INTERSIL HCA600ACREF

HCA600ACREF
Data Sheet
P RE L I M I NA R Y
October 1999
600W/1000W Full Bandwidth Class D
Amplifier
File Number
4777
Features
• 600W RMS Power into 8Ω
The HCA600ACREF reference
design delivers 600W RMS
power into a 8Ω load and
1000W into a 4Ω load.
The design is part of the Intersil’s Coolaudio™ program that
supports customers to achieve a minimum time-to-market for
audio end products. As part of this program, this design is
offered after execution of a licensing agreement. At that time,
Intersil provides to the licensee a documentation package
containing: 1) a circuit description, 2) schematics, 3) test
and manufacturing information, 4) A bill of materials with all
vendors and vendor part numbers, 5) Intersil’s engineering
support contacts, 6) one evaluation unit.
For more information, visit our web page at
http://www.intersil.com. For technical assistance, call Central
Applications at 1-800-442-7747, or email us at
[email protected].
Licensing Information
• 1000W RMS Power into 4Ω
• THD <0.02% at 1kHz and 450W into 8Ω
• SNR >110dB Relative to Full Power
• Output Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . <200µV
• Constant Group Delay
• DC to 80kHz Small Signal Bandwidth
• Power Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . .28kHz
• Slew Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18V/µs
• Efficiency >90% at 500W into 8Ω
• Meets FCC and EN55013 Requirements for EMC
• Based On the Intersil HCA8001, Audio Specific IC
• Differential or Single Ended Input
• Over-Current, Over-Voltage and Thermal Protection
• Soft Clipping
• Bridgeable up to 4000W
Applications
Contacts for licensing details, reference design evaluation,
and general questions are as follows:
• Sound Reinforcement
• Professional and Commercial Sound Systems
Continental Far East, Email [email protected]
• Powered Speakers
Intersil Cool Audio, Email [email protected]
• Hi-Fi Stereo
Reference Design Block Diagram
SOURCE
2
HCA600ACREF
PRE-AMPLIFIER
220MM (8.7”)
HCA600ACREF
HCA600ACREF
HCA600ACREF
HCA8001
POWER
SUPPLY
78 MM (3.08”)
HCA600ACREF
POWER DISTRIBUTION
SOURCE
1
HCA600ACREF
HEATSINK / EMI SHIELD
FETS AND DIODES
HCA8001
27.9MM (1.1”)
NOTE: The HCA600ACREF can be used in many different commercial and professional applications
including movie theater surround sound systems as depicted in this reference design block diagram.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 407-727-9207 | Copyright © Intersil Corporation 1999
Coolaudio™ is a trademark of Intersil Corporation.
HCA600ACREF
Absolute Maximum Ratings
Operating Conditions
Bus Voltage, VBUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±130V (Note 1)
+/-12V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +/-15V
12VFLT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -Bus +15V
Audio Inputs . . . . . . . . . . . . . . 12V Differential Peak to Peak Voltage
Bus Voltage, VBUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±110V
+/-12V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +/-12V
12VFLT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -Bus +12V
Ambient Temperature Range . . . . . . . . . . . . . . . . . . . . . 0oC to 50oC
NOTE:
1. WARNING: The voltages inside the shield, at the
edge connector, and on the speaker cables are
potentially deadly. Extreme caution is required.
