ST TDA7454 User Manual

TDA7454

4 x 35W HIGH EFFICIENCY QUAD BRIDGE

CAR RADIO AMP LIFIER

HIGH OUTPUT POWER CAPABILITY:
4 x 40W/4Ω MAX.
4 x 35W/4Ω EIAJ.
4 x 25W/4Ω @14.4V, 1KHz, 10%
4 x 60W/2Ω MAX.

2Ω DRIVING CAPABILITY
DUAL MODE OPERATING EXTERNALLY

PRESETTABLE: CONVENTIONAL CLASS A­B MODE, HIGH EFFICIENCY MODE

LOW EXTERNAL COMPONENTS CO UNT:
– NO BOOTSTRAP CAPACITORS
– NO EXTERNAL COMPENSATION
– INTERNALLY FIXED GAIN (26dB)

CLIPPING DETECTOR
ST-BY FUNCTION (CMOS COMPA TIBLE)
MUTE FUNCTION (CMOS COMPAT IBLE)
AUTOMU T E AT MINIM UM SUPPLY

VOLTAGE DETECTION
LOW RADIATION

Protections:

OUPUT SHORT CIRCUIT
TO GND ; TO V

; ACROSS THE LOAD

S

3 STEPS OVERRATING CHIP TEMPERA­TURE WITH THERMAL WARNING

LOAD DUMP VOLTAGE
FORTUITOUS OPEN GND

BLOCK & APPLICATION DIAGRAM

MULTIPOWER BCD TECHNOLOGY

Flexiwatt 25

LOUDSPEAKER DC CURRENT
ESD

DESCRIPTION

The TDA7454 is a new BCD technology QUAD
BRIDGE type of car radio amplifier in Flexiwatt25
package spe cially int ended for c ar radio appli catio ns.
Among the features, its superior efficiency per­formance coming from the internal exclusive
structure, makes it the most suitable device to
simplify the thermal management in high power
sets. The dissipated output power under average
listening condition is in fact reduced up to 50%
when compared to the level provided by conven­tional class AB solutions.

March 2001

STD/HI- EFF 16

IN RIGHT

FRONT

ST-BY 4

IN RIGHT

REAR

MUTE 22

IN LEFT

FRONT

IN LEFT

REAR

CD 25

0.22µF

0.22µF

0.22µF

100µF

0.22µF

SVR

V

CC1

6

20

V

CC2

7

11

12

15

10

14

8

9

S-GND

13

5

2

3

19

18

17

TAB

1

21

24

23

D94AU172C

-

RIGHT FRONT

+

+

RIGHT REAR

-

-

LEFT FRONT

+

+

LEFT REAR

-

V

CC

1/13

TDA7454

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

op

V

V

peak

I

O

I

O

P

tot

T

stg

THERMAL DATA

Symbol Description Value Unit

R

th j-case

Operating Supply Voltage 18 V
DC Supply Voltage 28 V

S

Peak Supply Voltage (for t = 50ms) 40 V
Output Peak Current (not repetitive t = 100µs) 8 A
Output Peak Current (repetitive f > 10Hz) 6 A
Power Dissipation T

= 70°C86W

case

, TjStorage and Junction Temperature -55 to 150 °C

Thermal Resistance Junction-case Max 1 °C/W

PIN CONNECTION

(Top view)

25
24
23
22

20
19
18
17
16
15
14

13
12
11
10

9

8
7
6

4
3
2
1

CD
PW GND LR
OUT LR­MUTE
OUT LR+
V

CC2

OUT LF­PW GND LF
OUT LF+
STD/HEFF
IN LF
IN LR
S GND
IN RR
IN RF
SVR
OUT RF+
PW GND RF
OUT RF­V

CC1

OUT RR+
ST-BY
OUT RR­PW GND RR
TAB

D94AU173A

2/13

TDA7454

ELECTRICAL CHARACTERISTICS

T

= 25°C, unless otherwise specified

amb

(Refer to the test circuit V

= 14.4V; RL = 4Ω; f = 1KHz;

S

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

S

I

d

P

o

P

o EIAJ

P

o max.

