ST MICROELECTRONICS TDA7377 Datasheet

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TDA7377

2x30W DUAL/QUAD POWER AMPLIFIER FOR CAR RADIO

HIGHOUTPUTPOWER CAPABILITY:
2x35W max./4Ω
2x30W/4ΩEIAJ
2x30W/4ΩEIAJ
2

x 20W/4Ω @14.4V,1KHz,10%

4

x 6W/4Ω @14.4V,1KHz,10%
x 10W/2Ω @14.4V,1KHz,10%

4
MINIMUM EXTERNAL COMPONENTS

COUNT:
– NO BOOTSTRAPCAPACITORS
– NO BOUCHEROTCELLS
– INTERNALLYFIXEDGAIN (26dB BTL)

ST-BYFUNCTION(CMOSCOMPATIBLE)
NOAUDIBLEPOPDURINGST-BYOPERATIONS
DIAGNOSTICSFACILITYFOR:

– CLIPPING
– OUT TO GND SHORT
– OUT TO V

SHORT

S

– SOFTSHORTAT TURN-ON
– THERMALSHUTDOWN PROXIMITY

Protections:

OUPUTAC/DCSHORTCIRCUIT

BLOCK DIAGRAM

MULTIWATT15V MULTIWATT15H

TDA7377V TDA7377H

ORDERING NUMBERS:

–TOGND
–TOV

S

– ACROSS THE LOAD
SOFTSHORTAT TURN-ON
OVERRATING CHIP TEMPERATURE WITH

SOFTTHERMAL LIMITER
LOADDUMP VOLTAGESURGE
VERYINDUCTIVE LOADS
FORTUITOUSOPEN GND
REVERSEDBATTERY
ESD

September 1998

DIAGNOSTICS

1/10

TDA7377

DESCRIPTION

The TDA7377 is a new technology class AB car
radio amplifier able to work either in DUAL
BRIDGEor QUAD SINGLE ENDEDconfiguration.
The exclusive fully complementarystructureof the
output stage and the internally fixed gain guaran-

tees the highest possible power performances
with extremely reduced component count. The
on-boardclip detectorsimplifiesgain compression
operation. The fault diagnosticsmakes it possible
to detect mistakes during car radio set assembly
and wiring in the car.

GENERALSTRUCTURE

ABSOLUTEMAXIMUM RATINGS

Symbol Parameter Value Unit

Operating Supply Voltage 18 V
DC Supply Voltage 28 V

S

Peak Supply Voltage (for t = 50ms) 50 V
Output Peak Current (not repetitive t = 100µs) 4.5 A
Output Peak Current (repetitive f > 10Hz) 3.5 A
Power Dissipation (T
Storage and Junction Temperature -40 to 150 °C

=85°C) 36 W

case

V

T

stg,Tj

V

V

peak

I
I

P

op

O
O
tot

THERMAL DATA

Symbol Description Value Unit

R

th j-case

Thermal Resistance Junction-case Max 1.8 °C/W

PIN CONNECTION (Topview)

DIAGNOSTICS

2/10

TDA7377

ELECTRICALCHARACTERISTICS

T

=25°C,unless otherwise specified

amb

(Referto the test circuit, V

=14.4V;RL=4Ω; f = 1KHz;

S

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

S

I

d

V

OS

P

O

P

Omax

P

O EIAJ

THD Distortion R

CT Cross Talk f = 1KHz Single Ended

R

IN

G

V

G

V

E

IN

Supply Voltage Range 8 18 V
Total Quiescent Drain Current RL= ∞ 150 mA
Output Offset Voltage 150 mV
Output Power THD = 10%; RL=4

Bridge
Single Ended
Single Ended, R

Ω

18

5.5

=2

Ω

L

20

6

10
Max. Output Power (***) VS = 14.4V, Bridge 31 35 W
EIAJ Output Power (***) VS= 13.7V, Bridge 27 30 W

=4Ω

L

Single Ended, P
Bridge, P

O

= 0.1 to 4W

O

= 0.1 to 10W

0.02

0.03 0.3
70

f = 10KHz Single Ended
f = 1KHz Bridge

f = 10KHz Bridge

Input Impedance Single Ended

Bridge

Voltage Gain Single Ended

Bridge

55

20
10

19
25

60

60
30

15
20

26

21

27
Voltage Gain Match 0.5 dB
Input Noise Voltage Rg= 0; ”A” weighted, S.E.

Non Inverting Channels
Inverting Channels

2
5

Bridge
Rg = 0; 22Hz to 22KHz 3.5 µV

SVR Supply Voltage Rejection R

A

I
V
V
I

SB

SB

SB
SB

pin7

Stand-by Attenuation PO=1W 80 90 dB
ST-BY Current Consumption V
ST-BY In Threshold Voltage 1.5 V
ST-BY Out Threshold Voltage 3.5 V
ST-BY Pin Current Play ModeV