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
RLOAD = 8Ω, VBUS = ±110V, Supply Source Resistance < 2.5Ω, Storage Capacitor > 12,000µF, 12VFLT = 12V,
+/-12V = +/-12V
Electrical Specifications
TA = 25oC
PARAMETER
SYMBOL
TEST CONDITIONS
TYP
UNITS
±110
V
SUPPLY SPECIFICATION
Minimum Bus Voltage
VBUS MIN
±VBUS RMS Current
IV BUS
1kHz Sine Wave, Full Output Power (8Ω load)
3
A
±VBUS RMS Current
IV BUS
1kHz Sine Wave, Full Output Power (4Ω load)
6
A
±VBUS,Q Average Current
IVBUSQ
Quiescent Current, No Signal
60
mA
Current supplied to power output gate driver circuitry
400
mA
1kHz Sine Wave, Full Output Power (8Ω load)
11.5
V
No input signal
40
mA
12V Float Current
I 12VFLTBIAS
Minimum +/-12V
VBIASmin
±12V Max RMS Current
I+/-15V
600W into 8Ω
Rising Under Voltage Lock Out Voltage
VUV Rising
Bus voltage that activates the amplifier
±75
V
Falling Under Voltage Lock Out Voltage
VUV Falling
Bus voltage that shuts down the amplifier
±50
V
ENABLE Threshold Voltage
VENABLE1
Amplifier starts at this voltage, input amplifier muted
1
V
ENABLE Threshold Voltage
VENABLE2
Input amplifiers active and entire amplifier active
2
V
I ENABLE
Internal “Pull Up” Current
25
µA
Maximum Output Power (Note 2)
PMAX8Ω
THD = 1%, 1kHz, RLOAD = 8Ω
600
W
Maximum Output Power (Note 2)
10% THD8Ω
THD = 10%, 1kHz, RLOAD = 8Ω
800
W
Maximum Output Power (Note 2)
PMAX4Ω
THD = 1%, 1kHz, RLOAD = 4Ω
1000
W
Maximum Output Power (Note 2)
10% THD4Ω
THD = 10%, 1kHz, RLOAD = 4Ω
1200
W
ENABLE Internal Source Current
OUTPUT POWER AND EFFICIENCY
Efficiency
PMAXEFF
POUT = 200W, 8Ω
88
%
PMAXEFF
POUT = 500W, 8Ω
95
%
PMAXEFF
POUT = 400W, 4Ω
88
%
PMAXEFF
POUT = 1000W, 4Ω
90
%
0.015
%
110
dB
200
µV
SMPTE, 60Hz and 7kHz, 4:1,
RLOAD = 8Ω at 25W Output
0.02
%
DC
300
µV/V
AMPLIFIER PERFORMANCE
Total Harmonic Distortion + Noise
THD+N
POUT = 400W, RLOAD = 8Ω, 1kHz
Signal to Noise Ratio
VSNR
Relative to full scale output, 600W into 8Ω
Output Noise
VN
Intermodulation Distortion
IMD
PSRR (∆VOUT /∆VBUS)
PSRR
2
HCA600ACREF
RLOAD = 8Ω, VBUS = ±110V, Supply Source Resistance < 2.5Ω, Storage Capacitor > 12,000µF, 12VFLT = 12V,
+/-12V = +/-12V (Continued)
Electrical Specifications
TA = 25oC
PARAMETER
SYMBOL
PSRR (∆VOUT /∆VBUS)
PSRRac
TEST CONDITIONS
120Hz
TYP
UNITS
-65
dB
Amplifier Output Offset Voltage
|VOS|
DC voltage across the speaker, load = 8Ω
2
mV
Amplifier Output Impedance
ZOUT
Measured at 1kHz and 10W Output
16
mΩ
DF
Measured at 1kHz and 10W Output
500
Damping Factor
ADDITIONAL CHARACTERISTICS
Cutoff Frequency, Referenced to 1kHz
FUPPER8
-3dB, RLOAD = 8Ω at 10W Output
80
kHz
Cutoff Frequency, Referenced to 1kHz
FUPPER4
-3dB, RLOAD = 4Ω at 10W Output
70
kHz
20kHz Response, Referenced to 1kHz
FR at 20kHz
-0.5
dB
Maximum Frequency for Full Power RLOAD = 8Ω
28
kHz
Maximum rate of change of the output voltage
18
V/µs
12.0
V
Either Inverting or non inverting input. Unused
input returned to analog ground
26
dB
Power Bandwidth
PBW
Slew Rate
SR
Maximum Switching Ripple on Output
Input Gain
FPWM
AV
Output at 20kHz and 10W, RLOAD = 8Ω
Full Output Power, RLOAD = 8Ω
Input Impedance, Inverting Input
R-INPUT
Differential amplifier input, other input grounded
10
kΩ
Input Impedance, Non Inverting Input
R+INPUT
Differential amplifier input, other input grounded
5
kΩ
Output Signal Phasing
Phasing
Positive going signal on non Inverting input
results in negative going amplifier output
180
Degrees
Over Temperature Shut Down
OTSD
Rising temperature to shutdown amplifier.
