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CA5420A

0.5MHz, Low Supply Voltage, Low Input

Current BiMOS Operational Amplifiers

The CA5420A is an integrated circuit operational amplifier that

combines PMOS transistors and bipolar transistors on a single

monolithic chip. It is designed and guaranteed to operate in

microprocessor logic systems that use V+ = 5V, V- = GND,

since it can operate down to

±1V supplies. It will also be

suitable for 3.3V logic systems.

The CA5420A BiMOS operational amplifier features gate-

protected PMOS transistors in the input circuit to provide very

high input impedance, very low input currents (less than 1pA).

The internal bootstrapping network features a unique

guardbanding technique for reducing the doubling of leakage

current for every +10°C increase in temperature. The CA5420A

operates at total supply voltages from 2V to 20V either single or

dual supply. This operational amplifier is internally phase

compensated to achieve stable operation in the unity gain

follower configuration. Additionally, it has access terminals for a

supplementary external capacitor if additional frequency roll-off

is desired. Terminals are also provided for use in applications

requiring input offset voltage nulling. The use of PMOS in the

input stage results in common-mode input voltage capability

down to 0.45V below the negative supply terminal, an important

attribute for single supply application. The output stage uses a

feedback OTA type amplifier that can swing essentially from

rail-to-rail. The output driving current of 1.0mA (Min) is provided

by using nonlinear current mirrors.

This device has guaranteed specifications for 5V operation

over the full military temperature range of -55°C to +125°C.

The CA5420A has the same 8 lead pinout used for the

industry standard 741.

Features

• CA5420A at 5V Supply Voltage with Full Military

Temperature Range Guaranteed Specifications

• CA5420A Guaranteed to Operate from

±1V to ±10V

Supplies

• 2V Supply at 300µA Supply Current

• 1pA (Typ) Input Current (Essentially Constant to +85°C)

• Rail-to-Rail Output Swing (Drive

±2mA Into 1kΩ Load)

• Pin Compatible with 741 Op Amp

• Pb-Free Available (RoHS Compliant)

Applications

• pH Probe Amplifiers

• Picoammeters

• Electrometer (High Z) Instruments

• Portable Equipment

• Inaccessible Field Equipment

• Battery Dependent Equipment (Medical and Military)

• 5V Logic Systems

• Microprocessor Interface

Functional Diagram

MOS

BIPOLAR

X1

X1

MOS

BIPOLAR

OTA BUFFER

(X2)

HIGH GAIN

(50k)

BUFFER AMPS;

BOOTSTRAPPED

INPUT PROTECTION

NETWORK

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+

Data Sheet

December 8, 2009

FN1925.6

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

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