THD Total harmonic distortion P

C

T

R

IN

G

V

∆G

E

IN

SVR Supply Voltage Rejection f = 300Hz; Vr = 1Vrms;

Supply Voltage Range 8 18 V
Total Quiescent Drain Current 60 140 250 mA
Output Power THD = 10%

THD = 1%
THD = 10% RL = 2Ω;

THD = 1% R

EIAJ Output Power (*) Vs = 13.7V

Vs = 13.7V, RL = 2Ω

Max. Output Power (*) Vs = 14.4V

Vs = 14.4V, RL = 2Ω

= 1W to 10W; STD MODE

O

P

= 1W; HE MODE

O

P

= 10W; HE MODE

O

RL = 2Ω; HE MODE; PO = 3W
R

= 2Ω; HE MODE; PO = 15W

L

= 2Ω;

L

23
18

40
28

32
50

38
55

25
20

42
30

35
52

40
60

0.03

0.04

0.1

0.06

0.15
Cross Talk f = 1KHz to 10KHz 45 55 dB
Input Impedance 11 15 19 KΩ
Voltage Gain 25 26 27 dB
Voltage Gain Match 1 dB

V

Output Noise Voltage Rg = 600Ω 100 150 µV

45 52 dB

= 0 to 100Ω;

R

g

0.3

0.3

0.5

0.3

0.5

BW Power Bandwidth (–3dB) 75 KHz
A

SB

V

sb IN

V

sb OUT

I

sb

A

M

V

M IN

V

M OUT

I

M

CD Clip Det. out Current

(*) Saturated square wave output.

Stand-by Attenuation 90 100 dB
Stand-by in Threshold 1.5 V
Stand-by out Threshold 3.5 V
Stand-by Current Consumption 50 µA
Mute Attenuation 80 90 dB
Mute in Thereshold 1.5 V
Mute out Threshold 3.5 V
Mute pin Current (Sourced) V = 0 to V

V

S max

S

= 18V

Mode Select Switch Standard BTL Mode Op. (V

High Efficiency Mode (V

(Pull up to 5V with 10KΩ)

CD off: P
CD on: THD = 5% 150

Omin

= 10W

pin 16

pin 16

-10 1 10 µA

) Open

)0.5V

5 µA

W
W

W
W

W
W

W
W

%
%
%

%
%

µA

3/13

TDA7454

Figure 1:

Standard Test and Application Circuit.

C8

0.1µF

ST-BY

MUTE

IN RF

IN RR

IN LF

IN LR

(*) OPEN = STANDARD BTL
CLOSED=HI-EFF BTL

R1

10K

R2

10K

C1

0.22µF

C2 0.22µF

C3 0.22µF

C4 0.22µF

C6

0.1µF

C7

1µF

S-GND

4

22

11

12

15

14

13

16 10 25 1

(*)

SW1

C5

100µF

C9

2200µF

Vcc1 Vcc2

620

TDA7454

SVR TAB

CLIP DET

9
8
7

5
2
3

17
18
19

21
24
23

OUT RF

OUT RR

OUT LF

OUT LR

D95AU416

4/13

TDA7454

Figure 2:

P.C.B. and components layout of fig. 1 circuit. (1.25 :1 scale)

COMPONENTS &
TOP COPPER LAYER

BOTTOM COPPER LAYER

5/13

(V)

(V)

(V)

TDA7454

Figure 3:

240

Quiescent Current vs. Supply Voltage

Id (mA)

200

Vi = 0

160

RL = 4 Ohm

120

80

40

8 1012141618

Vs

Figure 5:

60
55
50
45
40
35
30
25
20
15
10

5

8 9 10 11 12 13 14 15 16 17 18

Max. Output Power vs. Supply Voltage

Po ( W)

RL= 4 Ohm

f= 1 KHz

Vs (V)

Figure 4:

45
40
35

Output Power vs. Supply Voltage

Po ( W)

RL= 4 Ohm

f= 1 K Hz

THD= 10 %

30
25
20

THD= 1 %

15
10

5

8 9 10 11 12 13 14 15 16 17 18

Vs

Figure 6:

50
45
40
35
30
25
20
15
10

5

Output Power vs. Supply Voltage

Po (W)

THD = 10 %

RL = 2 Ohm

f = 1 KHz

THD = 1 %

8 9 10 11 12 13 14 15 16

Vs

Figure 7:

75
70
65
60
55
50
45
40
35
30
25
20
15

6/13

Max. Output Power vs. Supply Voltage

Po ( W)

RL= 2 Ohm

f= 1 KHz

8 9 10 11 12 13 14 15 16

Vs (V)

Figure 8:

10

1

THD vs. Output Power

THD (%)

RL = 4 Ohm

HI-EFF MODE

f = 10 KHz

0.1

f = 1 KHz

0

0110

Po (W)

(V)

(Hz)

(Hz)

TDA7454

Figure 9:

10

1

THD vs. Output Power

THD (%)