Set by an external thermistor
110
oC
Over Temperature Hysteresis
OTH
Difference between rising and falling temperature
shut down and start up points
10
oC
Amplifier Output Current Limit
IL
Absolute Value
25
A
Amplifier Output Current Limit Time
(Note 3)
TIL
Time the amplifier must be in current limiting before
shutdown
50
ms
NOTES:
2. At this power level, the soft clipping circuitry is beginning to activate. It functions to “round off” peaks rather than hard limit as in most linear
amplifiers. This helps to give this amplifier a pleasing sound during limiting. Moreover, this feature also makes the amplifier “sound louder”.
3. This time allows the amplifier to reproduce large, sustained peaks without shutting down, yet is adequate to protect the amplifier output from
shorted speaker lines.
3
HCA600ACREF
HCA600ACREF Connector Pin Designations
PIN
DESIGNATION
FUNCTION
WIRE COLOR
SPECIFICATIONS AND COMMENTS
1
Analog Ground
Input Ground
Black
(22 Gauge)
Connect to ground of pre-amp or connect to pin 18.
2
Non-Inv Input
Audio Input
Phono
Audio applied to pin 2 does not invert the phase of the signal.
Input impedance is 5kΩ.
3
Inv Input
Audio Input
Phono
Pin 3 and 4 are differential inputs. Audio applied to pin 3 inverts
the phase of the signal. Input impedance is 10kΩ.
4
Analog Ground
Input Ground
Black
(22 Gauge)
5
Enable
Enable
Green
(22 Gauge)
6
Fan
Controls fan or drives LED Brown
indicating over temperature (22 Gauge)
shutdown
Optional
7
CL_OUT
Drives LED to indicate
onset of current limit
Grey
(22 Gauge)
Optional
8
SFCL_OUT
Drives LED to indicate soft
clipping is activated
Blue
(22 Gauge)
Optional
9
-12V
- Bias Supply
Purple
(22 Gauge)
50mA, -12V ±10%
10
+12V
+ Bias Supply
Orange
(22 Gauge)
50mA, +12V ±10%
11
PGND
Power Ground
Black
(16 Gauge)
Connect to Star Ground
12
+BUS
Positive Supply
Red
(16 Gauge)
For best results use at least 12,000µF, 160V electrolytic
capacitor. Limit Bus under no load conditions to 130V.
13
+BUS
Positive Supply
Red
(16 Gauge)
14
PGND
Power Ground
Black
(16 Gauge)
15
-BUS
Negative Supply
White
(16 Gauge)
16
-BUS
Negative Supply
White
(16 Gauge)
17
+12VFLT
Floating 12V supply
(referenced to -Bus)
Yellow
(20 Gauge)
18
PGND
Power Ground
Black
(16 Gauge)
Add capacitance to delay startup or pull low to disable amp.
For best results use at least 12,000µF, 160V electrolytic
capacitor. Limit Bus under no load conditions to 130V.
500mA, +12V ±10%
This signal is referenced to the negative rail (-Bus).
Molex Part Numbers: Header - 26-60-5180, Connector - 09-50-8183, Pins - 08-52-0113
WARNING: Insulate wires. Accidental shorts between +/- Bus and bias supplies will damage the amplifier.
