Datasheet MAX038 (Analog Devices) - 8

ManufacturerAnalog Devices
DescriptionHigh-Frequency Waveform Generator
Pages / Page17 / 8 — High-Frequency Waveform Generator. Detailed Description
File Format / SizePDF / 491 Kb
Document LanguageEnglish

High-Frequency Waveform Generator. Detailed Description

High-Frequency Waveform Generator Detailed Description

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MAX038
High-Frequency Waveform Generator
3 4 A0 A1 5 COSC TRIANGLE SINE SINE OSCILLATOR OSC A C SHAPER F 6 GND OSC B OUT 19 TRIANGLE MUX SQUARE 8 FADJ RL CL OSCILLATOR CURRENT COMPARATOR 7 DADJ GENERATOR 10 IIN MAX038 RF RD RIN -250μA SYNC 14 COMPARATOR 1 REF 2.5V VOLTAGE REFERENCE * 17 V+ PDO 12 +5V PHASE 20 V- -5V DETECTOR PDI 13 2, 9, 11, 18 GND DGND DV+ 15 16 * = SIGNAL DIRECTION, NOT POLARITY +5V = BYPASS CAPACITORS ARE 1μF CERAMIC OR 1μF ELECTROLYTIC IN PARALLEL WITH 1nF CERAMIC. * Figure 1. Block Diagram and Basic Operating Circuit
Detailed Description
with constant currents, simultaneously producing a tri- angle wave and a square wave (Figure 1). The charg- The MAX038 is a high-frequency function generator ing and discharging currents are controlled by the cur- that produces low-distortion sine, triangle, sawtooth, or rent flowing into IIN, and are modulated by the voltages square (pulse) waveforms at frequencies from less than applied to FADJ and DADJ. The current into IIN can be 1Hz to 20MHz or more, using a minimum of external varied from 2µA to 750µA, producing more than two components. Frequency and duty cycle can be inde- decades of frequency for any value of C pendently controlled by programming the current, volt- F. Applying ±2.4V to FADJ changes the nominal frequency (with age, or resistance. The desired output waveform is V selected under logic control by setting the appropriate FADJ = 0V) by ±70%; this procedure can be used for fine control. code at the A0 and A1 inputs. A SYNC output and phase detector are included to simplify designs requir- Duty cycle (the percentage of time that the output wave- ing tracking to an external signal source. form is positive) can be controlled from 10% to 90% by applying ±2.3V to DADJ. This voltage changes the C The MAX038 operates with ±5V ±5% power supplies. F charging and discharging current ratio while maintain- The basic oscillator is a relaxation type that operates by ing nearly constant frequency. alternately charging and discharging a capacitor, CF, 8 Maxim Integrated Document Outline Blank Page