APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL prodlit@apexmicrotech.com

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FEATURES

• LOW COST

• WIDE COMMON MODE RANGE —

Includes negative supply

• WIDE SUPPLY VOLTAGE RANGE

Single supply: 5V to 40V

Split supplies: ±2.5V to ±20V

• HIGH EFFICIENCY — |Vs–2.2V| at 2.5A typ

• HIGH OUTPUT CURRENT — 3A

• LOW DISTORTION

APPLICATIONS

• HALF & FULL BRIDGE MOTOR DRIVERS

• AUDIO POWER AMPLIFIER

STEREO — 30W RMS per channel

BRIDGE — 60W RMS per package

• IDEAL FOR SINGLE SUPPLY SYSTEMS

5V — Peripherals, 12V — Automotive

28V — Avionic

DESCRIPTION

Theamplifierdesignconsistsofdualmonolithicinputandoutput

stages to achieve the desired input and output characteristics

of the PA74 and PA76. The input stage utilizes a dual power op

amp on a single chip monolithic that drives the output stages.

The output stages are configured in a non inverting unity gain

buffer configuration. The output stages of the amplifier are also

compensated for stability. The PA74 and PA76 dual amplifiers are

designed with both monolithic and hybrid technologies providing

a cost effective solution for applications requiring multiple ampli-

fiers per board or bridge mode configurations. Both amplifiers

are internally compensated but are not recommended for use

as unity gain followers.

This dual hybrid circuit utilizes a beryllia (BeO) substrate, thick

film resistors, ceramic capacitors and monolithic amplifiers to

maximize reliability and power handling capability, minimize size

and give top performance. Ultrasonically bonded aluminum wires

provide reliable interconnections at all operating temperatures.

The 8-Pin TO-3 package is hermetically sealed and electrically

isolated. The use of compressible isolation washers voids the

warranty.

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TYPICAL APPLICATION

R1 and R2 set up amplifier A in a non-inverting gain of 2.8.

Amp B is set up as a unity gain inverter driven from the output

of amp A. Note that amp B inverts signals about the reference

node, which is set at mid-supply (14V) by R5 and R6. When

the command input is 5V, the output of amp A is 14V. Since

this is equal to the reference node voltage, the output of amp

B is also 14V, resulting in 0V across the motor. Inputs more

positive than 5V result in motor current flow from left to right

(see Figure 1). Inputs less positive than 5V drive the motor in

the opposite direction.

The amplifiers are especially well-suited for this application.

The extended common mode range allows command inputs as

low as 0V. Its superior output swing abilities let it drive within

2V of supply at an output current of 2A. This means that a

command input that ranges from 0.714V to 9.286V will drive a

24V motor from full scale CCW to full scale CW at up to ±2A. A

single power op amp with an output swing capability of Vs –6

would require ±30V supplies and would be required to swing

48V p-p at twice the speed to deliver an equivalent drive.

EXTERNAL CONNECTIONS (TOP VIEWS)

PA74

PA76

FIGURE 1: BIDIRECTIONAL

SPEED CONTROL FROM A

SINGLE SUPPLY.

8-PIN TO-3

PACKAGE STYLE CE

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