XR-8038A

Precision Waveform Generator

GENERAL DESCRIPTION

The XR-8038A is a precision waveform generator IC

capable of producing sine, square, triangular, sawtooth,

and pulse waveforms, with a minimum number of exter-

nal components and adjustments. The 8038A allows the

elimination of the external distortion adjusting resistor

which greatly improves the temperature drift of distortion,

as well as lowering external parts count. Its operating

frequency can be selected over eight decades of fre-

quency, from 0.001Hz to 200KHz, by the choice of external

R-C components. The frequency of oscillation is highly

stable over a wide range of temperature and supply volt-

age changes. Both full frequency sweeping as well as

smaller frequency variations (FM) can be accomplished

with an external control voltage. Each of the three basic

waveform outputs, (i.e., sine, triangle and square) are simul-

taneously available from independent output terminals.

The XR-8038A monolithic waveform generator uses

advanced processing technology and Schottky-barrier

diodes to enhance its frequency performance. It can be

readily interfaced with a monolithic phase-detector circuit,

such as the XR-2228 to form stable phase-locked circuits.

FEATURES

Low Frequency Drift

50ppm/°C, Typical

Simultaneous Sine, Triangle, and Square Wave Outputs

Low Sine Wave Distortion — THD –

~ 1%

High FM and Triangle Linearity

Wide Frequency Range

0.001Hz to 200KHz

Variable Duty Cycle

2% to 98%

Low Distortion Variation with Temperature

APPLICATIONS

Precision Waveform Generation

Sweep and FM Generation

Tone Generation

Instrumentation and Test Equipment Design

Precision PLL Design

ABSOLUTE MAXIMUM RATINGS

Power Supply

36V

Power Dissipation (package limitation)

Ceramic Package

750mW

Derate Above +25°C

6.0mW/°C

Plastic Package

625mW

Derate Above +25°C

5mW/°C

Storage Temperature Range

–65°C to +150°C

PIN ASSIGNMENT

ORDERING INFORMATION

Part Number

Package

Operating Temperature

XR-8038AM

Ceramic

–55°C to +125°C

XR-8038AN

Ceramic

0°C to +70°C

XR-8038AP

Plastic

0°C to +70°C

XR-8038ACN

Ceramic

0°C to +70°C

XR-8038ACP

Plastic

0°C to +70°C

SYSTEM DESCRIPTION

The XR-8038A precision waveform generator produces

highly stable and sweepable square, triangle, and sine

waves across eight frequency decades. The XR-8038A

is an advanced version of the XR-8038, with improved

sine distortion temperature drift. The device time base em-

ploys 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 100k

Ω

potentiometer between the supplies, with the wiper con-

nected to Pin 1.

Small frequency deviation (FM) is accomplished by ap-

plying modulation voltage to Pins 7 and 8; large frequency

deviation (sweeping) is accomplished by applying volt-

age 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 volt-

age. Triangle output amplitude is typically 1/3 of the

supply, and sine wave output reaches 0.22 of the supply

voltage.

1

2

3

4

11

10

9

8

XR-8038A

SINE ADJ

DUTY CYCLE

ADJ

NC

SINE ADJ

TIMING

CAPACITOR

5

6

7

12

13

14

FM BIAS

NC

–V OR GND

FM SWEEP

INPUT

~

May 1994-4