IL8190

TECHNICAL DATA
PRECISION AIR - CORE TACH / SPEEDO DRIVER
WITH RETURN TO ZERO
IL8190
DESCRIPTION
The IL8190 is specifically designed for use with air–
core meter movements. The IC provides all the functions
necessary for an analog tachometer or speedometer. The
IL8190 takes a speed sensor input and generates sine
and cosine related output signals to differentially drive an
air–core meter.
ORDERING INFORMATION
IL8190N Plastic DIP
IL8190DW SOIC
TA = -40 to 105 C
ORDERING INFORMATION
FEATURES

Direct Sensor Input

High Output Torque

Low Pointer Flutter

High Input Impedance

Overvoltage Protection

Return to Zero
Device
Operating Temperature
Range
Package
Packing
IL8190N
IL8190DW
IL8190DWT
TA = -40 to 105 C
DIP-16
SOP-20
SOP-20
Tube
Tube
T&R
PIN ASSIGNMENT
DIP-16
SOP-20
December, 2012, Rev. 02
IL8190
ABSOLUTE MAXIMUM RATINGS*
Symbol
Parameter
Value
100 ms Pulse Transient
60
Continuous
24
Unit
VCC
Supply Voltage
Topr
Operating Temperature
-40 to +105
C
TJ
Junction Temperature
-40 to +150
°C
Tstg
Storage Temperature
-60 to +165
°C
260 peak
C
4.0
kV
Lead Temperature Soldering: Wave Solder (through
hole styles only) (Note)
TL
ESD (Human Body Model)
V
Note: 10 seconds maximum.
*The maximum package power dissipation must be observed.
** Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device.
These are stress ratings only and functional operation of the device at these or any other conditions beyond those
indicated under “recommended operating conditions” is not implied.
Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
BLOCK DIAGRAM
BIAS
VOUT/F
+
CP+
Churge Pump
CP-
SQOUT
Input
Comp.
FREQIN
VREG
+
Voltage
Regulator
GND
GND
VREG
7.0 V
GND
GND
COS+
SIN+
+
COS
Output +
Func.
Gen.
+
COS-
VCC
+
SINE
Output
SIN-
High Voltage
Protection
December, 2012, Rev. 02
IL8190
PIN DISCRIPTIONS
Pin No.
Symbol
Function
DIP-16
SOP-20
1
1
CP+
2
2
SQOUT
3
3
FREQIN
4, 5, 12,
13
4-7, 14-17
GND
Ground Connections
6
8
COS+
Positive cosine output signal
7
9
COS–
Negative cosine output signal
8
10
VCC
9
11
BIAS
Test point or zero adjustment
10
12
SIN–
Negative sine output signal
11
13
SIN+
Positive sine output signal
14
18
VREG
Voltage regulator output
15
19
VOUT/F
16
20
CP–
Positive input to charge pump
Buffered square wave output signal
Speed or RPM input signal
Ignition or battery supply voltage
Output voltage proportional to input signal
frequency
Negative input to charge pump
December, 2012, Rev. 02
IL8190
ELECTRICAL CHARACTERISTICS
(-40°C ≤ TA ≤ 85°C, 8.5 V ≤ VCC ≤ 16 V, unless otherwise specified)
Symbol
Parameter
Test Condition
Min
Typ
Max
Unit
66
125
mA
13.1
16
V
Supply Voltage Section
ICC
Supply Current
VCC
Normal Operation Range
VCC = 16 V, No Load
8.5
Input Comparator Section
VТН
Positive Input Threshold
1.0
2.1
3.0
V
VH
Input Hysteresis
200
470
–
mV
IIB1
Input Bias Current (Note
1)
–
-4
-80
A
FIN
Input Frequency Range
0
-
20
kHz
VIN
Input Voltage Range
in series with1.0 k
-1.0
-
VCC
V
VSAT
Output VSAT
IO = 10 mA
–
0.10
0.40
V
ISING
Output Leakage
VO = 7.0 V
–
0.02
10
A
VCC-TH
Low VCC Disable
Threshold
7.0
8.0
8.5
V
Logic 0 Input Voltage
1.0
1.6
–
V
6.25
7.00
7.50
V
-
-
10
mA
VL
0 V ≤ VIN ≤ 8.0 V
Voltage Regulator Section
VREF
IO
Output Voltage
Output Load Current
VREF-LOAD Output Load Regulation
0 to 10 mA
–
4
50
mV
VREF-LINE Output Line Regulation
8.5 V ≤ VCC ≤ 16 V
–
30
150
mV
VCC = 13.1 V, 1.0 VP/P 1.0 kHz
34
46
–
dB
1.5
2.1
2.5
V
PRS
Power Supply Rejection
Charge Pump Section
UINV
Inverting Input Voltage
IIB2
Input Bias Current
–
35
150
nA
VBIAS
VBIAS Input Voltage
1.5
2.1
2.5
V
UNINV
Non Invert. Input Voltage
IIN = 1.0 mA
–
0.6
1.1
V
LK
Linearity (Note 2)
@ 0; 87.5; 175; 262.5;
+ 350 Hz
–0.10
0.27
+0.70
%
K
VOUT/F Gain
@ 350 Hz, CCP = 0.0033 F,
RT = 243 k
7.0
11
13
mV/H
z
GN+
Norton Gain, Positive
IIN = 15 A
0.9
1.0
1.1
GN-
Norton Gain, Negative
IIN = 15 A
0.9
1.0
1.1
December, 2012, Rev. 02
IL8190
ELECTRICAL CHARACTERISTICS (continued)
(-40°C ≤ TA ≤ 85°C, 8.5 V ≤ VCC ≤ 16 V, unless otherwise specified)
Symbol
Parameter
Test Condition
Min
Typ
Max
Unit
Function Generator Section: –40°C ≤ TA ≤ 85°C, VCC = 13.1 V unless otherwise noted
VCC-TH1
Return to Zero Threshold
TA = 25°C
5.2
6.0
7.0
V
Differential Drive Voltage
(VCOS+ – VCOS–)
Differential Drive Voltage
(VSIN+ – VSIN–)
Differential Drive Voltage
(VCOS+ – VCOS–)
Differential Drive Voltage
(VSIN+ – VSIN–)
8.5 V ≤ VCC ≤ 16 V, = 0°
5.5
6.5
7.5
V
8.5 V ≤ VCC ≤ 16 V,  = 90°
5.5
6.5
7.5
V
8.5 V ≤ VCC ≤ 16 V,
 = 180°
8.5 V ≤ VCC ≤ 16 V,
 = 270°
–7.5
-6.5
–5.5
V
–7.5
-6.5
–5.5
V
IOUT
Differential Drive Current
8.5 V ≤ VCC ≤ 16 V
–
33
42
mA

