XR-2206 Datasheet, PDF (10/16 Pages) Exar Corporation – Monolithic Function Generator

XR-2206
V_CC
1mF
4
1
5
16
Mult.
C
VCO
And
15
6
Sine
14
Shaper
9
13
R_{1 7 Current}
R_{2 8} Switches
+1
2
11
ƪ ƫ f
+
2
C
1
R₁ ) R₂
Duty Cycle =
R₁
R₁ ) R₂
Sawtooth Output
Pulse Output
10 12
+
1mF
3
R₃
24K
XR-2206
5.1K
+
V_CC
10mF
V_CC
5.1K
5.1K
Figure 14. Circuit for Pulse and Ramp Generation.
Frequency-Shift Keying
APPLICATIONS INFORMATION
The XR-2206 can be operated with two separate timing
resistors, R₁ and R₂, connected to the timing Pin 7 and 8,
respectively, as shown in Figure 13. Depending on the
polarity of the logic signal at Pin 9, either one or the other
of these timing resistors is activated. If Pin 9 is
open-circuited or connected to a bias voltage  2V, only
R₁ is activated. Similarly, if the voltage level at Pin 9 is
1V, only R₂ is activated. Thus, the output frequency can
be keyed between two levels. f₁ and f₂, as:
f₁ = 1/R₁C and f₂ = 1/R₂C
For split-supply operation, the keying voltage at Pin 9 is
referenced to V^-.
Output DC Level Control
Sine Wave Generation
Without External Adjustment
Figure 11 shows the circuit connection for generating a
sinusoidal output from the XR-2206. The potentiometer,
R₁ at Pin 7, provides the desired frequency tuning. The
maximum output swing is greater than V⁺/2, and the
typical distortion (THD) is < 2.5%. If lower sine wave
distortion is desired, additional adjustments can be
provided as described in the following section.
The circuit of Figure 11 can be converted to split-supply
operation, simply by replacing all ground connections
with V^-. For split-supply operation, R₃ can be directly
connected to ground.
The dc level at the output (Pin 2) is approximately the
same as the dc bias at Pin 3. In Figure 11, Figure 12 and
Figure 13, Pin 3 is biased midway between V+ and
ground, to give an output dc level of  V⁺/2.
Rev. 1.03
10