Circuit Description
Function Generator/Sine and Cosine Amplifiers
Charge Pump
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 EÆ is compared to
the divider network by the function generator circuitry.
Use of an external zener reference at VZ allows both sine
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.
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, EÆ,
will range from 2.1V with no input (Æ= 0¡) to 7.1V at Æ =
270¡. The charge that appears on CT is reflected to COUT
through a Norton amplifier. The frequency applied at
SQIN charges and discharges CT through R1 and R2. COUT
reflects the charge as a voltage across resistor RT.
Note: Pin connections referenced are for the 14L DIP.
Function Generator Output (Æ): VCC=13.1V, TA=25¡C
Vsine
Vcos
Æ=ArcTan
(Measured angle after calibration at 180¡C)
1kW
TACH INPUT
For ÆA=45¡, 90¡, 135¡, 180¡, 225¡, 270¡, (Desired angle)
(ÆA-ÆM)²4.0¡
2kW
15
B+
18V
R2
2kW
EQ
Temperature Sensitivity: VCC=13.1V
ÆÆMT=ÆM (T=25¡C) -ÆM (-20¡C²T²+85¡C)
(ÆÆMT)²3.5¡C, -20¡C²T²+85¡C
COUT
RT
1mF
180kW
Voltage Sensitivity: TA=25¡C
±10%
CS289
*
ÆÆMV=ÆM (VCC=13.1V) -ÆM (11.3V²VCC²15V)
(ÆÆMV)²2¡, 11.3V²VCC²15V
B+
100W
80mH
225
R1
CT
ZENER
5.4V
SINE
80mH
225
1kW
0.01mF
* ADJUST FOR TRIMMING
Figure 1. Functional Diagram of CS289 Circuit.
4
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
