cs289gdwr20 ON Semiconductor, cs289gdwr20 Datasheet - Page 4

• Manufacturer Part Number: cs289gdwr20
• Description: 20ma Air-core Tachometer Drive Circuit
• Manufacturer: ON Semiconductor

The input frequency is buffered through a transistor, then
applied to the charge pump for frequency-to-voltage con-
version (Figure 1). The charge pump output voltage, E ,
will range from 2.1V with no input ( = 0°) to 7.1V at
270°. The charge that appears on C
through a Norton amplifier. The frequency applied at
S
reflects the charge as a voltage across resistor R
Figure 1. Functional Diagram of CS289 Circuit.
Q
Function Generator Output ( ): V
For
(
Temperature Sensitivity: V
(
Voltage Sensitivity: T
(
IN charges and discharges C
=ArcTan
A
MT
MV
-
MT
MV
A
=
=
M
) 3.5°C, -20°C T +85°C
) 2°, 11.3V V
=45°, 90°, 135°, 180°, 225°, 270°, (Desired angle)
) 4.0°
M
M
(T=25°C) - M (-20°C T +85°C)
(V
V
V
sine
CC
cos
=13.1V) -
(Measured angle after calibration at 180°C)
CC
Charge Pump
A
=25°C
15V
CC
M
T
=13.1V
(11.3V V
through R
T
CC
is reflected to C
=13.1V, T
CC
1
and R
15V)
T
A
.
=25°C
2
Circuit Description
. C
OUT
ZENER
5.4V
OUT
100
=
B+
4
The output waveforms of the sine and cosine amplifiers
are derived by On-Chip Amplifier/Comparator circuitry.
The various trip points for the circuit (i.e. 90°, 180°, 270°)
are determined by an internal resistor divider connected
to the voltage regulator. The voltage E
the divider network by the function generator circuitry.
Use of an external zener reference at V
and cosine amplifiers to swing positive and negative with
respect to this reference. The output magnitudes and
directions have the relationship as shown in Typical
Characteristics diagrams.
Note: Pin connections referenced are for the 14L DIP.
B+
80mH
225
SINE
80mH
225
Function Generator/Sine and Cosine Amplifiers
15
18V
CS289
R2
2k
* ADJUST FOR TRIMMING
1k
2k
1k
R1
E
TACH INPUT
Z
C
allows both sine
10%
1 F
is compared to
OUT
0.01 F
C
T
R
180k
*
T