4
HCA600ACREF
Typical Performance Curves
1.000
1
LOAD = 8Ω
AMPLIFIER OUTPUT (dBr)
0.0
400W
THD + N (%)
0.1
0.01
20W
LOAD = 4Ω
-1.000
-2.000
-3.000
-4.000
-5.000
0.001
-6.000
100
1k
FREQUENCY (Hz)
10k
FIGURE 1. THD +N (%) vs FREQUENCY LOAD = 8Ω
R=
∞
760
R = 20K
65
528
R = 10K
52
338
39
190
26.0
84
13.0
21
0.0
0.0
0.6 0.12 0.18 2.4
3.0
3.6
4.2
4.8
5.2
1k
FREQUENCY (Hz)
10k
DSA 602A DIGITIZING SIGNAL ANALYZER
1012
78
100
FIGURE 2. AMPLIFIER FREQUENCY RESPONSE
10W - LOAD = 8Ω
OUTPUT POWER (WRMS)
OUTPUT VOLTAGE (VRMS)
AMPLIFIER OUTPUT vs INPUT
90 LOAD = 8Ω
10
30k
100V/DIV
0.0005
10
0.0
6.0
INPUT VOLTAGE (VRMS)
FIGURE 3. AMPLIFIER TRANSFER CHARACTERISTIC WITH
VARIOUS SETTINGS OF SOFT CLIPPING
RESISTOR
1ms/DIV
FIGURE 4. OSCILLOSCOPE DISPLAY OF AMPLIFIER
OUTPUT WITH SOFT CLIPPING CIRCUIT
ENABLED
Soft Clipping
100V/DIV
DSA 602A DIGITIZING SIGNAL ANALYZER
Figures 3, 4 and 5 show the effects of the soft clipping
circuitry within the amplifier. Figure 3 shows the transfer
characteristic of the amplifier for various values of the soft
clipping programming resistor. An important aspect of soft
clipping is the apparent increase in sound level. As soft
clipping is reached, the upper and lower envelop of the
sinewave is gradually reduced. This “soft” rounding reduces
the higher harmonics that would result if hard clipping as
shown in Figure 5 was enabled. Soft clipping also results in
an amplifier with a more pleasing sound. Figure 4 shows the
rounding of the output with soft clipping, while Figure 5
shows the ampler output without soft clipping.
1ms/DIV
FIGURE 5. OSCILLOSCOPE DISPLAY OF AMPLIFIER
OUTPUT WITH SOFT CLIPPING CIRCUIT
DISABLED
5
80k
HCA600ACREF
Full Size Outline of HCA600ACREF Board
AGND
PC BOARD CONNECTIONS SHOWN
FROM THE TOP OR COMPONENT SIDE
1
220 MM (8.7”)
18
+INPUT
-INPUT
AGND
ENABLE
FAN
CLOUT
SFCLOUT
-12V
+12V
PGND
+BUS
+BUS
PGND
-BUS
-BUS
12VFLT
PGND
HCA600ACREFC
TOP VIEW
OUT76.2MM (3.08”)
6
OUT+
HCA600ACREF
Schematic Diagram of HCA600ACREF Board Test Setup
OUTPUT END OF HCA600ACREF
TO AUDIO GENERATOR
OUT-
ANALYZER GND
OUT+
TO DISTORTION ANALYZER INPUT
AMPLIFIER LOAD RESISTOR
- +
1 1
2 2
V V
S
A + - A E F C S
G I I G N A L F
N N N N A N O C
D P P D B
U L
U U
L
T O
T T
E
U
T
MAKE SURE SUPPLY
IS STABLE WITH
CAPACITORS
+
12V
P + + P - - 1 P
G B B G B B 2 G
N U U N U U V N
D S S D S S F D
L
T
+
12V
-
-
12,000µF
+
-
+
120V
+
120V
12,000µF +
-
+
12V
TO EARTH GND
CAUTION: Remove all power when inserting or removing the amplifier board. Make sure power supply capacitors are discharged or damage to the
amplifier may result.
Board Test Equipment and Test Procedure
for Intersil HCA600ACREF Amplifier
Equipment required for evaluation of the Intersil
HCA600ACREF Amplifier is as follows:
1. Few bench supplies can deliver the rated voltage and
current for this amplifier. Furthermore, most linear bench
supplies cannot sink current. If at all possible a 1KVA
transformer (92V-0-92V) and rectifier should be used to
supply main power. See Figure 6. Bench supplies can be
used to provide bias as shown on the next page.
2. Three 12V, 500mA Power Supplies (if transformer with the
required secondary windings is not available).