RL = 2 Ohm

HI-EFF MODE

f = 10 KHz

0.1

f = 1 KHz

0

0110

Figure 11:

10

1

0.1

0

10 100 1000 10000

THD vs. Frequency

THD (%)

RL = 4 Ohm

Po = 1 W
HI-EFF MODE

Po (W)

f

Figure 10:

100

Muting Attenuation vs. Vpin 22

OUT ATTN

90
80
70

Po= 4 W

f= 20 to 20,000 Hz

60
50
40
30
20
10

0

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Vpin22

Figure 12:

Supply Voltage Rejection vs. Fre-

quency

SVR (dB)

100

90

Vripple= 1 Vrms

80

Rg= 0

70
60
50
40
30
20

10 100 1000 10000

f (Hz)

Figure 13:

CROSSTALK (dB)

90

Cross-Talk vs. Frequency

80

Po = 4 W

70

RL = 4 Ohm
Rg = 0

60

HI-EFF MODE

50
40
30
20

10 100 1000 10000

f

Figure 14:

Power Dissipation and Efficiency vs.

Output Power

Ptot (W)

70
65

Vs= 14.4 V

60

RL = 4 x 4 Ohm

55

f = 1 KHz

50
45

HI-EFF MODE

40
35
30
25
20
15
10

5
0

0.1 1 10

n

Ptot

Po (W)

n (%)

70
60
50
40
30
20
10
0

7/13

TDA7454

OPERATING PRINCIPLE.

Thanks to its unique operating principle, the
TDA7454 obtains a substantial reduction of power
dissipation from traditional class-AB amplifiers
without being affected by the massive radiation
effects and complex circuitry normally associated
with class-D solutions.
Its is composed of 8 amplifier blocks, making up
4 bridge-equivalent channels. Half of this struc­ture is drafted in fig 15. These blocks continu­ously change their connections during every sin­gle signal event, according to the instantaneous
power demand. This means that at low volumes
(output power steadily lower than 2.5 W) the
TDA7454 acts as a Single Ended amplifier, condi­tion where block “C” remains disabled and the
block “D” behaves like a buffer, which, by furnish­ing the correct DC biasing (half-Vcc) to each pair
of speakers, eliminate the needs of otherwise re­quired output-decoupling capacitors. At the same
time, SW1 keeps closed. thus ensuring a com­mon biasing point for L-R front / L-R rear speak­ers couples. As a result, t he equivalent circuit be­comes that of fig. 16.

The internal switches (SW1) are high-speed, dis­sipation-free power MOS types, whose realization
has been made possible by the ST- exclusive By­polar-CMOS-DMOS mixed technology process
(BCD). From fig. 16 it can be observed that “A”
and “B” amplifiers work in phase opposition. Sup­posing their output have the same signal (equal
shape/amplitude), the current s ourced by “B” will
be entirely sunk by “A”, while no current will flow
into “D”, causing no power dissipation in the lat­ter.

“A” and “B” are practically configured as a bridge
whose load is constituted by Ra + Rb (= 8 Ohm, if
4 Ohm speakers are used), with considerable ad­vantages in terms of power dissipation. Designat­ing “A” and “B” for the reproduction of either
FRONT or REAR sections of the same channel
(LEFT or RIGHT), keeping the fader in centre po­sition (same amplitude for FRONT and REAR
sections) and using the same speakers, as it hap­pens during most of the time, will transpose this
best-case dissipation condition into practical ap­plications.

To fully take advantage of the TDA7454’s low-dis­sipation feature, it is then especially important to
adopt some criteria in the channels assignment,
using the schematic of fig. 1 as a reference.
When the power demand increases to more than

2.5 W, all the blocks will operate as amplifiers,
SW1 is opened, leading to the seemingly conven­tional bridge configuration of fig. 17.

The efficiency enhancement is based upon the
concept that the average output power during t he
reproduction of normal music/speech programs
will stand anywhere between 10 % and 15 % of
the rated power (@ THD= 10 %) that the amplifier

can deliver. This holds true even at high volumes
and frequent clipping occurrence.

Applied to the TDA7454 (rated power= 25 W),
this will result into an average output level of 2.5

- 3 W in sine-wave operation, region where the
dissipated power is about 50 % less than that of a
traditional amplifier of equivalent power class (see
TDA7454 vs. CLASS-AB characteristics, fig. 18).
Equally favourable is the case shown by fig. 19,
when gaussian-distributed signal amplitudes,
which best simulates the amplifier’s real working
conditions, are used.

