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FEATURE
* * * * * * * * * * * * HIGH FREQUENCY SWITCHING -- 200 kHz WIDE SUPPLY RANGE--16-200V 15A CONTINUOUS TO 65C CASE 3 PROTECTION CIRCUITS ANALOG OR DIGITAL INPUTS SYNCHRONIZED OR EXTERNAL OSCILLATOR FLEXIBLE FREQUENCY CONTROL REACTIVE LOADS LOW FREQUENCY SONAR LARGE PIEZO ELEMENTS OFF-LINE DRIVERS C-D WELD CONTROLLER
APPLICATIONS
12-PIN POWER DIP PACKAGE STYLE CR
EXTERNAL CONNECTIONS
DESCRIPTION
The SA12 is a pulse width modulation amplifier that can supply 3000W to the load. An internal 400kHz oscillator requires no external components. The clock input stage divides the oscillator frequency by two, which provides the 200 kHz switching frequency. External oscillators may also be used to lower the switching frequency or to synchronize multiple amplifiers. Current sensing is provided for each half of the H-bridge giving amplitude and direction data. A shutdown input turns off all four drivers of the H-bridge output. A high side current limit and the programmable low side current limit protect the amplifier from shorts to supply or ground in addition to load shorts. The H-bridge output MOSFETs are protected from thermal overloads by directly sensing the temperature of the die. The 12-pin hermetic MO-127 power package occupies only 3 square inches of board space.

BLOCK DIAGRAM AND TYPICAL APPLICATION TORQUE MOTOR DRIVER

APEX MICROTECHNOLOGY CORPORATION * TELEPHONE (520) 690-8600 * FAX (520) 888-3329 * ORDERS (520) 690-8601 * EMAIL prodlit@apexmicrotech.com
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SA12
ABSOLUTE MAXIMUM RATINGS
SUPPLY VOLTAGE, +VS SUPPLY VOLTAGE, VCC POWER DISSIPATION, internal TEMPERATURE, pin solder - 10s TEMPERATURE, junction3 TEMPERATURE, storage OPERATING TEMPERATURE RANGE, case INPUT VOLTAGE, +PWM INPUT VOLTAGE, -PWM INPUT VOLTAGE, ILIM TEST CONDITIONS2 IOUT 1mA IOUT 1mA MIN 4.8 0 392 0 3.7
ABSOLUTE MAXIMUM RATINGS SPECIFICATIONS
SPECIFICATIONS
PARAMETER CLOCK (CLK) CLK OUT, high level4 CLK OUT, low level4 FREQUENCY RAMP, center voltage RAMP, P-P voltage CLK IN, low level4 CLK IN, high level4 OUTPUT TOTAL RON4 EFFICIENCY, 10A output SWITCHING FREQUENCY CURRENT, continuous4 CURRENT, peak4 POWER SUPPLY VOLTAGE, VS VOLTAGE, VCC CURRENT, VCC CURRENT, VCC, shutdown CURRENT, VS ILIM/SHUTDOWN TRIP POINT INPUT CURRENT THERMAL3 RESISTANCE, junction to case RESISTANCE, junction to air TEMPERATURE RANGE, case
200V 16V 250W1 300C 150C -65 to +150C -55 to +125C 0 to +11V 0 to +11V 0 to +10V TYP MAX 5.3 .4 408 .9 5.4 .4 UNITS V V kHz V V V V % kHz A A V V mA mA mA mV nA C/W C/W C
400 5 4
VS = 200V OSC in / 2 65C case
196 15 20 16 14
97 200
204
Full temperature range Full temperature range IOUT = 0 No Load
120 15
200 16 80 50 200 110 100 1
90
Full temperature range, for each die Full temperature range Meets full range specifications
12 -25 +85
NOTES: 1. 2. 3. 4.
Each of the two active output transistors can dissipate 125W. Unless otherwise noted: TC = 25C, VS, VCC at typical specification. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to achieve high MTTF. For guidance, refer to the heatsink data sheet. Guaranteed but not tested.
CAUTION
The SA12 is constructed from MOSFET transistors. ESD handling procedures must be observed. The internal substrate contains beryllia (BeO). Do not break the seal. If accidentally broken, do not crush, machine, or subject to temperatures in excess of 850C to avoid generating toxic fumes.
APEX MICROTECHNOLOGY CORPORATION * 5980 NORTH SHANNON ROAD * TUCSON, ARIZONA 85741 * USA * APPLICATIONS HOTLINE: 1 (800) 546-2739
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TYPICAL PERFORMANCE GRAPHS
SA12

APEX MICROTECHNOLOGY CORPORATION * TELEPHONE (520) 690-8600 * FAX (520) 888-3329 * ORDERS (520) 690-8601 * EMAIL prodlit@apexmicrotech.com
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SA12
GENERAL
Please read Application Note 30 on "PWM Basics". Refer to Application Note 1 "General Operating Considerations" for helpful information regarding power supplies, heat sinking and mounting. Visit www.apexmicrotech.com for design tools that help automate pwm filter design; heat sink selection; Apex's complete Application Notes library; Technical Seminar Workbook; and Evaluation Kits.