3. Distortion Analyzer such as the Audio Precision System
One or System Two or equivalent.
4. Load resistors, 8Ω, 500W and 4Ω, 1000W and a fan.
5. Associated connectors and cables.
6. HCA600ACREF Amplifier Board.
Test Procedure for Evaluation of HCA600ACREF
1. The power supply sequencing is not critical with one
exception. The -12V must be applied at the same time or
before the +12V. If not, the amp may not start.
Frequency sweeps should be limited between 3Hz and 80kHz
at high powers. Amplitude vs. frequency sweeps at full power
will not damage the amplifier. Nevertheless, high frequency
(>10kHz) high power continuous sine wave testing may result in
7
a thermal shutdown and in extreme cases failure, so this should
be avoided. Music does not contain high frequency high power
signals so this is not a concern in real applications.
WARNING: This amp is DC coupled. Do not apply DC to
the input. In applications, a DC blocking cap is required in
the preamp or between the preamp and the amplifier. For
example, a 2.2µF film capacitor between the preamp and
the -input will roll the frequency response off at 7Hz (10K
input impedance).
2. THD measurements are not valid if the AP filters are not
used. The AP interprets the carrier of a class D amplifier as
noise. Filters must be used to remove the carrier. Always
make sure that either the 22, 30 or 80kHz filters in the AP
are selected. The 80kHz filter does not attenuate the carrier
completely, and if it is selected an external 80kHz RC filter
should also be used. This filter must use a high quality cap
so that it does not contribute to THD. A 10K metal film
resistor with a 180pF polypropylene cap does the job well.
If the carrier is visible with a scope on the reading output of
the AP, then the AP is including the switching frequency in its
THD+ Noise calculations. The number is not valid.
Selecting the 80kHz filter and using a single pole external
80kHz low pass filter allows the 2nd, 3rd and 4th harmonics
of a 20kHz signal to be observed.
The external RC filter should also be used when measuring
IMD and CCIF.
HCA600ACREF
Block Diagram of HCA600ACREF Test Setup
AUDIO PRECISION OR OTHER DISTORTION ANALYZER
AUDIO PRECISION
SET TO
UNBALANCED
GROUNDED
.
8Ω LOAD
RESISTOR
.
.
.
.
.
.
+12V
+12V
200mA
00
AC
R
EF
.
.
HC
A6
+ -
-12V
+12V
200mA
+ -
A
G
N
D
+
I
N
P
U
T
I
N
P
U
T
A
G
N
D
12VFLT
+12V
500mA
+ -
+BUS (125V)
1
2
V
+
1
2
V
-BUS (-125V)
-
PGND
1kVA POWER SUPPLY
(SEE BELOW)
CAUTION: Remove power and discharge capacitors before removing or inserting the amplifier. Failure to do so may
damage the module.
NOTES:
4. Differential input. input signal to - INPUT and + INPUT returned to analog ground.
5. When using + INPUT, return - INPUT to analog ground.
6. Enable may be left open since a 25µA pull up current will enable the IC. The fan, CL and SFCL all may also be left open.
8
HCA600ACREF
Power Supply For the HCA600ACREF
D3
15A
125V NO LOAD
1kVA TRANSFORMER
-125V NO LOAD
92VAC
92VAC
AC INPUT
+
12,000µF
160V
12,000µF
160V
PINS 12, 13
+BUS
D2
PINS 15, 16
-BUS
15A
D1
D4
PINS 11, 14, 18
PGND
STAR GROUND
19V NO LOAD
19V NO LOAD
13.6VAC
13.6VAC
+
1A
13.6VAC
19V NO LOAD
1,000µF
35V
-
12V
REG
470µF
35V
470µF
35V
12VFLT
12V +12V
REG
-12V
REG
-12V
100µF
16V
PIN 9
-12V
100µF
16V
PIN 17
12VFLT
100µF
25V
PIN 10
+12V
PINS 1, 4
AGND
WARNING: High voltage secondary.
