1
Features
SINE-
SINE+
Gnd
V
REG
F/V
OUT
SINE
Output
COS
Output
V
REG
7.0V
V
CC
COS-
COS+
Gnd
Gnd
FREQ
IN
SQ
OUT
CP+
Input
Comp.
+
+
Gnd
CP-
Voltage
Regulator
Function
Generator
+
+
High Voltage, Short
Circuit Protection
BIAS
Charge Pump
+
+
s
Direct Sensor Input
s
High Output Torque
s
Wide Output Voltage
Range
s
High Impedance Inputs
s
Accurate down to 10V V
CC
s
Fault Protection
Overvoltage
Short Circuit
s
Low Voltage Operation
Package Options
16 Lead PDIP
(internally fused leads)
CS8191
Precision Air-Core Tach/Speedo Driver
with Short Circuit Protection
1
CP+
2
3
4
5
6
7
8
SQ
OUT
FREQ
IN
Gnd
Gnd
COS+
COS-
V
CC
16
15
14
13
12
11
10
9
CP-
F/V
OUT
V
REG
Gnd
Gnd
SINE+
SINE-
BIAS
20 Lead SOIC
(internally fused leads)
1
CP+
2
3
4
5
6
7
8
SQ
OUT
FREQ
IN
NC
Gnd
Gnd
NC
COS+
16
15
14
13
12
11
10
CP-
F/V
OUT
V
REG
NC
Gnd
Gnd
NC
SIN+
9
COS-
SIN-
17
18
V
CC
BIAS
19
20
Description
Block Diagram
Absolute Maximum Ratings
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 con-
version, a bandgap reference for
stable operation and a function
generator with sine and cosine
amplifiers that differentially drive
the motor 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 (60V) fault conditions.
Enhanced circuitry permits func-
tional operation down to 8V.
CS8191
Supply Voltage
( 100ms pulse transient) ...........................................V
CC
= 60V
(continuous) ..................................................................V
CC
= 24V
Operating Temperature Range ........................................................-40C to +105C
Junction Temperature Range ...........................................................-40C to +150C
Storage Temperature Range.............................................................-55C to +165C
Electrostatic Discharge (Human Body Model) ...................................................4kV
Lead Temperature Soldering
Wave Solder (through hole styles only)..................10 sec. max, 260C peak
Reflow (SMD styles only)...................60 sec. max above 183C, 230C peak
Rev 3/9/99
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: info@cherry-semi.com
Web Site: www.cherry-semi.com
A Company
2
Electrical Characteristics: -40C T
A
105C, 8V V
CC
16V unless otherwise specified.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
CS8191
s Supply Voltage Section
I
CC
Supply Current
V
CC
= 16V, -40C, No Load
70
125
mA
V
CC
Normal Operation Range
8.0
13.1
16.0
V
s Input Comparator Section
Positive Input Threshold
2.4
2.7
3.0
V
Negative Input Threshold
2.0
2.3
V
Input Hysteresis
200
400
1000
mV
Input Bias Current *
0V V
IN
8V -2
10
A
Input Frequency Range
0
20
kHz
Input Voltage Range
in series with 1k
-1
V
CC
V
Output V
SAT
I
CC
= 10mA
0.15
0.40
V
Output Leakage
V
CC
= 7V
10
A
Logic 0 Input Voltage
2.0
V
*Note: Input is clamped by an internal 12V Zener.
s Voltage Regulator Section
Output Voltage
6.50
7.00
7.50
V
Output Load Current
10
mA
Output Load Regulation
0 to 10 mA
10
50
mV
Output Line Regulation
8.0V V
CC
16V
20
150
mV
Power Supply Rejection
V
CC
= 13.1V, 1V
P
/
P
1kHz
34
46
dB
s Charge Pump Section
Inverting Input Voltage
1.5
2.0
2.5
V
Input Bias Current
40
150
nA
V
BIAS
Input Voltage
1.5
2.0
2.5
V
Non Invert. Input Voltage
I
IN
= 1mA
0.7
1.1
V
Linearity*
@ 0, 87.5, 175, 262.5, + 350Hz
-0.10
0.28
+0.70
%
F/V
OUT
Gain
@ 350Hz, C
T
= 0.0033F, R
T
= 243k
7
10
13
mV/Hz
Norton Gain, Positive
I
IN
= 15A
0.9
1.0
1.1
I/I
Norton Gain, Negative
I
IN
= -15A
0.9
1.0
1.1
I/I
*Note: Applies to % of full scale (270).
s Function Generator Section: -40 T
A
85C, V
CC
= 13.1V unless otherwise noted.
