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

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FEATURES

• VERY FAST SLEW RATE — 900 V/µs

• POWER MOS TECHNOLOGY — 4A peak rating

• LOW INTERNAL LOSSES — 2V at 2A

• PROTECTED OUTPUT STAGE — Thermal Shutoff

• WIDE SUPPLY RANGE — ±15V TO ±40V

APPLICATIONS

• VIDEO DISTRIBUTION AND AMPLIFICATION

• HIGH SPEED DEFLECTION CIRCUITS

• POWER TRANSDUCERS UP TO 5 MHz

• MODULATION OF RF POWER STAGES

• POWER LED OR LASER DIODE EXCITATION

DESCRIPTION

The PA19 is a high voltage, high current operational ampli-

fier optimized to drive a variety of loads from DC through the

video frequency range. Excellent input accuracy is achieved

with a dual monolithic FET input transistor which is cascoded

by two high voltage transistors to provide outstanding common

mode characteristics. All internal current and voltage levels

are referenced to a zener diode biased on by a current source.

As a result, the PA19 exhibits superior DC and AC stability

over a wide supply and temperature range.

High speed and freedom from second breakdown is assured

by a complementary power MOS output stage. For optimum

linearity, especially at low levels, the power MOS transistors

are biased in a class A/B mode. Thermal shutoff provides

full protection against overheating and limits the heatsink

requirements to dissipate the internal power losses under

normal operating conditions. A built-in current limit of 0.5A

can be increased with the addition of two external resistors.

Transient inductive load kickback protection is provided by

two internal clamping diodes. External phase compensation

allows the user maximum flexibility in obtaining the optimum

slew rate and gain bandwidth product at all gain settings. A

heatsink of proper rating is recommended.

Thishybridcircuitutilizesthickfilm(cermet)resistors,ceramic

capacitors, and silicon semiconductor chips to maximize reli-

ability, minimize size, and give top performance. Ultrasonically

bonded aluminum wires provide reliable interconnections at all

operating temperatures. The 8-pin TO-3 package is hermeti-

cally sealed and electrically isolated. The use of compressible

thermal washers and/or improper mounting torque will void

the product warranty. Please see “General Operating Con-

siderations”.

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TYPICAL APPLICATION

This fast power driver utilizes the 900V/µs slew rate of the

PA19 and provides a unique interface with a current output

DAC. By using the DAC’s internal 1KΩ feedback resistor,

temperature drift errors are minimized, since the temperature

drift coefficients of the internal current source and the internal

feedback resistor of the DAC are closely matched. Gain of

V

with the external 500Ω and 110Ω form a “tee network” in the

feedback path around the PA19. This effective resistance

equals 6.5KΩ . Therefore the entire circuit can be modeled as

6.5KΩ feedback resistor from output to inverting input and a

5mA current source into the inverting input of the PA19. Now

we see the familiar current to voltage conversion for a DAC

where V

EQUIVALENT SCHEMATIC

EXTERNAL CONNECTIONS

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TYPICAL

APPLICATION

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8-PIN TO-3

PACKAGE STYLE CE