NOTES:
7. D1, D2 are 200V, 3A diodes. These will blow both fuses if either MOSFET in the power amplifier fails short.
8. D3, D4 are 200V, 1A diodes that return energy to the supply if a fuse blows.
FIGURE 6.
Power Supply Specifications
+Bus and -Bus
+12V and -12V
The voltage necessary to achieve full power is ±110V. In an
unregulated supply, the no load voltage will be significantly
higher. The MOSFETs used in the amplifier support the
differential voltage between the buses. That is if the +/-Bus
are 125V, then each MOSFET has to support 250V. The
breakdown of the MOSFETS is 275V. Care must be take to
ensure that under no load, high line conditions this
breakdown voltage is not exceeded. Doing so may damage
the amplifier.
Each supply draws approximately 40mA. Regulation is
required. For best results make sure that the rectified
secondary voltage at minimum line voltage is greater than
the dropout voltage of the regulator. Any 100mA, 12V, linear
regulator can be used.
This limitation makes it difficult to achieve full power from an
unregulated power supply. The output impedance of the
transformer has to be very low and the size of the bulk
capacitance must be large. A better solution is to use a
switching power supply. This allows the amplifier to be used
to its full potential. With an unregulated power supply, 500W
is the maximum power. The amplifier will still be able to
provide 600W transient RMS power.
While not shown in the power supply diagram, high
frequency ceramic caps (0.1µF) should be placed in parallel
with the electrolytic capacitors for the +/-12V bias and
12VFLT. This additional filtering will improve the performance
of the amplifier.
9
12VFLT
This voltage is needed to drive the gates of the MOSFETs.
The current required is on the order of 400mA. This voltage
should also be regulated. The current is high enough that a
1A regulator with heatsinking is required. This supply is
referenced to -Bus. Do not reference this supply to
ground as the amp will be damaged.
NOTE: In applications that use multiple modules, power supplies
can be shared as long as the currents of each supply is scaled
accordingly.
The voltages on +/-Bus are dangerous. Be careful. Do not
touch the components inside the shield when power is
applied. Make sure the bulk capacitance in the power supply
is discharged before disconnecting or connecting the edge
connector. Don’t touch uninsulated speaker wires when the
amp is running at high powers. Diodes D1- D4 are for
required for safety. Use them.
HCA600ACREF
Heat Sinking
The HCA600ACREF heat sink must be supplemented to
achieve full power. The amount of additional heatsinking
depends on the airflow.
For bench testing, a small fan set up within inches of the
board blowing across the shield is sufficient for full power
testing. The resistors used to test the board will also likely
require a fan.
In applications, the internal thermal transfer plate should be
bolted to the chassis. This can be accomplished by either
placing the board horizontally so that the shield is in thermal
contact with the bottom or side of the chassis or by using an
L bracket which mounts to both the chassis and the thermal
plate. The shield will not make good thermal contact with the
thermal transfer plate unless a stiff piece of aluminum is
bolted to the transfer plate from the outside of the shield.
The reference design uses 125 mil aluminum bars for this
purpose. The chassis and L bracket can also serve the same
purpose, allowing the aluminum bars to be discarded. The
aluminum shield is necessary for EMC compliance. Do not
remove it.
To ensure a long and reliable life, the heatsinking should be
designed so that the module typically runs at 70oC or less.
Higher operating temperatures will reduce the lifetime of
the module.
It is also important to use high temperature fiber washers
when mounting the FETs to the transfer plate. Teflon™ and
plastic washers will flow at high temperatures causing the
FETs to loose contact with the transfer plate and fail.
At one third power into 4Ω (333W) the efficiency is 85%. The
amplifier shuts down when the heat sink temperature is
100oC. Allowing for a temperature rise of 50 degrees above
ambient, the thermal resistance of the heat sink must be
approximately 1oC per watt. A fan is highly recommended.
With a small fan, the existing heat sink bolted to the chassis
is more than adequate.
125 mil BARS
SHIELD
large inductor should be glued to the shield and the board,
so that it is anchored securely. Thermal grease between the
transfer plate and shield is required. Place small washers
under the heatsink to lift it up off the board. The washer next
to R3 requires thermal grease on both sides so that the
thermistor used to sense the temperature of the thermal
transfer plate will be in thermal contact.
