– GND C1 0.1 µF GND F/VOUT CS8191 Battery GND R2 RT Trim Resistor, +/–20 PPM/°C + GND R4 1.0 kΩ GND COS– COS+ SINE– SINE+ FREQIN 10 kΩ C4 0.47 µF CCP 0.0033 µF, +/–30 PPM/°C SQOUT SINE C3 0.1 µF Typical Speedometer Input COSINE C2 10 µF Air Core Gauge Speedometer 1 CS8441 Air Core Stepper Motor 200 Ω Odometer Notes: 1. The product of C4and RT have a direct effect on gain and therefore directly affect temperature compensation. 2. C4 Range; 20 pF to 0.2 µF. 3. R4 Range; 100 kΩ to 500 kΩ. 4. The IC must be protected from transients above 60 V and reverse battery conditions. 5. Additional filtering on the FREQIN lead may be required. 6. Gauge coil connections to the IC must be kept as short as possible (≤ 3.0 inch) for best pointer stability. Figure 10. Speedometer With Odometer or Tachometer Application http://onsemi.com 9 R3 3.0 kΩ CS8191 In some cases a designer may wish to use the CS8191 only as a driver for an air–core meter having performed the F/V conversion elsewhere in the circuit. Figure 11 shows how to drive the CS8191 with a DC voltage ranging from 2.0 V to 6.0 V. This is accomplished by forcing a voltage on the F/VOUT lead. The alternative scheme shown in Figure 12 uses an external op amp as a buffer and operates over an input voltage range of 0 V to 4.0 V. Figures 11 and 12 are not temperature compensated. CS8191 100 kΩ 100 kΩ VIN 0 V to 4.0 V DC VREG 100 kΩ + BIAS + – 10 kΩ – CP– F/VOUT CS8191 100 kΩ CP– – 100 kΩ + 10 kΩ VIN 2.0 V to 6.0 V DC N/C Figure 12. Driving the CS8191 from an External DC Voltage Using an Op Amp Buffer BIAS F/VOUT Figure 11. Driving the CS8191 from an External DC Voltage http://onsemi.com 10 CS8191 PACKAGE DIMENSIONS DIP–16 NF SUFFIX CASE 648–08 ISSUE R NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. 3. DIMENSION L TO CENTER OF LEADS WHEN FORMED PARALLEL. 4. DIMENSION B DOES NOT INCLUDE MOLD FLASH. 5. ROUNDED CORNERS OPTIONAL. –A– 16 9 1 8 B F C DIM A B C D F G H J K L M S L S –T– SEATING PLANE K H G D M J 16 PL 0.25 (0.010) T A M M INCHES MIN MAX 0.740 0.770 0.250 0.270 0.145 0.175 0.015 0.021 0.040 0.70 0.100 BSC 0.050 BSC 0.008 0.015 0.110 0.130 0.295 0.305 0 10 0.020 0.040 MILLIMETERS MIN MAX 18.80 19.55 6.35 6.85 3.69 4.44 0.39 0.53 1.02 1.77 2.54 BSC 1.27 BSC 0.21 0.38 2.80 3.30 7.50 7.74 0 10 0.51 1.01 SO–20L DWF SUFFIX CASE 751D–05 ISSUE F 20 11 X 45 h 1 10 20X B B 0.25 DIM A A1 B C D E e H h L M T A S B S A L H M E 0.25 10X NOTES: 1. DIMENSIONS ARE IN MILLIMETERS. 2. INTERPRET DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994. 3. DIMENSIONS D AND E DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 PER SIDE. 5. DIMENSION B DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE PROTRUSION SHALL BE 0.13 TOTAL IN EXCESS OF B DIMENSION AT MAXIMUM MATERIAL CONDITION. A B M D 18X e A1 SEATING PLANE MILLIMETERS MIN MAX 2.35 2.65 0.10 0.25 0.35 0.49 0.23 0.32 12.65 12.95 7.40 7.60 1.27 BSC 10.05 10.55 0.25 0.75 0.50 0.90 0 7 C T PACKAGE THERMAL DATA DIP–16 Parameter SO–20L Unit RΘJC Typical 15 9 °C/W RΘJA Typical 50 55 °C/W http://onsemi.com 11 CS8191 ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. 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