Differential Drive Voltage
10V V
CC
16V
7.5
8.0
8.5
V
(V
COS
+ - V
COS
-)
Q = 0
Differential Drive Voltage
10V V
CC
16V
7.5
8.0
8.5
V
(V
SIN
+ - V
SIN
-)
Q = 90
Differential Drive Voltage
10V V
CC
16V
-8.5
-8.0
-7.5
V
(V
COS
+ - V
COS
-)
Q = 180
Differential Drive Voltage
10V V
CC
16V
-8.5
-8.0
-7.5
V
(V
SIN
+ - V
SIN
-)
Q = 270
Differential Drive Load
10V V
CC
16V, -40C
178
25C
239
105C
314
Zero Hertz Output Voltage
-0.08
0.0
+0.08
V
3
PACKAGE LEAD #
LEAD SYMBOL
FUNCTION
CS8191
Electrical Characteristics:
continued
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Package Lead Description
Typical Performance Characteristics
0
45
90
135
180
225
270
315
Output V
oltage (V)
Degrees of Deflection (
)
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
COS
SIN
0
45
90
135
180
225
270
315
F/V Output (V)
Frequency/Output Angle (
)
7
6
5
4
3
2
1
0
Figure 2: Charge Pump Output Voltage vs Output Angle
Figure 1: Function Generator Output Voltage
vs Degrees of Deflection
F/V
OUT
= 2.0V + 2 FREQ
C
T
R
T
(V
REG
- 0.7)
s Function Generator Section: continued
Function Generator Error *
Q = 0 to 225
-2
0
+2
deg
Reference Figures 1 - 4
Q = 226 to 305
-3
0
+3
deg
Function Generator Error
13.1V V
CC
16V
-1
0
+1
deg
Function Generator Error
13.1V V
CC
10V
-1
0
+1
deg
Function Generator Error
13.1V V
CC
8.0V
-7
0
+7
deg
Function Generator Error
25C T
A
80C
-2
0
+2
deg
Function Generator Error
25C T
A
105C
-4
0
+4
deg
Function Generator Error
40C T
A
25C
-2
0
+2
deg
Function Generator Gain
T
A
= 25C,
Q vs F/V
OUT
60
77
95
/V
*Note: Deviation from nominal per Table 1 after calibration at 0 and 270.
16L PDIP
20L SO
1
1
V
CC
Ignition or battery supply voltage.
2
2
V
REG
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
FREQ
IN
Speed or rpm input signal.
9
11
SQ
OUT
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/V
OUT
Output voltage proportional to input signal frequency.
4, 7, 14, 17
NC
No connection.
4
CS8191
Nominal Angle vs. Ideal Angle (After calibrating at 180)
+7V
7V
(V
COS+
) - (V
COS-
)
7V
Angle
-7V
Q
(V
SINE+
) - (V
SINE-
)
]
V
SIN+
V
SIN-
V
COS+
V
COS-
Q = ARCTAN
[
-1.50
Deviation (
)
0
45
90
135
180
225
270
315
-1.25
-1.00
-0.75
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
Theoretical Angle (
)
Figure 4: Nominal Output Deviation
Figure 3: Output Angle in Polar Form
Ideal Angle
(Degrees)
Nominal Angle (Degrees)
0
5
10
15
20
25
30
35
40
45
1
5
9
13
17
21
25
29
33
37
41
45
Ideal Degrees
Nominal Degrees
Typical Performance Characteristics: continued
0
0
1
1.09
2
2.19
3
3.29
4
4.38
5
5.47
6
6.56
7
7.64
8
8.72
9
9.78
10
10.84
11
11.90
12
12.94
13
13.97
14
14.99
15
16.00
16
17.00
17
17.98
18
18.96
19
19.92
20
20.86
21
21.79
22
22.71
23
23.61
24
24.50
25
25.37
26
26.23
27
27.07
28
27.79
29
28.73
30
29.56
31
30.39
32
31.24
33
32.12
34
33.04
35
34.00
36
35.00
37
36.04
38
37.11
39
38.21
40
39.32
41
40.45
42
41.59
43
42.73
44
43.88
45
45.00
50
50.68
55
56.00
60
60.44
65
64.63
70
69.14
75
74.00
80
79.16
85
84.53
90
90.00
95
95.47
100
100.84
105
106.00
110
110.86
115
115.37
120
119.56
125
124.00
130
129.32
135
135.00
140
140.68
145
146.00
150
150.44
155
154.63
160
159.14
165
164.00
170
169.16
175
174.33
180
180.00
185
185.47
190
190.84
195
196.00
200
200.86
205
205.37
210
209.56
215
214.00
220
219.32
225
225.00
230
230.58
235
236.00
240
240.44
245
244.63
250
249.14
255
254.00
260
259.16
265
264.53
270
270.00
275
275.47
280
280.84
285
286.00
290
290.86
295
295.37
300
299.21
305
303.02
Ideal
Q
Nominal
Ideal
Q
Nominal
Ideal
Q
Nominal
Ideal
Q
Nominal
Ideal
Q
Nominal
Ideal
Q
Nominal
Degrees
Q Degrees
Degrees
Q Degrees
Degrees
Q Degrees
Degrees
Q Degrees
Degrees
Q Degrees
Degrees
Q Degrees
Table 1:
Function Generator Output Nominal Angle vs. Ideal Angle (After calibrating at 270)
Note:
Temperature, voltage and nonlinearity not included.