Zero Hertz Output Angle
-1.5
0
1.5
deg
V(COS+-COS-)
V (SIN+-SIN-)
V (COS+-COS-)
V (SIN+-SIN-)
/V
Function Generator Error
(Note 3) Reference
Figures 1, 2, 3, 4
VCC = 13.1 V
 = 0° to 305°
-2.0
0
+2.0
deg
Function Generator Error
13.1 V ≤ VCC ≤ 16 V
-2.5
0
+2.5
deg
Function Generator Error
13.1 V ≤ VCC ≤ 11 V
-1.0
0
+1.0
deg
Function Generator Error
13.1 V ≤ VCC ≤ 9.0 V
-3.0
0
+3.0
deg
Function Generator Error
25°C ≤ TA ≤ 80°C
-3.0
0
+3.0
deg
Function Generator Error
25°C ≤ TA ≤ 105°C
-5.5
0
+5.5
deg
Function Generator Error
-40°C ≤ TA ≤ 25°C
-3.0
0
+3.0
deg
Function Generator Gain
TA = 25°C,  vs VOUT/F
60
77
95
°/V
Notes:
1. Input is clamped by an internal 12 V Zener.
2. Applies to % of full scale (270°).
3. Deviation from nominal per Table 1 after calibration at 0° and 270°.
December, 2012, Rev. 02
IL8190
Output Voltage (V)
TYPICAL PERFOMANCE CHARACTERISTICS
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
VOUT/F = 2.0 V+2.0  FREQ  CCP  RT  (VREG 0.7 V)
7
COS
6
5
4
3
2
SIN
1
0
270
135
180
90
225
Degrees of Deflection ()
45
315
0
Figure 1. Function Generator Output Voltage vs.
Degrees of Deflection
0
45
135
180
90
225
Frequency/Output Angle ()
270
315
Figure 2. Charge Pump Output Voltage vs.
Output Angle
7.0 V
1.50
1.25
(VSIN+) - (VSIN-)
1.00