= 0; f = 300Hz 50 dB

g

= 0 to 1.5V 100

ST-BY

=5V 50 µA

pin7

Max Driving Current Under

5mA

Fault (*)

I

cd off

Clipping Detector

d = 1% (**) 90

Output Average Current

I

cd on

Clipping Detector

d = 5% (**) 160 µA

Output Average Current

V

sat pin10

(*) See built-in S/Cprotectiondescription
(**) Pin 10 Pulled-up to5Vwith 10KΩ;R
(***) Saturatedsquare wave output.

Voltage Saturation on pin 10 Sink Currentat Pin 10 = 1mA 0.7 V

=4Ω

L

W
W
W

%
%

dB
dB

dB
dB

K
KΩ

dB
dB

µV
µV

µ

µ

Ω

A

A

3/10

TDA7377

STANDARD TEST ANDAPPLICATION CIRCUIT
Figure 1: Quad Stereo

Note:

C9, C10, C11, C12 could be
reduced if the2Ω operationis not
required.

Figure 2:

Double Bridge

IN FL

ST-BY

10K R1

C1 0.22µF

C2 0.22µF

C4 0.22µF

C3 0.22µF

C8 47µF

10K R1

C7

10µF

ST-BY

IN FR 5

IN RR 11

IN L

C1 0.47µF

C2 0.47µF

C8 47µF

100nF

7

13

4

12IN RL

6

89 10

3

15

14

DIAGNOSTICS

C5

10µF

7

4

13

5

12IN R
11

6

89 10

DIAGNOSTICS

C6

1

2

100nF

3

C10 2200µF

C9 2200µF

C11 2200µF

C12 2200µF

D94AU063A

C4

1

2

15

14

V

S

C5

1000µF

OUT L

OUT R

D94AU064A

OUT FL

OUT FR

OUT RL

OUT RR

V

C3

1000µF

S

Figure 3:

4/10

Stereo/Bridge

IN BRIDGE 12

ST-BY

IN L

IN L

10K

0.22µF

0.22µF

0.47µF

47µF

10µF

13

7

4

3

5

11
6

89 10

DIAGNOSTICS

15

14

V

S

1000µF100nF

1

2200µF

2

2200µF

OUT L

OUT R

OUT

BRIDGE

D94AU065A

TDA7377

High ApplicationFlexibility

The availability of 4 independentchannels makes
it possible to accomplish several kinds of applica­tions ranging from 4 speakers stereo (F/R) to 2
speakersbridge solutions.
In case of working in single ended conditions the
polarity of the speakers driven by the inverting
amplifier must be reversedrespectto those driven
by noninvertingchannels.
This is to avoid phase inconveniences causing
sound alterations especially during the reproduc­tion of low frequencies.

Easy SingleEnded to Bridge Transition

The change from single ended to bridge configu­rations is made simply by meansof a short circuit
across the inputs, that is no need of further exter­nal components.

Gain Internally Fixed to 20dB in Single Ended,
26dB inBridge

Advantagesof this design choice are in termsof:

componentsand space saving
output noise, supply voltage rejection and dis-

tortion optimization.

Silent Turn On/Off and Muting/Stand-by Func­tion

The stand-by can be easily activatedby means of
a CMOS level applied to pin 7 through a RC filter.
Under stand-by condition the device is turned off
completely (supply current = 1µA typ.; output at-
tenuation= 80dB min.).
Every ON/OFFoperationisvirtuallypop free.
Furthemore, at turn-on the device stays in muting
condition for a time determined by the value as­signed to theSVR capacitor.
While in muting the device outputs becomes in­sensitive to any kinds of signal that may be pre­sent at the input terminals. In other words every
transient coming from previous stages produces
no unplesantacousticeffectto the speakers.

