Datasheet HCA600ACREF Datasheet (Intersil Corporation)

HCA600ACREF

PRELIMINARY

Data Sheet October 1999

600W/1000W Full Bandwidth Class D
Amplifier

The HCA600ACREFreference
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 achieveaminimumtime-to-market for
audio end products. As part of this program, this design is
offeredafter executionof 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.Fortechnical assistance, call Central
Applications at 1-800-442-7747, or email us at
[e-mail].

File Number 4777

Features

• 600W RMS Power into 8Ω

• 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

Licensing Information

Contacts for licensing details, reference design evaluation,
and general questions are as follows:

Continental Far East, Email [e-mail]
Intersil Cool Audio, Email [e-mail]

Reference Design Block Diagram

SOURCE

SOURCE

12

PRE-AMPLIFIER

HCA600ACREF

HCA600ACREF

HCA600ACREF

HCA600ACREF

POWER DISTRIBUTION

HCA600ACREF

POWER
SUPPLY

Applications

• Sound Reinforcement

• Professional and Commercial Sound Systems

• Powered Speakers

• Hi-Fi Stereo

HCA600ACREF

220MM (8.7”)

HCA8001

78 MM (3.08”)

HEATSINK / EMI SHIELD

FETS AND DIODES

NOTE: TheHCA600ACREFcan be used in manydifferent 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

Coolaudio™ is a trademark of Intersil Corporation.

HCA8001

| Copyright © Intersil Corporation 1999

27.9MM (1.1”)

HCA600ACREF

Absolute Maximum Ratings Operating Conditions

Bus Voltage, V

+/-12V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +/-15V

12VFLT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -Bus +15V

Audio Inputs. . . . . . . . . . . . . . 12V Differential Peak to Peak Voltage

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.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±130V (Note 1)

BUS

Bus Voltage, V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±110V

BUS

+/-12V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +/-12V

12VFLT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -Bus +12V

Ambient Temperature Range. . . . . . . . . . . . . . . . . . . . . 0oC to 50oC

Electrical Specifications R

=8Ω,V

LOAD

+/-12V = +/-12V

= ±110V,Supply Source Resistance < 2.5Ω, Storage Capacitor > 12,000µF, 12VFLT= 12V,

BUS

PARAMETER SYMBOL TEST CONDITIONS

SUPPLY SPECIFICATION

Minimum Bus Voltage V
±V

RMS Current I

BUS

±V

RMS Current I

BUS

±V

Average Current I

BUS,Q

12V Float Current I
Minimum +/-12V V

BUS MIN

V BUS
V BUS

VBUSQ

12VFLTBIAS

BIASmin

±12V Max RMS Current I+/-
Rising Under Voltage Lock Out Voltage V
Falling Under Voltage Lock Out Voltage V
ENABLE Threshold Voltage V
ENABLE Threshold Voltage V
ENABLE Internal Source Current I

UV Rising
UV Falling
ENABLE1
ENABLE2

ENABLE

15V

600W into 8Ω±110 V
1kHz Sine Wave, Full Output Power (8Ω load) 3 A
1kHz Sine Wave, Full Output Power (4Ω load) 6 A
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
Bus voltage that activates the amplifier ±75 V
Bus voltage that shuts down the amplifier ±50 V
Amplifier starts at this voltage, input amplifier muted 1 V
Input amplifiers active and entire amplifier active 2 V
Internal “Pull Up” Current 25 µA

OUTPUT POWER AND EFFICIENCY

Maximum Output Power (Note 2) P

MAX8Ω

Maximum Output Power (Note 2) 10% THD8ΩTHD = 10%, 1kHz, R
Maximum Output Power (Note 2) P

MAX4Ω

Maximum Output Power (Note 2) 10% THD4ΩTHD = 10%, 1kHz, R
Efficiency PMAX

PMAX
PMAX
PMAX

THD = 1%, 1kHz, R

THD = 1%, 1kHz, R

EFFPOUT
EFFPOUT
EFFPOUT
EFFPOUT

= 8Ω 600 W

LOAD

LOAD

= 4Ω 1000 W

LOAD

LOAD

= 200W, 8Ω 88 %
= 500W, 8Ω 95 %
= 400W, 4Ω 88 %
= 1000W, 4Ω 90 %

AMPLIFIER PERFORMANCE

Total Harmonic Distortion + Noise

THD+N

Signal to Noise Ratio V
Output Noise V

SNR

N

P

= 400W, R

OUT

= 8Ω, 1kHz 0.015 %

LOAD

Relative to full scale output, 600W into 8Ω 110 dB

Intermodulation Distortion IMD SMPTE, 60Hz and 7kHz, 4:1,

R

= 8Ω at 25W Output

LOAD

PSRR (∆V

OUT

/∆V

) PSRR DC 300 µV/V

BUS

T

= 25oC

A

UNITSTYP

= 8Ω 800 W

= 4Ω 1200 W

200 µV

0.02 %

2

HCA600ACREF

Electrical Specifications R

LOAD

=8Ω,V

= ±110V,Supply Source Resistance < 2.5Ω, Storage Capacitor > 12,000µF, 12VFLT= 12V,