GROUNDING
As in all audio amplifiers, grounding is important. The
module has two ground planes, power and analog. These
are connected on the board by a zero ohm jumper, R31. In
most applications, this jumper should be removed, and
analog ground should make one and only one connection
with power ground, (star ground) - see Figure 6 for power
supply transformer.
AUTOMATIC RESTART INTO SHORT
The amplifier is capable of distinguishing a low impedance
load from a dead short. If the output is shorted with a low
impedance, the amp will deliver 30A for 50ms and then shut
down. If the impedance is very low (a short), the amplifier will
deliver 50A for a short burst and then shut down. In either
case, power must be cycled by the user to restart the
amplifier. The amp will not shut down if the impedance of the
loudspeaker dips, or if the speakers are momentarily
shorted. In this case, the amplifier limits the current supplied
to the loudspeaker. The amplifier is designed for use with 4Ω
and 8Ω speakers. It is stable into 2Ω and 1Ω loads, but the
magnetics and heatsinking are not designed for low
impedance speakers or multiple speakers in parallel.
If auto restart into a dead short is absolutely required, then
populate R59 with a 10Ω 805 resistor, and change C11 to a
0.1µF, 10V, 1206 capacitor. The current limit time out will
now be 5ms, and the amplifier will always try to restart after
a dead short one or more times. For safety and reliability
issues, if the current ramps to more than 50A on any start up
attempt, the amplifier will shut down and power will need to
be cycled. In this mode, unless the short is removed quickly
the fuses in the power supply will blow. After the short is
removed and the fuses replaced the amp will restart. Most
users should not use auto restart, as it is easier for the
customer to cycle power than replace a fuse.
EMC COMPLIANCE AND POWER SUPPLY WIRING
TRANSFER PLATE
PC BOARD
FIGURE 7.
Assembly
Make sure the FETs are secure, and use thermal grease on
both sides of the aluminum oxide spacers. Glue the
inductors down and ensure that the coils of the output choke
do not run against the shield. This, may cause a short. The
10
As with all Harris reference designs the amplifier meets both
FCC and CE requirements when placed in a suitable chassis
with appropriate use of by-pass capacitance. The audio
input requires a 1000pF NPO capacitor to chassis, and the
+speaker cable requires a 0.047µF 200V NPO or X7R
capacitor. The negative audio input and speaker return
should be grounded to the chassis. A power line filter is also
required to meet conducted emission specifications.
Teflon™ is a trademark of E. I. Du Pont De Nemours and Company.
HCA600ACREF
Power supply wiring is important. The wires for the +/-Bus
must be kept close to their return (power ground). Twisting
the cables is recommended. The bias supplies should also
be kept close to their returns (AGND). Twisting is
recommended. The return for the 12VFLT is the -Bus. The
primary wires for the transformer should be twisted as
should the secondary wires to the rectifiers. When twisting is
not possible, use tie wraps. Low frequency EMI issues are
usually due to radiation from the bridge rectifiers as the
board itself is compliant.
Authorized Intersil Licensing Agents
Asia
Continental Far East, Inc.
3-1-5 Azabudai, Minato-ku
Tokyo 106, Japan
Tel: 03-3584-0339
FAX: 03-3588-0930
All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification.
Intersil semiconductor products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see web site www.intersil.com
Sales Office Headquarters
NORTH AMERICA
Intersil Corporation
P. O. Box 883, Mail Stop 53-204
Melbourne, FL 32902
TEL: (407) 724-7000
FAX: (407) 724-7240
11
EUROPE
Intersil SA
Mercure Center
100, Rue de la Fusee
1130 Brussels, Belgium
TEL: (32) 2.724.2111
FAX: (32) 2.724.22.05
ASIA
Intersil (Taiwan) Ltd.
7F-6, No. 101 Fu Hsing North Road
Taipei, Taiwan
Republic of China
TEL: (886) 2 2716 9310
FAX: (886) 2 2715 3029