APEX SA07

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FEATURES
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500kHz SWITCHING
FULL BRIDGE OUTPUT 5-40V (80V P-P)
5A OUTPUT
1 IN2 FOOTPRINT
FAULT PROTECTION
SHUTDOWN CONTROL
SYNCHRONIZABLE CLOCK
HERMETIC PACKAGE
18-PIN DIP
PACKAGE STYLE EL
APPLICATIONS
EXTERNAL CONNECTIONS
• HIGH FIDELITY AUDIO AMPLIFIER
• BRUSH TYPE MOTOR CONTROL
• VIBRATION CANCELLING AMPLIFIER
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DESCRIPTION
The SA07 amplifier is a 40 volt, 500kHz PWM amplifier. The
full bridge output circuit provides 5 amps of continuous drive
current for applications as diverse as high fidelity audio and
brush type motors. Clock output and input pins can be used for
synchronization with other amplifiers or an externally generated
clock. An integrator amplifier is provided. Direct access to the
pwm input is provided for connection to digital motion control
circuits. Protection circuits guard against thermal overloads
as well as shorts to supply or ground. The current limit is programmable with one or two external resistors depending on
the application. A shutdown input disables all output bridge
drivers. The 18 pin steel package is hermetically sealed.
BLOCK DIAGRAM AND
TYPICAL APPLICATION
CONNECTIONS
HIGH FIDELITY
AUDIO
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Case tied to Pin 7. Allow no current in case. Bypassing of supplies is required. If +PWM > RAMP then A OUT > B OUT.
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APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL [email protected]
1
SA07
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
SUPPLY VOLTAGE, +VS to GND, 10mS surge
SUPPLY VOLTAGE, VCC to GND
OUTPUT CURRENT, peak
POWER DISSIPATION, internal
TEMPERATURE, pin solder - 10s
TEMPERATURE, junction2
TEMPERATURE, storage
OPERATING TEMPERATURE RANGE, case
INPUTS
SPECIFICATIONS
PARAMETER
TEST CONDITIONS2
ERROR AMP, CLOCK REF3
OFFSET VOLTAGE
BIAS CURRENT
OFFSET CURRENT
COMMON MODE VOLTAGE RANGE
COMMON MODE REJECTION, DC
SLEW RATE
OPEN LOOP GAIN
GAIN BANDWIDTH PRODUCT
CLOCK OUT
CLOCK OUT, high level
CLOCK OUT, low level
5V OUT
OUTPUT
EFFICIENCY, 5A output
SWITCHING FREQUENCY
CURRENT, continuous
CURRENT, peak3
RDS(ON)3
POWER SUPPLY
VOLTAGE, VCC
VOLTAGE, VS
CURRENT, VCC
CURRENT, VS
LOAD ≤ 5mA
CAUTION
.98
4.7
0
4.988
VS = 40V
100 ms, 10% duty cycle
INPUTS3
ILIM/SHDN, trip point
–PWM, +PWM, low level
–PWM, +PWM, high level
CLOCK IN, low level
CLOCK IN, high level
NOTES: 1.
2.
3.
4.
TYP
0
70
Full temperature range
Full temperature range
Switching
Switching, No Load
THERMAL4
RESISTANCE, junction to case
RESISTANCE, junction to air
TEMPERATURE RANGE, case
MIN
60V
16V
7.5A
80W1
300°C
150°C
–65 to +150°C
–55 to +125°C
–.4/+5.4V
12
100
10
1
5
UNITS
10
50
30
3
1.02
5.3
.2
5.012
mV
pA
pA
V
dB
V/µS
dB
MHz
MHz
V
V
V
55
%
kHz
A
A
Ω
16
40
50
90
V
V
mA
mA
110
.8
Vcc
.3
5.6
mV
V
V
V
V
3.5
°C/W
°C/W
°C
94
500
5
7
10
5
12
90
0
2.7
0
3
Full temperature range
Full temperature range
Meets full range specifications
MAX
15
–25
85
40W in each of the two active output transistors on at any one time.
Unless otherwise noted: TC = 25°C.
Min max values guaranteed but not tested.
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.
The SA07 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: 1 (800) 546-2739
2
SA07
OPERATING
CONSIDERATIONS
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APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL [email protected]
3
SA07
OPERATING
CONSIDERATIONS
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NOISE FILTERING
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GENERAL
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.