BUS

+/-12V = +/-12V (Continued)

TA = 25oC

PSRR (∆V

PARAMETER SYMBOL TEST CONDITIONS

/∆V

OUT

) PSRRac 120Hz -65 dB

BUS

UNITSTYP

Amplifier Output Offset Voltage |VOS| DC voltage across the speaker, load = 8Ω 2mV
Amplifier Output Impedance Z

OUT

Measured at 1kHz and 10W Output 16 mΩ

Damping Factor DF Measured at 1kHz and 10W Output 500

ADDITIONAL CHARACTERISTICS

Cutoff Frequency, Referenced to 1kHz F
Cutoff Frequency, Referenced to 1kHz F

UPPER8
UPPER4

20kHz Response, Referenced to 1kHz FR at 20kHz Output at 20kHz and 10W, R
Power Bandwidth P

BW

-3dB, R

-3dB, R

= 8Ω at 10W Output 80 kHz

LOAD

= 4Ω at 10W Output 70 kHz

LOAD

= 8Ω -0.5 dB

LOAD

Maximum Frequency for Full Power R

= 8Ω 28 kHz

LOAD

Slew Rate SR Maximum rate of change of the output voltage 18 V/µs
Maximum Switching Ripple on Output F
Input Gain A

PWM

V

Full Output Power, R

= 8Ω 12.0 V

LOAD

Either Inverting or non inverting input. Unused

26 dB

input returned to analog ground
Input Impedance, Inverting Input R
Input Impedance, Non Inverting Input R

-INPUT

+INPUT

Output Signal Phasing Phasing Positive going signal on non Inverting input

Differential amplifier input, other input grounded 10 kΩ

Differential amplifier input, other input grounded 5 kΩ

180 Degrees

results in negative going amplifier output
Over Temperature Shut Down OT

SD

Rising temperature to shutdown amplifier.

110

o

C

Set by an external thermistor
Over Temperature Hysteresis OT

Difference between rising and falling temperature

H

10

o

C

shut down and start up points
Amplifier Output Current Limit I
Amplifier Output Current Limit Time

(Note 3)

L

T

IL

Absolute Value 25 A

Time the amplifier must be in current limiting before

50 ms

shutdown

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)

2 Non-Inv Input Audio Input Phono Audio applied to pin 2 does not invert the phase of the signal.

3 Inv Input Audio Input Phono Pin 3 and 4 are differential inputs. Audio applied to pin 3 inverts

4 Analog Ground Input Ground Black

(22 Gauge)

5 Enable Enable Green

(22 Gauge)

6 Fan Controls fan or drives LED

indicatingovertemperature
shutdown

7 CL_OUT Drives LED to indicate

onset of current limit

8 SFCL_OUT Drives LED to indicate soft

clipping is activated

9 -12V - Bias Supply Purple

10 +12V + Bias Supply Orange

11 PGND Power Ground Black

12 +BUS Positive Supply Red

13 +BUS Positive Supply Red

14 PGND Power Ground Black

15 -BUS Negative Supply White

16 -BUS Negative Supply White

17 +12VFLT Floating 12V supply

(referenced to -Bus)

18 PGND Power Ground Black

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.

Brown
(22 Gauge)

Grey
(22 Gauge)

Blue
(22 Gauge)

(22 Gauge)

(22 Gauge)

(16 Gauge)

(16 Gauge)

(16 Gauge)

(16 Gauge)

(16 Gauge)

(16 Gauge)
Yellow

(20 Gauge)

(16 Gauge)

Connect to ground of pre-amp or connect to pin 18.

Input impedance is 5kΩ.

the phase of the signal. Input impedance is 10kΩ.

Add capacitance to delay startup or pull low to disable amp.

Optional

Optional

Optional

50mA, -12V ±10%

50mA, +12V ±10%

Connect to Star Ground

For best results use at least 12,000µF, 160V electrolytic
capacitor. Limit Bus under no load conditions to 130V.

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).

4

Typical Performance Curves

1

0.1

400W

HCA600ACREF

1.000

-1.000

-2.000

LOAD = 8Ω

0.0
LOAD = 4Ω

0.01

THD + N (%)

20W

0.001

0.0005
10 100 1k 10k 30k

FREQUENCY (Hz)

-3.000

-4.000

AMPLIFIER OUTPUT (dBr)

-5.000

-6.000
10

100 1k

FREQUENCY (Hz)

FIGURE 1. THD +N (%) vs FREQUENCY LOAD = 8Ω FIGURE 2. AMPLIFIER FREQUENCY RESPONSE

10W - LOAD = 8Ω

AMPLIFIER OUTPUT vs INPUT
LOAD = 8Ω

90

)

78

RMS

65

52

39

26.0

OUTPUT VOLTAGE (V

13.0

0.0

0.0 0.6 0.12 0.18 2.4 3.0 3.6 4.2 4.8 5.2 6.0
INPUT VOLTAGE (V

R = 10K

RMS

R = ∞

)

R = 20K

1012

760

528

338

190

84

21

0.0

)

RMS

OUTPUT POWER (W

DSA 602A DIGITIZING SIGNAL ANALYZER

100V/DIV

1ms/DIV

10k

80k

FIGURE 3. AMPLIFIER TRANSFER CHARACTERISTIC WITH

VARIOUS SETTINGS OF SOFT CLIPPING
RESISTOR

Soft Clipping

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.