Note:
Temperature, voltage and nonlinearity not included.
5
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 conver-
sion, a bandgap voltage regulator for stable operation,
and a function generator with sine and cosine amplifiers
to differentially drive the motor coils.
From the simplified block diagram of Figure 5A, the
input signal is applied to the FREQ
IN
lead, this is the
input to a high impedance comparator with a typical pos-
itive input threshold of 2.7V and typical hysteresis of
0.4V. The output of the comparator, SQ
OUT
, is applied to
the charge pump input CP+ through an external capacitor
C
T
. When the input signal changes state, C
T
is charged
or discharged through R3 and R4. The charge accumulat-
ed on C
T
is mirrored to C4 by the Norton Amplifier cir-
cuit comprising of Q1, Q2 and Q3. The charge pump out-
put voltage, F/V
OUT
, ranges from 2V to 6.3V depending
on the input signal frequency and the gain of the charge
pump according to the formula:
F/V
OUT
= 2.0V + 2
FREQ C
T
R
T
(V
REG
0.7V)
R
T
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 on-chip amplifier and function genera-
tor 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,
Q, is equal to the F/V gain multiplied
by the function generator gain:
Q = A
F/V
A
FG
,
where:
A
FG
= 77/V (typ)
The relationship between input frequency and output
angle is:
Q = A
FG
2 FREQ C
T
R
T
(V
REG
0.7V)
or,
Q = 970 FREQ C
T
R
T
The ripple voltage at the F/V converters output is deter-
mined by the ratio of C
T
and C4 in the formula:
V =
Ripple voltage on the F/V output causes pointer or nee-
dle flutter especially at low input frequencies.
The response time of the F/V is determined by the time
constant formed by R
T
and C4. Increasing the value of C4
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 unac-
ceptable for many applications.
Design Example
Maximum meter Deflection = 270
Maximum Input Frequency = 350Hz
1. Select R
T
and C
T
Q = A
GEN
F/V
F/V
= 2
FREQ C
T
R
T
(V
REG
0.7V)
Q = 970 FREQ C
T
R
T
Let C
T
= 0.0033F, Find R
T
R
T
=
R
T
= 243k
R
T
should be a 250k potentiometer to trim out any inac-
curacies due to IC tolerances or meter movement pointer
placement.
2. Select R3 and R4
Resistor R3 sets the output current from the voltage regu-
lator. The maximum output current from the voltage reg-
ulator is 10mA, R3 must ensure that the current does not
exceed this limit.
Choose R3 = 3.3k
The charge current for C
T
is:
= 1.90mA
C1 must charge and discharge fully during each cycle of
the input signal. Time for one cycle at maximum frequen-
cy is 2.85ms. To ensure that C
T
is discharged, assume that
the (R3 + R4) C
T
time constant is less than 10% of the
minimum input frequency pulse width.
T = 285s
Choose R4 = 1k.
Charge time:
T = R3
C
T
= 3.3k
0.0033F = 10.9s
Discharge time:T = (R3 + R4)C
T
= 4.3k
0.0033F = 14.2s
3. Determine C4
C4 is selected to satisfy both the maximum allowable rip-
ple voltage and response time of the meter movement.
C4 =
With C4 = 0.47F, the F/V ripple voltage is 44mV.
Figure 7 shows how the CS8191 and the CS8441 are used
to produce a Speedometer and Odometer circuit.
C
T
(V
REG
0.7V)
V
RIPPLE(MAX)
V
REG
0.7V
3.3k
270
970
350Hz 0.0033F
C
T
(V
REG
0.7V)
C4
Circuit Description and Application Notes
CS8191
+
R
T
C4
CP
+
F/V
OUT
F to V
2.5V
Q2
Q1
Q3
0.25V
CP+
R4
C
T
V
C
(t)
+
R3
V
REG
SQ
OUT
Q
SQUARE
2.7V
FREQ
IN
T
PW
T-PW
FREQ
IN
I
CP+
SQ
OUT
V
CC
V
REG
0
0
0
V
CP+
Figure 5A: Partial Schematic of Input and Charge Pump
Figure 5B: Timing Diagram of FREQ
IN
and I
C
P
6
CS8191
Circuit Description and Application Notes: continued
7
CS8191
Speedometer/Odometer or Tachometer Application
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 8 shows how to drive the CS8191 with a DC voltage
ranging from 2V to 6V. This is accomplished by forcing a
voltage on the F/V
OUT
lead. The alternative scheme shown
in figure 9 uses an external op amp as a buffer and operates
over an input voltage range of 0V to 4V.
