CS8191XDWF20 View Datasheet(PDF) - ON Semiconductor
Part Name
Description
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CS8191XDWF20 Datasheet PDF : 12 Pages
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CS8191
Battery
D1
R1
1.0 A, 3.9,
600 PIV 500 mW D2
50 V,
500 mW Zener
GND
R2
10 kΩ
Typical Speedometer
Input
C3
0.1 µF
C1
0.1 µF
1 VCC
VREG
BIAS
F/VOUT
CP+
CP–
GND
GND
COS–
GND
GND
COS+
SINE– SINE+
FREQIN SQOUT
SINE
C4
0.47 µF +
RT
Trim Resistor,
+/–20 PPM/°C
R4
1.0 kΩ
CCP
0.0033 µF,
+/–30 PPM/°C
R3
3.0 kΩ
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
Maximum meter Deflection = 270°
Maximum Input Frequency = 350 Hz
1. Select RT and CCP
Q + 970 FREQ CCP RT
Let CCP = 0.0033 µF, find RT
RT + 970
270°
350 Hz 0.0033 mF
RT + 243 kW
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
VREG * 0.7
3.3 kW
V
+
1.90
mA
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.
T + 10%
1
350
Hz
+
285ms
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.
C4
+
CCP(VREG *
DVMAX
0.7
V)
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.
http://onsemi.com
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