4

Function Generator Output (

∅=ArcTan

(Measured angle after calibration at 180°C)

For

(

(

(

B+

100

Ω

ZENER

5.4V

SINE

80mH

225

80mH

225

B+

15

18V

R2

2k

Ω

2k

Ω

1k

Ω

TACH INPUT

180k

Ω

*

1

µF

±10%

R1

1k

Ω

0.01

µF

* ADJUST FOR TRIMMING

CS289

Figure 1. Functional Diagram of CS289 Circuit.

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 ∅ =

through a Norton amplifier. The frequency applied at

Circuit Description

Charge Pump

Function Generator/Sine and Cosine Amplifiers

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

∅ is compared to

the divider network by the function generator circuitry.

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.