XR-2207 Datasheet, PDF (11/24 Pages) Exar Corporation – Voltage-Controlled Oscillator

XR-2207
keying inputs (pins 8 and 9), as shown in the logic table
(Table 1). If a single timing resistor is activated, the
frequency is 1/RC. Otherwise, the frequency is either
1/(R₁||R₂)C or 1/(R₃||R₄)C.
Figure 13B shows a fixed frequency application using a
single timing resistor that is selected by grounding the
binary keying inputs. The oscillator frequency is 1/R₃C.
The squarewave output is obtained at pin 13 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 5kΩ) to the
positive supply. The triangle waveform obtained at pin 14
is centered about ground and has a peak amplitude of
V⁺/2.
Note
For Single-Supply Operation, Logic Levels are referenced to
voltage at Pin 10.
V_CC
CB ^VCC
C
12
3
Keying Inputs
V+
8A
9B
10 _GND
C1
C2
XR-2207
13
SWO
14
TWO
BIAS ¹¹
R 1 R 2 R 3 R 4 V-
4 5 6 7 12
R1 R2 R3 R4
V_EE
CB = Bypass Cap
CB
RL
Square Wave
Output
Triangle Wave
Output
V_EE
A. General Case
V_CC
CB ^VCC
C
12
3
V+
8A
9B
10 _GND
C1
C2
13
SWO
14
XR-2207 TWO
11
BIAS
R 1 R 2 R 3 R4 V-
4 5 6 7 12
R3
CB = Bypass Cap
V_EE
CB
RL
Square Wave
Output
Triangle Wave
Output
f=1/R3<C
V_EE
B. Fixed Frequency Case
Figure 13. Split-Supply Operation
Rev. 2.02
11