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Switching noise can enter the SA07 through the INT OUT
to +PWM connection. A wise precaution is to low pass filter
this connection. Adjust the pass band of the filter to 10 times
the bandwidth required by the application. Keep the resistor
value to 100 ohms or less since this resistor becomes part of
the hysteresis circuit on the pwm comparator.
PCB LAYOUT
�
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 and heat sink selection.
The "Application Notes" and "Technical Seminar" sections
contain a wealth of information on specific types of applications. Information on package outlines, heat sinks, mounting
hardware and other accessories are located in the "Packages
and Accessories" section. Evaluation Kits are available for most
Apex product models, consult the "Evaluation Kit" section for
details. For the most current version of all Apex product data
sheets, visit www.apexmicrotech.com.
CLOCK CIRCUIT AND RAMP GENERATOR
The clock frequency is internally set to a frequency of approximately 1MHZ. 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 RAMP pin.
An external clock signal can be applied to the CLK IN pin for
synchronization purposes. If a clock frequency lower than 1MHz
is chosen an external capacitor must be tied to the RAMP pin.
This capacitor, which parallels an internal capacitor, must be
selected so that the ramp oscillates 2.5 volts p-p with the lower
peak 1.25 volts above ground.
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
The designer needs to appreciate that the SA07 combines
in one circuit both high speed high power switching and low
level analog signals. Certain layout rules of thumb must be
considered when a circuit board layout is designed using the
SA07:
1. Bypassing of the power supplies is critical. Capacitors
must be connected directly to the power supply pins with
very short lead lengths (well under 1 inch). Ceramic chip
capacitors are best.
2. Make all ground connections with a star pattern at pin 7.
3. Beware of capacitive coupling between output connections
and signal inputs through the parasitic capacitance between
layers in multilayer PCB designs.
4. Do not run small signal traces between the pins of the output
section (pins 11-16).
5. Do not allow high currents to flow into the ground plane.
6. Separate switching and analog grounds and connect the
two only at pin 7 as part of the star pattern.
INTEGRATOR
The integrator provides the inverted signal for negative
feedback and also the open loop gain for the overall application circuit accuracy. Recommended value of CINT is 10 pF
for stability. However, poles and zeroes can be added to the
circuit for overall loop stability as required.
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-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 RLIMIT resistors (through the filter
network and shutdown divider resistor) and connect the RLIMIT
resistors directly to the GND pin. Do not connect RLIMIT sense
resistors to the ground plane.
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
4
SA07
OPERATING
CONSIDERATIONS
SHUTDOWN
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The shutdown circuitry makes use of the internal current
limiting circuitry. The two functions may be externally combined
in voltage and current modes as shown below in Figures A
and B. The RLIMIT resistors will normally be very low values and
can be considered zero for this application. In Figure A, RSHDN
and 1K form a voltage divider for the shutdown signal. After a
suitable noise filter is designed for the current limit, adjust the
value of RSHDN to give a minimum 110 mV of shutdown signal
at the I LIMIT/SHDN pin when the shutdown signal is high.
Note that CFILTER will filter both the current limit noise spikes
and the shutdown signal. Shutdown and current limit operate
on each cycle of the internal switching rate. As long as the
shutdown signal is high the output will be disabled.
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PROTECTION CIRCUITS
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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 difficult 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 = .001uF,
RFILTER = 5k .
Circuits monitor the temperature and load on each of the
bridge output transistors. On each cycle should any fault condition be detected all output transistors in the bridge are shut off.
Faults protected against are: shorts across the outputs, shorts
to ground, and over temperature conditions. Should any of
these faults be detected, the output transistors will be latched
off.* In addition there is a built in dead time during which all the
output transistors are off. The dead time removes the possibility
of a momentary conduction path through the upper and lower
transistors of each half bridge during the switching interval.
Noise or flyback may be observed at the outputs during this
time due to the high impedance of the outputs in the off state.
This will vary with the nature of the load.
* To restart the SA07 remove the fault and recycle VCC or,
alternatively, toggle the ILIMIT/SHDN (PIN16) with a shut
down pulse.
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.
This data
sheet has been carefully
checked and is believed
to be reliable,
however,
no responsibility
is assumed
for possible
or omissions.
All specifications
subject to change without notice.
APEX
MICROTECHNOLOGY
CORPORATION
• TELEPHONE
(520)
690-8600
• FAX (520)
888-3329
• inaccuracies
ORDERS (520)
690-8601
• EMAIL are
[email protected]
SA07U REV. B DECEMBER 1998
© 1998 Apex Microtechnology Corp.
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