Apex SA12 Datasheet

MICROTECHNOLOGY

FEATURE

PULSE WIDTH MODULATION AMPLIFIER

SA12

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• HIGH FREQUENCY SWITCHING — 200 kHz

• WIDE SUPPLY RANGE—16-200V

• 15A CONTINUOUS TO 65°C CASE

• 3 PROTECTION CIRCUITS

• ANALOG OR DIGITAL INPUTS

• SYNCHRONIZED OR EXTERNAL OSCILLATOR

• FLEXIBLE FREQUENCY CONTROL

APPLICATIONS

• REACTIVE LOADS

• LOW FREQUENCY SONAR

• LARGE PIEZO ELEMENTS

• OFF-LINE DRIVERS

• C-D WELD CONTROLLER

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

CONTROL

SIGNAL

3/7V

Vcc

+PWM

–PWM/RAMP

CLK OUT

CLK IN

GND

10

3
4

470pF

56K

OSC

2

1

5

÷2

SA12

∆

USA B

949311

eO

TE

EXTERNAL CONNECTIONS

CLK IN

CLK OUT

+PWM

–PWM/RAMP

GND

1
2
3

TOP

TOP

VIEW

VIEW

4
5
6

12
11
10

9
8
7

*

*

ILIM/SHDN

Case tied to pin 5. Allow no current in case. Bypassing of supplies
is required. Package is Apex MO-127 (STD). See Outline
Dimensions/Packages in Apex data book.

If +PWM > RAMP/–PWM then A OUT > B OUT.
*See text.

CURRENT

LIMIT

PWM

OUTPUT

DRIVERS

SHUTDOWN

CONTROL

9

+V

B OUT

8

11

A OUT

I SENSE A

12

6

ILIM/SHDN

7

I SENSE B

S

MOTOR

1K

5K

RSENSE

µF

.01

1K

RSENSE

ISENSE A
A OUT

VCC

+VS

B OUT
I SENSE B

5V

5V

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SA12

ABSOLUTE MAXIMUM RATINGS

SPECIFICATIONS

ABSOLUTE MAXIMUM RATINGS

SUPPLY VOLTAGE, +V
SUPPLY VOLTAGE, V
POWER DISSIPATION, internal 250W
TEMPERATURE, pin solder - 10s 300°C
TEMPERATURE, junction

S

CC

3

200V
16V

150°C

1

TEMPERATURE, storage –65 to +150°C
OPERATING TEMPERATURE RANGE, case –55 to +125°C
INPUT VOLTAGE, +PWM 0 to +11V
INPUT VOLTAGE, –PWM 0 to +11V

SPECIFICATIONS

INPUT VOLTAGE, I

PARAMETER TEST CONDITIONS

LIM

2

MIN TYP MAX UNITS

0 to +10V

CLOCK (CLK)

CLK OUT, high level
CLK OUT, low level
FREQUENCY 392 400 408 kHz

4

4

I

≤ 1mA 4.8 5.3 V

OUT

I

≤ 1mA 0 .4 V

OUT

RAMP, center voltage 5V
RAMP, P-P voltage 4V
CLK IN, low level
CLK IN, high level

4

4

0.9V

3.7 5.4 V

OUTPUT

TOTAL R
EFFICIENCY, 10A output VS = 200V 97 %
SWITCHING FREQUENCY OSC in ÷ 2 196 200 204 kHz
CURRENT, continuous
CURRENT, peak

ON

4

4

4

65°C case 15 A

20 A

.4 Ω

POWER SUPPLY

VOLTAGE, V
VOLTAGE, V
CURRENT, V
CURRENT, V
CURRENT, V

I

/SHUTDOWN

LIM

S
CC

CC

shutdown 50 mA

CC,
S

Full temperature range 16 120 200 V
Full temperature range 14 15 16 V
I

= 0 80 mA

OUT

No Load 200 mA

TRIP POINT 90 110 mV
INPUT CURRENT 100 nA

THERMAL

3

RESISTANCE, junction to case Full temperature range, for each die 1 °C/W
RESISTANCE, junction to air Full temperature range 12 °C/W
TEMPERATURE RANGE, case Meets full range specifications –25 +85 °C

NOTES: 1. Each of the two active output transistors can dissipate 125W.

2. Unless otherwise noted: TC = 25°C, VS, VCC at typical specification.

3. 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.

4. 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 850°C to avoid generating toxic fumes.

APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: [phone]

TYPICAL PERFORMANCE
GRAPHS

SA12

125

100

75

50

25

EACH ACTIVE
OUTPUT RESISTOR

0

INTERNAL POWER DISSIPATION, (W)

25

0

15

50 125

CASE TEMPERATURE, (°C)

REVERSE DIODE NORMALIZED ON RESISTANCE

75 100

12

9

6

3

POWER DERATING

FLYBACK CURRENT, Isd (A)

0

0.8 1.0 1.2 1.4

0.6
SOURCE TO DRAIN DIODE VOLTAGE

100

CLOCK LOADING

99

98

97

96

NORMALIZED FREQUENCY, (%)

95

CLOCK LOAD RESISTANCE, (Ω)

2.5

2

1.5

1

NORMALIZED TOTAL RDS ON,(X)

.5
–50 0 50 100 150

JUNCTION TEMPERATURE, Tj, (C)

F NOMINAL = 400kHz

10K

CLOCK FREQUENCY OVER TEMP

102.0

101.5

101.0

100.5
100

99.5

99.0

98.5

NORMALIZED FREQUENCY, (%)

98.0
–50

1M100K

–25 0 25 50 75 100 125

CASE TEMPERATURE, (°C)

TOTAL VOLTAGE DROP

12

10

–55° C

85° C

100° C

25° C

–25° C

8

6

125° C

4

2

TOTAL VOLTAGE DROP, (V)

0

0 3 6 9 12 15

OUTPUT CURRENT, (A)

60° C

CONTINUOUS OUTPUT

16

14

12

10

CONTINUOUS AMPS

8

25 50 75 100 125

CASE TEMPERATURE, (°C)

Vcc QUIESCENT CURRENT

115
110
105
100

NORMALIZED Vcc QUIESCENT CURRENT, (%)

Vcc = 15V
F = 22.5 kHz

NORMAL
OPERATION

95
90
85

80

–50 –25 0 25 50 75 100 125

CASE TEMPERATURE, (°C)

SHUTDOWN
OPERATION

DUTY CYCLE VS ANALOG INPUT

100

B OUT

80

60

40

DUTY CYCLE, (%)

20

A OUT

0

35476

ANALOG INPUT, (V)

Vs QUIESCENT VS VOLTAGE

140
120

100

80

60

40

20

0 25 50 75 100 125 150 175 200

NORMALIZED Vs QUIESCENT CURRENT, (%)

Vs, (V)

Vcc QUIESCENT CURRENT

100

90

80

70

60

40

SWITCHING FREQUENCY, F (kHz)

NORMALIZED Vcc QUIESCENT CURRENT, (%)

Vs QUIESCENT VS FREQUENCY

100

80

60

40

20

40

80

SWITCHING FREQUENCY, F (kHz)

NORMALIZED Vs QUIESCENT CURRENT, (%)

120

160

20080 120 160

200

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SA12

OPERATING

CONSIDERATIONS

GENERAL

Helpful information about power supplies, heatsinking and
mounting can be found in the “General Operating Consider­ations” section of the Apex data book. For information on the
package outline, heatsinks, and mounting hardware see the
“Package Outlines” and “Accessories” section of the data
book. Also see Application Note 30 on “PWM Basics.”

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
165°C the thermal protection circuit will latch off the output
transistors. The latched condition can be cleared by either
recycling the V

power or by toggling the I LIMIT/SHDN input

cc

with a 10V pulse. See Figures A and B. The outputs will remain
off as long as the shutdown pulse is high (10V).

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 R
resistors be non-inductive. Load current flows in the I SENSE
pins. To avoid errors due to lead lengths connect the I LIMIT/
SHDN pin directly to the R

resistors (through the filter

LIMIT

network and shutdown divider resistor) and connect the R
resistors directly to the GND pin.

Switching noise spikes will invariably be found at the I
SENSE pins. The noise

I SENSE A

spikes could trip the
current limit threshold
which is only 100 mV.

and C

R

FILTER

FILTER

should be adjusted so
as to reduce the
switching noise well
below 100 mV to

I SENSE B

I LIMIT/SHDN

R

FILTER

C

FILTER

R

LIMIT

5K

IN4148

prevent false current
limiting. The sum of the
DC level plus the noise

FIGURE A. CURRENT LIMIT WITH
SHUTDOWN VOLTAGE MODE.

LIMIT

LIMIT

SHUTDOWN

SIGNAL

0/10V

I SENSE A

5K

peak will determine the
current limiting value. As in
most switching circuits it may

be difficult to determine the
true noise amplitude without
careful attention to grounding
of the oscilloscope probe.

Use the shortest possible

ground lead for

SHUTDOWN

SIGNAL

IN4148

the probe and
connect exactly at
the GND terminal

0/10V

of the amplifier.

I SENSE B

R

LIMIT

I LIMIT/SHDN

R

FILTER

C

R

FILTER

LIMIT

5K

Suggested

FIGURE B. CURRENT LIMIT WITH
SHUTDOWN CURRENT MODE.

The required value of R

LIMIT

in voltage mode may be calcu-

starting values are

= .01uF,

C

FILTER

= 5k .

R

FILTER

lated by:

R
where R

= .1 V / I

LIMIT

is the required resistor value, and I

LIMIT

LIMIT

LIMIT

is the
maximum desired current. In current mode the required value
of each R
divided down by 2 (see Figure B). If R

is 2 times this value since the sense voltage is

LIMIT

is used it will further

SHDN

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 1µF ceramic
capacitor in parallel with another low ESR capacitor of at least
10µF 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 .1µF to .47µF ceramic
capacitor connected directly to the Vcc pin will suffice.

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.

This data sheet has been carefully checked and is believed to be reliable, however, no responsibility is assumed for possible inaccuracies or omissions. All specifications are subject to change without notice.

SA12U REV. C DECEMBER 1999 © 1999 Apex Microtechnology Corp.