Figure 8. Driving the CS8191 from an external DC voltage.
An alternative solution is to use the CS4101 which has a
separate function generator input lead and can be driven
directly from a DC source. Figure 8 and 9 are not tempera-
ture compensated.
Figure 9. Driving the CS8191 from an external DC voltage using an Op
Amp Buffer.
V
IN
0V to 4V DC
F/V
OUT
CP-
CS8191
BIAS
100k
W
100k
W
+
-
+
-
10k
W
100k
W
100k
W
F/V
OUT
CP-
CS8191
BIAS
10k
W
100k
W
V
REG
+
-
N/C
V
IN
2V to 6V DC
Figure 6
R1 - 3.9, 500mW
R2 - 10k
R3 - 3k
R4 - 1k
R
T
- Trim Resistor +/- 20 PPM/DEG. C
C1 - 0.1F
C2 - With CS-8441 application, 10F
C3 - 0.1F
C4 - 0.47F
C
T
- 0.0033F, +/- 30 PPM/C
D1 - 1A, 600 PIV
D2 - 50V, 500mW Zener
Note 1: The product of C
T
and R
T
have a direct effect on gain and
therefore directly effect temperature compensation.
Note 2: C4 Range; 20pF to .2F.
Note 3: R4 Range; 100k to 500k.
Figure 7
Note 4: The IC must be protected from transients above 60V and reverse
battery conditions.
Note 5: Additional filtering on the FREQ
IN
lead may be required.
1
CS8441
C2
Air Core
Stepper Motor
200
W
Odometer
1
CP+
2
3
4
5
6
7
8
SQ
OUT
FREQ
IN
Gnd
Gnd
COS+
COS-
16
15
14
13
12
11
10
9
CP-
F/V
OUT
V
REG
Gnd
Gnd
SINE+
SINE-
BIAS
CS8191
D1
+
C4
R
T
COSINE
SINE
Battery
V
CC
CP+
R1
D2
C1
R4
Typical Speedometer
Input
Ground
C
T
R3
R2
C3
Air Core
Gauge
Speedometer
1
CP+
2
3
4
5
6
7
8
SQ
OUT
FREQ
IN
Gnd
Gnd
COS+
COS-
16
15
14
13
12
11
10
9
CP-
F/V
OUT
V
REG
Gnd
Gnd
SINE+
SINE-
BIAS
CS8191
D1
+
C4
R
T
COSINE
SINE
Air Core
Gauge
Speedometer
Battery
V
CC
CP+
R1
D2
C1
R4
Typical Speedometer
Input
Ground
C
T
R3
R2
C3
D
Lead Count
Metric
English
Max
Min
Max
Min
16L PDIP
(internally fused leads)
19.69 18.67
.775
.735
20L SOIC
(internally fused leads)
13.00 12.60
.512
.496
8
Rev. 3/9/99
CS8191
Thermal Data
16L PDIP*
20L SOIC*
R
QJC
typ
15
9
C/W
R
QJA
typ
50
55
C/W
Package Specification
PACKAGE DIMENSIONS IN mm (INCHES)
PACKAGE THERMAL DATA
Part Number
Description
CS8191XNF16
16L PDIP (internally fused leads)
CS8191XDWF20
20L SOIC (internally fused leads)
CS8191XDWFR20 20L SOIC (internally fused leads)
(tape & reel)
Ordering Information
1999 Cherry Semiconductor Corporation
Cherry Semiconductor Corporation reserves the
right to make changes to the specifications without
notice. Please contact Cherry Semiconductor
Corporation for the latest available information.
Plastic DIP (N); 300 mil wide
0.39 (.015)
MIN.
2.54 (.100) BSC
1.77 (.070)
1.14 (.045)
D
Some 8 and 16 lead
packages may have
1/2 lead at the end
of the package.
All specs are the same.
.203 (.008)
.356 (.014)
REF: JEDEC MS-001
3.68 (.145)
2.92 (.115)
8.26 (.325)
7.62 (.300)
7.11 (.280)
6.10 (.240)
.356 (.014)
.558 (.022)
1.27 (.050) BSC
7.60 (.299)
7.40 (.291)
10.65 (.419)
10.00 (.394)
D
0.32 (.013)
0.23 (.009)
1.27 (.050)
0.40 (.016)
REF: JEDEC MS-013
2.49 (.098)
2.24 (.088)
0.51 (.020)
0.33 (.013)
2.65 (.104)
2.35 (.093)
0.30 (.012)
0.10 (.004)
Surface Mount Wide Body (DW); 300 mil wide
*Internally Fused Leads
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