PAD04 – Rev A
KEY FEATURES
- LOW COST
- SMALL SIZE – 30mm SQUARE
- HIGH VOLTAGE – 200 VOLTS
- HIGH OUTPUT CURRENT – 10A PEAK
- 30 WATT DISSIPATION CAPABILITY
- 200V/µS SLEW RATE
- RoHS COMPLIANT
APPLICATIONS
- INDUSTRIAL INK JET PRINT HEADS
- HIGH VOLTAGE INSTRUMENTATION
- PIEZO TRANSDUCER DRIVE
- LCD PANEL TESTING
DESCRIPTION
The PAD04 compact high voltage op amp is constructed with surface mount components to provide a cost-effective solution for many industrial applications such as an ink jet print head driver. With a footprint only 30mm square the PAD04 offers outstanding performance that rivals more expensive hybrid components. An integrated heat sink and fan cooling are included. User selectable external compensation tailors the amplifier’s response to the application requirements. The PAD04 is capable of driving 150V pulses into 47nF at 50 kHz with a duty cycle of 40% and a slew rate of 200V/µS (see application note AN-46). The PAD04 is built on a thermally conductive but electrically insulating substrate. No BeO is used in the PAD04. For custom applications the PAD04-1 version of the amplifier is available without the integrated heat sink and fan capable of higher power dissipation with a properly rated heat sink.
A NEW CONCEPT
A critical task in any power amplifier application is cooling the amplifier. Until now component amplifier manufacturers often treated this task as an after-thought, left for the user to figure out. At Power Amp Design the best heat sink and fan is chosen at the start and becomes an integral part of the overall amplifier design. The result is the most compact and volumetric efficient design combination at the lowest cost. In addition, this integrated solution concept offers an achievable real-world power dissipation rating, not the ideal rating usually cited when the amplifier case is somehow kept at 25oC. The user no longer needs to specify, procure or assemble separate components.
CIRCUIT & CONNECTIONS
EQUIVALENT CIRCUIT
PINOUT & CONNECTIONS
ABSOLUTE MAXIMUM RATINGS
OPERATING CONSIDERATIONS
SAFETY FIRST
The operating voltages of the PAD04 are potentially deadly. When developing an application circuit, it is wise to begin with power supply voltages as low as possible while checking for circuit functionality. Increase supply voltages slowly as confidence in the application circuit increases. Always use a “hands-off” method whereby test equipment probes are attached only when power is off.
COOLING FAN
The PAD04 relies on its fan for proper cooling of the amplifier. Make sure that air flow from the fan and to the heat sink remains unobstructed. Air is drawn into the heat sink fin area and exhausted via the fan out of the top of the amplifier assembly. To eliminate electrical noise created by the cooling fan we recommend a 47µF capacitor placed directly at the point where the fan wires connect to the PCB. See application note AN-24 for further details.
MOUNTING THE PAD04 AMPLIFIER
The amplifier is supplied with four 4-40 M/F hex spacers at the four corners of the amplifier. Once the amplifier is seated, secure the module with the provided 4-40 nuts and torque to 4.7 in lb [53 N cm] max. See “Dimensional Information” for a detailed drawing. It is recommended that the heat sink be grounded to the system ground. This can easily be done by providing a grounded circuit board pad around any of the holes for the mounting studs. In addition, it is important that the ground at pin 7 of the PAD04 be connected to the ground plane with a very short wide trace.
MOUNTING THE PAD04-1 AMPLIFIER
In most applications the amplifier must be attached to a heat sink. Spread a thin and even coat of heat sink grease across the back of the PAD04-1 and also the heat sink where the amplifier is to be mounted. Push the amplifier into the heat sink grease on the heat sink while slightly twisting the amplifier back and forth a few times to bed the amplifier into the heat sink grease. On the final twist align the mounting holes of the amplifier with the mounting holes in the heat sink and finish the mounting using 4-40 X 3/16″ hex male-female spacers and torque to 4.7 in oz [3.8 N cm] max. Mount the amplifier to the mother board with 4-40 X 1/4” screws. See Dimensional Information for additional recommendations.
PHASE COMPENSATION
The PAD04 must be phase compensated. The compensation capacitor, CC, is connected between pins 2 and 3. The compensation capacitor must be an NPO type capacitor rated for the full supply voltage (200V). On page 2, under Amplifier Pinout and Connections, you will find a table that gives recommended compensation capacitance value for various circuit gains and the resulting slew rate for each capacitor value. Consult also the small signal response and phase response plots for the selected compensation value in the Typical Performance Graphs section. A compensation capacitor less than 10pF is not recommended.
SINGLE HIGH-CURRENT SUPPLY OPERATION
It is often desirable to operate the PAD04 with a single high-current power supply as this reduces system cost. Figure 2 in the application circuits section shows one way to do this. See also application note AN-46 which details an application for driving ink jet print heads.
TYPICAL PERFORMANCE GRAPHS
SAFE OPERATING AREA
DIMENSIONAL INFORMATION
APPLICATION CIRCUITS
