XR8038 Datasheet, PDF (6/16 Pages) Exar Corporation – Precision Waveform Generator

XR-8038A
SYSTEM DESCRIPTION
The XR-8038A precision waveform generator produces
highly stable and sweepable square, triangle, and sine
waves across eight frequency decades. The device time
base employs resistors and a capacitor for frequency and
duty cycle determination. The generator contains dual
comparators, a flip-flop driving a switch, current sources,
buffers, and a sine wave convertor. Three identical
frequency outputs are simultaneously available. Supply
voltage can range from 10V to 30V, or ±5V to ±15V with
dual supplies.
Unadjusted sine wave distortion is typically less than
0.7% with the sine wave distortion adjust pin (Pin 1) open.
Distortion levels may be improved by including a 100kΩ
potentiometer between the supplies, with the wiper
connected to Pin 1.
Small frequency deviation (FM) is accomplished by
applying modulation voltage to Pins 7 and 8; large
frequency deviation (sweeping) is accomplished by
applying voltage to Pin 8 only. Sweep range is typically
1000:1.
The square wave output is an open collector transistor;
output amplitude swing closely approaches the supply
voltage. Triangle output amplitude is typically 1/3 of the
supply, and sine wave output reaches 0.22 of the supply
voltage.
+15V
R_A
R_B
C1
S1
4
5
DCA1 DCA2
10
TC
Timing
Circuitry
7 _FMBI
U1
8 _FMSI
V_EE
11
1
12
6
SA1 SA2
Sine
Converter
V_CC
2
SWO
3
TWO
R_L
Sine Wave
Triangle Wave
Square Wave
Converter
9
SQO
Square Wave
XR-8038A
–15V
Figure 2. Generalized Test Circuit
Rev. 2.01
6