The fully complementary output stage was made
possible by the development of a new compo­nent:theST exclusivepower ICV PNP.

A novel design based upon the connectionshown
in fig. 20 has then allowed the full exploitation of
its possibilities.

The clear advantagesthis new approachhas over
classicaloutput stagesare as follows:

Rail-to-Rail Output Voltage Swing With No
Need of Bootstrap Capacitors.

The output swing is limited only by the VCEsat
of the output transistors, which is in the range
of 0.3Ω (R

) each.

sat

Classical solutions adopting composite PNP­NPN for the upper output stage have higher
saturationloss on the top side of the waveform.
This unbalanced saturation causes a signifi­cant power reduction. The only way to recover
power consists of the addition of expensive
bootstrapcapacitors.

Absolute Stability Without Any External
Compensation.

Referring to the circuit of fig. 20 the gain
V

Out/VIn

R2/R1. The DC output (V

is greater than unity, approximately1+

/2) is fixed by an

CC

auxiliaryamplifiercommon to all the channels.
Bycontrollingthe amountof thislocalfeedbackit
is possible to force the loop gain (A*β)toless
thanunityat frequencyfor which the phaseshift
is 180°. This means that the outputbuffer is in­trinsicallystableand notpronetooscillation.
Most remarkably, the above feature has been
achieved in spite of the very low closed loop
gain of the amplifier.
In contrast, with the classical PNP-NPN stage,
the solution adopted for reducing the gain at
high frequencies makes use of external RC
networks,namely the Boucherotcells.

BUILT–INSHORTCIRCUIT PROTECTION

STAND-BYDRIVING(pin7)

Some precautions have to be taken in the defini­tion of stand-by driving networks: pin 7 cannot be
directly driven by a voltagesource whose current
capability is higher than 5mA. In practical cases
a series resistance has always to be inserted,
having it the double purpose of limiting the cur­rent at pin 7 and to smooth down the stand-by
ON/OFF transitions - in combination with a ca­pacitor - for output pop prevention.
In any case, a capacitor of at least 100nF from
pin 7 to S-GND, with no resistance in between, is
necessary to ensure correct turn-on.

OUTPUT STAGE

Figure20:

TheNewOutputStage

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TDA7377

Reliable and safe operation, in presence of all
kinds of short circuit involving the outputs is as­sured by BUILT-IN protectors. Additionally to the
AC/DC short circuit to GND, to V

, across the

S

speaker, a SOFT SHORT condition is signalled
out during the TURN-ONPHASEso assuringcor­rect operation for the device itself and for the
loudspeaker.
This particular kind of protection acts in a way to
avoid that the device is turned on (by ST-BY)
when a resistive path (less than 16 ohms) is pre­sent between the output and GND. As the in­volved circuitry is normally disabled when a cur­rent higher than 5mA is flowing into the ST-BY
pin, it is important, in order not to disable it, to
have the external current source driving the ST­BY pin limitedto 5mA.

This extra function becomes particularly attractive
when, in the single ended configuration, one ca­pacitor is shared between two outputs (see fig.

21).

Figure 21.

Figure22:

ClippingDetectionWaveforms

A current sinking at pin 10 is triggered when a
certain distortion level is reached at any of the
outputs. This function allows gain compression
possibilitywheneverthe amplifieris overdriven.

Supposing that the output capacitor C

out

for any
reason is shorted, the loudspeaker will not be
damaged being this soft short circuit condition re­vealed.

DiagnosticsFacility

The TDA7377 is equipped with a diagnostic cir­cuitry able to detectthe followingevents:

Clippingin the output signal
Thermalshutdown
Outputfault:

– shortto GND
– shortto V

S

– soft short at turnon
The information is available across an open
collector output (pin 10) through a current sink­ing whentheevent is detected

ThermalShutdown

In this case the output 10 will signal the proximity
of the junction temperature to the shutdown
threshold. Typically current sinking at pin 10 will
start ~10°C before the shutdown threshold is
reached.