APPLICATION HINTS

(ref. to the circuit of fig. 1)
STAND-BY and MUTING (pins 4 & 22)
Both STAND-BY and MUTING pins are CMOS-

compatible. The current sunk by each of them is
about 1 µA. For pop prevention it is essential that
during TURN ON/OFF sequences the muting be
preventively inserted before making stand-by
transitions. But, if for any reason, either muting or
stand-by are not used, they have to be connected
to Vcc through a 100 Kohm (minimum) resis­tance.

The R-C networks values in fig. 1 (R1-C6 and R2­C7) are meant to be the minimum-necessary for
obtaining the lowest pop levels possible. Any re­ductions (especially for R2-C7) will inevitably im­pair this parameter.

SVR (pin 10)
The duty of the SVR capacitor (C5) is double: as-

suring adequate supply-ripple rejection and con­trolling turn ON/OFF operations. Its indicated
value (100 uF) is the minimum-recommended to
correctly serve both the purposes.

INPUTS (pins 11-12-13-14)
The inputs are internally biased at half-Vcc level.

The typical input impedance is 15 KOhm, which
implies using Cin (C1-C2-C3-C4) = 220 nF for ob­taining a theoretical minimum-reproducible fre­quency of 48 Hz (-3 dB). In any case, Cin val­ues can be enlarged if a lower frequency bound
is desired, but, at any Cin enlargement must cor­respond a proportional increase of Csvr (C5), to
safeguard the on/off pop aspect.
The following table indicates the right values to be
used for Cin and Csvr, whose operating voltage
can be 10 V.

LOW FREQUENCY

ROLL-OFF (-3dB)

48 0.22 100
22 0.47 220
16 0.68 330
11 1 470

Cin (µF) Csvr (µF)

8/13

Table 1: MODE SELECTION TA B LE OPERATION OF THE DEVICE

1) STD/HI-EFF (pin 16 = OPEN)

TDA7454

STANDARD QUAD
BRIDGE MODE

HIGH-EFF QUAD
BRIDGE MODE

STANDARD QUAD
SINGLE-ENDED MODE

100 150 170

2) STD/HI-EFF (pin 16 = GND)

HIGH-EFF QUAD BRIDGE MODE

STANDARD QUAD
SINGLE-ENDED MODE

150 170

3) STD/HI-EFF (pin 16 connected as shown in the figure below.

STANDARD QUAD
BRIDGE MODE OR
HIGH-EFF MODE
(Theatsink dependent)

HIGH-EFF QUAD
BRIDGE MODE

STANDARD QUAD
SINGLE-ENDED MODE

100 150 170

Vref

NTC t(Theatsink)STD/HI-EFF (pin 16)

D94AU174A

ST-BY MODE

Tchip (deg)

ST-BY MODE

Tchip (deg)

ST-BY MODE

Tchip (deg)

OUTPUT STAGE STABILITY

The TDA7454’s is intrinsically stable and will
properly drive any kind of conventional car-radio
speakers without the need of supplementary out­put compensation (e.g. Boucherot cells), thus al­lowing a drastic reduction of the external parts
whose number, abated to the essentials, reflects
that of traditional amplifiers. In this respect, per­fect pin-to-pin compatibility with the entire Sgs­Thomson’s 4-BTL family (TDA738X) exists.

STANDARD / HIGH-EFFICIENCY OPERATION
(pin 16)

The TDA7454’s operating mode can be selected
by changing the connection of pin 16, according
to table 1.

At low battery levels (<10 V), the device will auto­matically turn into STANDARD BRIDGE mode, in­dependently from the status of pin 16.

Condition # 3 in table 1 is particularly useful when
the TDA7454’s operation has to be conditioned
by the temperature in other more heat-sensitive
devices in the same environment. The NTC resis­tor is a temperature sensor, to be situated near
the critical part(s), will appropriately drive pin 16
through a low-power transitor. Initially the

TDA7454 can be set to operate as a STANDARD
BRIDGE, turning into HIGH EFFICIENCY mode
only if overheating is recognised in the critical
spot, thus reducing the overall temperature in the
circuit.

CLIPPING DETECTOR / DIAGNOSTIC (pin 25)

The TDA7454 is equipped with a diagnostic func­tion whose output is available at pin 25. This pin
requires a pull-up resistor (10 KOhm min.) to a
DC source that may range from 5 V to Vcc. The
following events will be recognized and signaled
out:

Clipping

A train of negative-going pulses will appear, each
of them syncronized with every single clipping
event taking place in ant of the outputs.
A possible application consists of filtering / inte­grating the pulses and implement a routine for
automatically reducing / restoring the volume us­ing microprocessor - driven audioprocessors, to
counteract the clipping sound-damaging effects.