Angle
-7.0 V
7.0 V
(VCOS+) - (VCOS-)
0.75
0.50
0.25
0.00
-0.25
-0.50
-0.75
-1.00
-1.25
 = ARCTAN
[
VSIN+ - VSINVCOS - VCOS-
-1.50
]
0
45
-7.0 V
Figure 3. Output Angle in Polar Form
135
180
90
Theoretical Angle ()
225
270
315
Figure 4. Nominal Output Deviation
45
40
35
30
25
20
Ideal Degrees
15
10
5
0
1
5
9
13
17
21
25
29
33
37
41
45
Nominall Angle (Degrees)
Figure 5. Nominal Angle vs. Ideal Angle (After Calibrating at 180)
December, 2012, Rev. 02
IL8190
Table 1. Function Generator Output Nominal Angle vs. Ideal Angle
(After Calibrating at 270)
Ideal
Degrees
NomiNomiNomiNomiNomiNomiIdeal
Ideal
Ideal
Ideal
Ideal
nal
nal
nal
nal
nal
nal
Degrees
Degrees
Degrees
Degrees
Degrees
Degrees
Degrees
Degrees
Degrees
Degrees
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.
December, 2012, Rev. 02
IL8190
CIRCUIT DESCRIPTION AND APPLICATION NOTES
The IL8190 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 6, 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 2.0 V and typical
hysteresis of 0.5 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, VOUT/F,
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:
VOUT/F = 2.0 V+2.0  FREQ  CCP  RT  (VREG - 0.7 V)
RT is a potentiometer used to adjust the gain of
the V/F output stage and give the correct meter
deflection. The V/F 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
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, , is equal to the V/F gain
multiplied by the function generator gain:
 = AV/F 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)
or,
 = 970  FREQ  CCP  RT
The ripple voltage at the V/F converter’s output
is determined by the ratio of CCP and C4 in the
formula:
CCP (VREG - 0.7 V)
V 
C4
VREG
2.0 V
VOUT/F
+
R3
V to F
0.25 V
Q3
VC(t)
+
SQOUT
FREQIN
+
CCP
R4
CP-
RT
CP+
C4
QSQUARE
Q1
Q2
2.0 V
Figure 6. Partial Schematic of Input and Charge Pump
December, 2012, Rev. 02
IL8190
T
tDCHG
tCHG
VCC
FREQIN
SQOUT
VREG
ICP+
VCP+
Figure 7. Timing Diagram of FREQIN and ICP
Ripple voltage on the V/F output causes
pointer or needle flutter especially at low input
frequencies.
The response time of the V/F is determined by
the time constant formed by RT and C4.
Increasing the value of C4 will reduce the ripple
on the V/F 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.
The IL8190 has an undervoltage detect circuit
that disables the input comparator when VCC falls
below 8.0 V (typical). With no input signal the V/F
output voltage decreases and the needle moves
towards zero. A second undervoltage detect
circuit at 6.0 V(typical) causes the function
generator to generate a differential SIN drive
voltage of zero volts and the differential COS
drive voltage to go as high as possible. This
combination of voltages (Figure 1) across the
meter coil moves the needle to the 0 position.
Connecting a large capacitor(> 2000 F) to the
VCC lead (C2 in Figure 8) increases the time
between these undervoltage points since the
capacitor discharges slowly and ensures that the
needle moves towards 0 as opposed to 360.
The exact value of the capacitor depends on the
response time of the system, he maximum meter
deflection and the current consumption of the
circuit. It should be selected by breadboarding the
design in the lab.
December, 2012, Rev. 02
IL8190
CCP
0.0033 F
30 PPM/C
3.0 k
Speedo Input
R4
1 CP+
1.0 k
C3
FREQIN
0.1 F
GND
GND
Battery
R1
3.9
D1
1.0 A 500 mW
600PV
GND
VOUT/F
SQOUT
R2
10 k
CP-
IL8190N
R3
C4
+
0.47F
Trim Resistor
RT
20 PPM/C
VREG
GND
GND
COS+
SIN+
COS-
SIN-
VCC
BIAS
C1
0.1F
C2
2000F
D2
50V,
500mW
Zener
COSINE
SINE
Air Core
Gauge
200
Speedometer
Notes:
