XR-2209 Datasheet, PDF (10/20 Pages) Exar Corporation – Voltage-Controlled Oscillator

XR-2209
MODES OF OPERATION
Split Supply Operation
Figure 12 is the recommended configuration for split
supply operation. Diode D₁ in the figure assures that the
triangle output swing at pin 8 is symmetrical about
ground. The circuit operates with supply voltages ranging
from $4V to $13V. Minimum drift occurs with $6V
supplies. For operation with unequal supply voltages, see
Figure 5.
With the generalized circuit of Figure 12, the frequency of
operation is determined by the timing capacitor, C, and
the timing resistor.
The squarewave output is obtained at pin 7 and has a
peak-to-peak voltage swing equal to the supply voltages.
This output is an “open-collector” type and requires an
external pull-up load resistor (nominally 5kW) to the
positive supply. The triangle waveform obtained at pin 8 is
centered about ground and has a peak amplitude of
V_CC/2.
V_CC
V_CC
C
1mF
R_L
12
V_CC C1
3
C2 _SWO ⁷
XR-2209
TWO ⁸
BIAS ⁵
Square Wave
Output
Triangle Wave
Output
TR
V_EE
D1
4
6
10K
1mF
V_EE
R
1mF
V_EE
Figure 12. Split-Supply Operation, Recommended Configuration
Rev. 2.02
10