5

FIGURE 4. OSCILLOSCOPE DISPLAYOF AMPLIFIER

OUTPUT WITH SOFT CLIPPING CIRCUIT
ENABLED

DSA 602A DIGITIZING SIGNAL ANALYZER

100V/DIV

1ms/DIV

FIGURE 5. OSCILLOSCOPE DISPLAYOF AMPLIFIER

OUTPUT WITH SOFT CLIPPING CIRCUIT
DISABLED

HCA600ACREF

Full Size Outline of HCA600ACREF Board

HCA600ACREFC

PGND

12VFLT

-BUS

-BUS

PGND

+BUS

+BUS

TOP VIEW

PGND

+12V

-12V

SFCLOUT

CLOUT

FAN

ENABLE

AGND

-INPUT

+INPUT

PC BOARD CONNECTIONS SHOWN
FROM THE TOP OR COMPONENT SIDE

AGND

118

OUT-

76.2MM (3.08”)

220 MM (8.7”)

OUT+

6

HCA600ACREF

Schematic Diagram of HCA600ACREF Board Test Setup

TO AUDIO GENERATOR

MAKE SURE SUPPLY

IS STABLE WITH

CAPACITORS

ANALYZER GND

TO DISTORTION ANALYZER INPUT

AMPLIFIER LOAD RESISTOR

-

+

1

1

2

2

V

V

S

F

A
G
N
D

A

+

-

E

C

I

G

I
N
P
U
T

N

N

N

A

P

D

B

U

L

T

E

S

A

L

F

N

O

C

U

L

T

O

U
T

P

+

G

B

N

U

D

S

OUTPUT END OF HCA600ACREF

+
B
U
S

+

12V

+

12V

P

G

B

N

U

D

S

-

-

P

-

-

1

G

B

2

N

U

V

D

S

F
L
T

12,000µF

OUT-

OUT+

+

12V

-

-

+

120V

+

+

12,000µF

120V

-

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.

BoardTestEquipment 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. Three12V,500mAPowerSupplies(iftransformerwiththe
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 s weeps should be limited betw een 3Hz and 80kHz
at high powers. Amplitude vs. frequency s w eeps at full pow er
will not damage the amplifier. Ne v ertheless, high frequency
(>10kHz)high powercontinuous sine wave testing may result in

a thermal shutdown and in extremecases 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 attenuatethe 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 switchingfrequency 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.

7

HCA600ACREF

Block Diagram of HCA600ACREF Test Setup

AUDIO PRECISION OR OTHER DISTORTION ANALYZER

AUDIO PRECISION

SET TO
UNBALANCED
GROUNDED

.

.

.

.

. . . . .

8Ω LOAD
RESISTOR

+12V

HCA600ACREF

-12V

+

-

I

I

A

A

N

N

G

G

P

P

N

U

N

U

D

D

T

T

+

­1

1

2

2

V

V

12VFLT

+BUS (125V)

-BUS (-125V)

PGND

+12V

+12V

+12V

-

1kVA POWER SUPPLY

(SEE BELOW)

200mA

+

200mA

+

500mA

+

-

-

-

-

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

Power Supply For the HCA600ACREF

HCA600ACREF

D3

12,000µF
160V

D4

470µF
35V

15A

15A

-12V
REG

12V

REG

+12V

-12V

PIN 17
12VFLT

AC INPUT

1kVA TRANSFORMER

92VAC
92VAC

13.6VAC

13.6VAC

13.6VAC

+

+

1A

19V NO LOAD

1,000µF
35V

125V NO LOAD

-

19V NO LOAD

-

12VFLT

12V

REG

100µF

25V

-125V NO LOAD

12,000µF
160V

STAR GROUND

19V NO LOAD

470µF
35V

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.

100µF

16V

D1

D2

100µF
16V

PINS 12, 13
+BUS

PINS 15, 16

-BUS

PINS 11, 14, 18
PGND

PIN 10
+12V

PIN 9

-12V

PINS 1, 4
AGND

Power Supply Specifications

+Bus and -Bus

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.

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 improvethe performance
of the amplifier.

+12V and -12V

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.

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.

9

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 70
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

o

100

C. Allowing for a temperature rise of 50 degrees above
ambient, the thermal resistance of the heat sink must be
approximately 1

o

C 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

o

C or less.

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.

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

EMC COMPLIANCE AND POWER SUPPLY WIRING

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: [phone]
FAX: [phone]

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: [phone]
FAX: [phone]

11

EUROPE

Intersil SA
Mercure Center
100, Rue de la Fusee
1130 Brussels, Belgium
TEL: [phone]
FAX: [phone]

ASIA

Intersil (Taiwan) Ltd.
7F-6, No. 101 Fu Hsing North Road
Taipei, Taiwan
Republic of China
TEL: [phone]
FAX: [phone]