1. C2 (> 2000 F) is needed if return to zero function is required.
2. The product of C4 and RT have a direct effect on gain and therefore directly affect temperature
compensation.
3. Ccp Range: 20 pF to 0.2 F.
4. R4 Range; 100 k to 500 k.
5. The IC must be protected from transients above 60 V and reverse battery conditions.
6. Additional filtering on the FREQIN lead may be required.
7. Gauge coil connections to the IC must be kept as short as possible (≤ 3.0 inch) for best pointer
stability.
Figure 8. Speedometer or Tachometer Application
December, 2012, Rev. 02
IL8190
DESIGN EXAMPLE
Maximum meter Deflection = 270
Maximum Input Frequency = 350 Hz
1. Select RT and CCP
 = 970  FREQ  CCP  RT = 270°
Let CCP = 0.0033 F, find RT
270
RT 
970  350Hz  0.0033 μF
RT = 243 k
RT should be a 250 k 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 k
The charge current for CCP is
VREG - 0.7 V
 1.90 mA
3.3 k
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.
1
T  10% 
 285 μs
350 Hz
Choose R4 = 1.0 k.
Discharge time:
tDCHG = R3  CCP = 3.3 k  0.0033 F = 10.9 s
Charge time:
tCHG = (R3 + R4)CCP = 4.3 k  0.0033 F = 14.2
s
the pointer always returns to the 0 position rather
than 360 under all operating conditions.
Figure 11 shows how the IL8190
and the
CS8441 are used to produce a Speedometer and
Odometer circuit.
In some cases a designer may wish to use the
IL8190 only as a driver for an air–core meter
having performed the V/F conversion elsewhere in
the circuit.
Figure 9 shows how to drive the IL8190 with a
DC voltage ranging from 2.0 V to 6.0 V. This is
accomplished by forcing a voltage on the VOUT/F
lead. The alternative scheme shown in Figure 10
uses an external op amp as a buffer and operates
over an input voltage range of 0 V to 4.0 V.
VREG
IL8190N
100 k
CP-
+
10 k
N/C
BIAS
VIN
2.0 V to 6.0 V DC
VOUT/F
Figure 9. Driving the IL8190 from an External
DC Voltage
Figures 9 and 10 are not temperature
compensated.
IL8190N
100 k
3. Determine C4
C4 is selected to satisfy both the maximum
allowable ripple voltage and response time of the
meter movement.
CCP (VREG  0.7V)
C4 
ΔVMAX
With C4 = 0.47 F, the V/F ripple voltage is 44
mV.
The last component to be selected is the return
to zero capacitor C2. This is selected by
increasing the input signal frequency to its
maximum so the pointer is at its maximum
deflection, then removing the power from the
circuit. C2 should be large enough to ensure that
VIN
100 k
+
10 k
0 V to 4.0 V DC
BIAS
+
CP-
VOUT/F
100 k
100 k
Figure 10. Driving the IL8190 from an External
DC Voltage Using an Op Amp Buffer
December, 2012, Rev. 02
IL8190N
Speedo
Input
CCP
0.0033 F
30 PPM/C
3.0 k
R4
1 CP+
1.0 k
C3
FREQIN
0.1 F
GND
GND
Battery
R1
3.9
D1
1.0 A 500 mW
600PV
VOUT/F
SQOUT
R2
10 k
CP+
0.47F
RT
Trim Resistor
20 PPM/C
243 k
GND
GND
COS+
SIN+
COS-
SIN-
VCC
BIAS
C1
0.1F
COSINE
GND
C4
VREG
IL8190N
R3
D2
50V,
500mW
Zener
SINE
Air Core
Gauge
200
Speedometer
C2
10F
1
CS8441
Air Core
Stepper
Motor
200
Odometer
Notes:
1. C2 = 10 F with CS8441 application.
2. The product of C4 and RT have a direct effect on gain and therefore directly affect temperature
compensation.
3. Ccp Range: 20 pF to 0.2 F.
4. R4 Range; 100 k to 500 k.
5. The IC must be protected from transients above 60 V and reverse battery conditions.
6. Additional filtering on the FREQIN lead may be required.
7. Gauge coil connections to the IC must be kept as short as possible (≤ 3.0 inch) for best pointer stability.
Figure 11. Speedometer With Odometer or Tachometer Application
12
December, 2012, Rev. 02
IL8190N
PACKAGE DIMENSIONS
13
December, 2012, Rev. 02