OPERATING CONSIDERATIONS
CLOCK CIRCUIT AND RAMP GENERATOR
The clock frequency is internally set to a frequency of approximately 400kHz. The CLK OUT pin will normally be tied to the CLK IN pin. The clock is divided by two and applied to an RC network which produces a ramp signal at the -PWM/RAMP pin. An external clock signal can be applied to the CLK IN pin for synchronization purposes. If a clock frequency lower than 400kHz is chosen an external capacitor must be tied to the -PWM/RAMP pin. This capacitor, which parallels an internal capacitor, must be selected so that the ramp oscillates 4 volts p-p with the lower peak 3 volts above ground.
PWM INPUTS
The full bridge driver may be accessed via the pwm input comparator. When +PWM > -PWM then A OUT > B OUT. A motion control processor which generates the pwm signal can drive these pins with signals referenced to GND.
PROTECTION CIRCUITS
A fixed internal current limit senses the high side current. Should either of the outputs be shorted to ground the high side current limit will latch off the output transistors. The temperature of the output transistors is also monitored. Should a fault condition raise the temperature of the output transistors to 165C the thermal protection circuit will latch off the output transistors. The latched condition can be cleared by either recycling the Vcc power or by toggling the I LIMIT/SHDN input with a 10V pulse. See Figures A and B. The outputs will remain off as long as the shutdown pulse is high (10V). When supply voltage is over 100V, these circuits may not protect the FET switches in the case of short circuits directly at the pins of the amplifier. However, a small inductance between the amplifier and the short circuit will limit current rise time and the protection circuits will be effective. A pair of 12 inch wires is adequate inductance.
Switching noise spikes will invariably be found at the I SENSE pins. The noise spikes could trip the current limit threshold which is only 100 mV. RFILTER and CFILTER should be adjusted so as to reduce the switching noise well below 100 mV to prevent false current limiting. The sum of the DC level plus the noise peak will determine the current limiting value. As in most switching circuits it may be dif ficult to determine the true noise amplitude without careful attention to grounding of the oscilloscope probe. Use the shortest possible ground lead for the probe and connect exactly at the GND terminal of the amplifier. Suggested starting values are CFILTER = .01uF, RFILTER = 5k . The required value of RLIMIT in voltage mode may be calculated by: RLIMIT = .1 V / ILIMIT where RLIMIT is the required resistor value, and ILIMIT is the maximum desired current. In current mode the required value of each RLIMIT is 2 times this value since the sense voltage is divided down by 2 (see Figure B). If RSHDN is used it will further divide down the sense voltage. The shutdown divider network will also have an effect on the filtering circuit.
BYPASSING
Adequate bypassing of the power supplies is required for proper operation. Failure to do so can cause erratic and low efficiency operation as well as excessive ringing at the outputs. The Vs supply should be bypassed with at least a 1F ceramic capacitor in parallel with another low ESR capacitor of at least 10F per amp of output current. Capacitor types rated for switching applications are the only types that should be considered. The bypass capacitors must be physically connected directly to the power supply pins. Even one inch of lead length will cause excessive ringing at the outputs. This is due to the very fast switching times and the inductance of the lead connection. The bypassing requirements of the Vcc supply are less stringent, but still necessary. A .1F to .47F ceramic capacitor connected directly to the Vcc pin will suffice.
CURRENT LIMIT
There are two load current sensing pins, I SENSE A and I SENSE B. The two pins can be shorted in the voltage mode connection but both must be used in the current mode connection (see figures A and B). It is recommended that RLIMIT resistors be non-in- ductive. Load current flows in the I SENSE pins. To avoid errors due to lead lengths connect the I LIMIT/SHDN pin directly to the RLIMIT resistors (through the filter network and shutdown divider resistor) and connect the RLIMIT resistors directly to the GND pin.
MODULATION RANGE
The high side of the all N channel H-bridge is driven by a bootstrap circuit. For the output circuit to switch high, the low side circuit must have previously been switched on in order to charge the bootstrap capacitor. Therefore, if the input signal to the SA12 demands a 100% duty cycle upon start-up the output will not follow and will be in a tri-state (open) condition. The ramp signal must cross the input signal at some point to correctly determine the output state. After the ramp crosses the input signal one time the output state will be correct thereafter. In addition, if during normal operation the input signal drives the SA12 beyond its linear modulation range (approximately 95%) the output will jump to 100% modulation.
(c) 2004 Apex Microtechnology Corp.
This data sheet has been carefully checked and is believed to reliable, SHANNON ROAD * is assumed for possible 85741 * USA * APPLICATIONS HOTLINE: 1 (800) 546-2739 APEX MICROTECHNOLOGY CORPORATION * 5980beNORTH however, no responsibilityTUCSON, ARIZONA inaccuracies or omissions. All specifications are subject to change without notice.
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SA12U REV E SEPTEMBER 2004

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