HANDLING OF THE DIAGNOSTICS INFORMA­Figure23:

OutputFaultWaveforms(seefig. 24)

TDA7377

6/10

TDA7377

Figure 24:

FaultWaveforms

ST-BY PIN

VOLTAGE

2V

OUTPUT

WAVEFORM

Vpin 10

CHECK AT

(TEST PHASE)

CORRECT TURN-ON

TURN-ON

OUT TO Vs SHORT

SOFT SHORT

OUT TO GND SHORT

FAULT DETECTION

D94AU149A

t

t

t

SHORT TO GND

OR TO Vs

TION

As various kinds of information is available at the
same pin (clipping detection, outputfault, thermal
proximity),this signal must be handledproperly in

Figure 25:

Waveforms

ST-BY PIN

VOLTAGE

OUTPUT

WAVEFORM

10

Vpin

WAVEFORM

Vs

orderto discriminateeach event.
This could be done by taking into account the dif­ferent timing of the diagnostic output during each
case.

t

t

D94AU150

CLIPPING

SHORT TO GND

OR TO Vs

t

THERMAL

PROXIMITY

7/10

TDA7377

Normally the clip detector signalling produces a
low level at pin 10 that is shorter than that present
under faulty conditions;based on this assumption

Figure 26.

TDA7377

an interface circuitry to differentiate the informa­tionis representedin the schematicof fig. 26.

PCB-LAYOUTGROUNDING (general rules)

The device has 2 distinct ground leads, P-GND
(POWER GROUND) and S-GND (SIGNAL
GROUND) which are practically disconnected
from each other at chip level. Proper operation re­quires that P-GND and S-GND leads be con­nected together on the PCB-layout by means of
reasonablylow-resistancetracks.

As for the PCB-ground configuration, a star-like
arrangement whose center is represented by the
supply-filtering electrolytic capacitor ground is
highly advisable. In such context, at least 2 sepa­rate paths have to be provided, one for P-GND
and one for S-GND. The correct ground assign-

mentsare as follows:
STANDBY CAPACITOR, pin 7 (or any other

standbydrivingnetworks):on S-GND
SVR CAPACITOR (pin 6): on S-GND and to be

placed asclose as possible to the device.
INPUT SIGNAL GROUND (from active/passive

signal processorstages):on S-GND.
SUPPLY FILTERING CAPACITORS (pins 3,13):

on P-GND. The (-) terminal of the electrolytic ca­pacitorhas to be directly tied to the battery(-) line
and this should represent the starting point for all
the groundpaths.

8/10

TDA7377

DIM.

Dia1 3.65 3.85 0.144 0.152

MIN. TYP. MAX. MIN. TYP. MAX.

A5
B 2.65 0.104
C 1.6 0.063
D 1 0.039
E 0.49 0.55 0.019 0.022

F 0.66 0.75 0.026 0.030

G 1.02 1.27 1.52 0.040 0.050 0.060
G1 17.53 17.78 18.03 0.690 0.700 0.710
H1 19.6 0.772
H2 20.2 0.795

L 21.9 22.2 22.5 0.862 0.874 0.886
L1 21.7 22.1 22.5 0.854 0.870
L2 17.65 18.1 0.695
L3 17.25 17.5 17.75 0.679 0.689 0.699
L4 10.3 10.7 10.9 0.406 0.421 0.429
L7 2.65 2.9 0.104 0.114

M 4.25 4.55 4.85 0.167 0.179 0.191

M1 4.63 5.08 5.53 0.182 0.200 0.218

S 1.9 2.6 0.075 0.102

S1 1.9 2.6 0.075 0.102

mm inch

0.197

0.886

0.713

OUTLINE AND

MECHANICAL DATA

Multiwatt15 V

9 /10

TDA7377

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A5
B 2.65 0.104
C 1.6 0.063
E 0.49 0.55 0.019 0.022
F 0.66 0.75 0.026 0.030

G 1.14 1.27 1.4 0.045 0.050 0.055

G1 17.57 17.78 17.91 0.692 0.700 0.705
H1 19.6
H2 20.2 0.795

L 20.57 0.810
L1 18.03
L2 2.54
L3 17.25 17.5 17.75 0.679 0.689 0.699
L4 10.3 10.7 10.9 0.406 0.421 0.429
L5 5.28 0.208
L6 2.38
L7 2.65 2.9 0.104 0.114

S 1.9 2.6 0.075 0.102

S1 1.9 2.6 0.075 0.102

Dia1 3.65 3.85 0.144 0.152

mm inch

0.197

0.772

0.710

0.100

0.094

OUTLINE AND

MECHANICAL DATA

Multiwatt15 H

10/10