GENERAL DESCRIPTION

The ALD4704A/ALD4704B/ALD4704 is a dual monolithic operational

amplifier with MOSFET input that has rail-to-rail input and output voltage

ranges. The input voltage range and output voltage range are very close

to the positive and negative power supply voltages. Typically the input

voltage can be beyond positive power supply voltage V+ or the negative

power supply voltage V- by up to 300mV. The output voltage swings to

within 60mV of either positive or negative power supply voltages at rated

load.

With high impedance load, the output voltage of the ALD4704A/

ALD4704B/ALD4704 approaches within 1mV of the power supply rails.

This device is designed as an alternative to the popular J-FET input

operational amplifier in applications where lower operating voltages,

such as 9V battery or ±3.25V to ±5V power supplies are being used. The

ALD4704A/ALD4704B/ALD4704 offers high slew rate of 5V/μs. It is

designed and manufactured with Advanced Linear Devices' standard

enhanced ACMOS silicon gate CMOS process, and it offers low unit

cost and exceptional reliability.

The rail-to-rail input and output feature of the ALD4704A/ALD4704B/

ALD4704 expands signal voltage range for a given operating supply

voltage and allows numerous analog serial stages to be implemented

without losing operating voltage margin. The output stage is designed

to drive up to 10mA into 400pF capacitive and 1.5KΩ resistive loads at

unity gain and up to 4000pF at a gain of 5. Short circuit protection to either

ground or the power supply rails is at approximately 15mA clamp

current. Due to complementary output stage design, the output can

source and sink 10mA into a load with symmetrical drive and is ideally

suited for applications where push-pull voltage drive is desired.

For each of the operational amplifier, the offset voltage is trimmed onchip

to eliminate the need for external nulling in many applications. For

precision applications, the output is designed to settle to 0.1 in 2μs. In

large signal buffer applications, the operational amplifier can function as

an ultrahigh input impedance voltage follower /buffer that allows input

and output voltage swings from positive to negative supply voltages.

This feature is intended to greatly simplify systems design and eliminate

higher voltage power supplies in many applications. Additionally, robust

design and rigorous screening make this device especially suitable for

operation in temperature-extreme environments and rugged conditions.

APPLICATIONS

• Voltage amplifier

• Voltage follower/buffer

• Charge integrator

• Photodiode amplifier

• Data acquisition systems

• High performance portable

instruments

• Signal conditioning circuits

• Low leakage amplifiers

• Active filters

• Sample/Hold amplifier

• Picoammeter

• Current to voltage converter

• Coaxial cable driver

• Capacitive sensor amplifier

• Piezoelectric transducer amplifier

FEATURES

• Rail-to-rail input and output voltage ranges

• 5.0V/μs slew rate

• Symmetrical push-pull output drive

• Inputs can extend beyond supply rails by 300mV

• Outputs settle to 2mV of supply rails

• High capacitive load capability -- up to 4000pF

• No frequency compensation required -- unity

gain stable

• Extremely low input bias currents -- 1.0pA

typical (20pA max.)

• Ideal for high source impedance applications

• High voltage gain -- 100V/mV typical

• Output short circuit protected

• Unity gain bandwidth of 2.1MHz

• Suitable for rugged, temperature-extreme

environments