Overheating

Chip temperatures above 150 oC will be signaled
out at pin 25 in the form of longer-lasting pulses,
as the stepping back into the operating tempera­ture requires some time.

9/13

TDA7454

This constitues a substantial difference from the
“clipping” situation, making the two information
unmistakable. Associated to a suitable external
circuitry, this “warning” signal could be used to
mute some portions of the I.C. (e.g. the rear
channels) or to attenuate the volume.

Short Cir cui t

Some kinds of short circuit (OUT - GND, OUT­Vcc), either present before the power-on or made
afterwards, will cause pin 25 to remain steadily
low as long as the faulty condition persists.
Short-circuits across the speakers will give inter­mittent (pulsed) signalling, proportional to the
output voltage amplitude.

External La y out Grounding

The 4 bridge stuctures have independent power
ground accesses (pins 2,8,18,24), while the sig­nal ground is common to all of them (pin 13). The

Figure 15:

TDA7454’s Half Structure

TAB (pin 1) is connected to the chip substrate
and has to be grounded to the best-filtered
ground spot (usually nearby the minus terminal of
the Vcc-filtering electrolytic capacitor). This same
point should be used as the centre of a multi-track
star-like configuration, or, alt ernatively, as the ori­gin of only two separate tracks, one for P-GND,
one for S-GND, each of them routed to their spe­cific ground pin(s).
This will provide the right degree of separation
between P-GND and S-GND yet assuring the
(necessary) electrical connection between them.
The correct ground assignment for the each ele­ment of the circuit will then be:

POWER GND:

Battery (-), Supply filters (C8, C9), TAB (pin 1).

SIGNAL GND:

Pre-amplifier (Audiprocessor) ground, SVR ca­pacitor (C5), muting/st-by capacitors (C6, C7).

Figure 16:

Single Ended Operation (Po < 2.5W)

A

INF INR

C

F-channel

Figure 17:

INF INR

He Bridge Operation (Po < 2.5W)

+

-

CONTROL

LOGIC

+

A

V

f

C

-

SW1

-

RRRF

+

-

RRRF

+

V

r

B

D

R-channel

D97AU792

B

D

D97AU794

INF INR

AB

D97AU793

+

V

f

-

i

f

-

RRRF

V

r

R

on2

+

D

if-i

r

10/13

TDA7454

Figure 18:

Pdiss (W)

55

Power Dissipation (Sine-Wave)

50
45
40
35

Vs = 14.4 V

RL = 4 x 4 O hm

CLASS-AB

30
25
20
15
10

5
0

0.1 1 10

TDA7454

Po each channel (W)

Figure 19:

Pdiss (W)

Power Dissipation (Gaussian Signals)

45
40
35
30

Vs = 14.4 V

RL = 4 x 4 Ohm

CLASS-AB

25
20
15
10

TDA7454

5
0

0.1 1 10

Pout each channel (W)

11/13

TDA7454

DIM.

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

mm inch

A 4.45 4.50 4.65 0.175 0.177 0.183
B 1.80 1.90 2.00 0.070 0.074 0.079
C 1.40 0.055
D 0.75 0.90 1.05 0.029 0.035 0.041
E 0.37 0.39 0.42 0.014 0.015 0.016

F (1) 0.57 0.022

G 0.80 1.00 1.20 0.031 0.040 0.047

G1 23.75 24.00 24.25 0.935 0.945 0.955

H (2) 28.90 29.23 29.30 1.138 1.150 1.153

H1 17.00 0.669
H2 12.80 0.503
H3 0.80 0.031

L (2) 22.07 22.47 22.87 0.869 0.884 0.904

L1 18.57 18.97 19.37 0.731 0.747 0.762

L2 (2) 15.50 15.70 15.90 0.610 0.618 0.626

L3 7.70 7.85 7.95 0.303 0.309 0.313
L4 5 0.197
L5 3.5 0.138

M 3.70 4.00 4.30 0.145 0.157 0.169

M1 3.60 4.00 4.40 0.142 0.157 0.173

N 2.20 0.086

O 2 0.079

R 1.70 0.067
R1 0.5 0.02
R2 0.3 0.12
R3 1.25 0.049
R4 0.50 0.019

V 5˚ (Typ.)
V1 3˚ (Typ.)
V2 20˚ (Typ.)
V3 45˚ (Typ.)

(1): dam-bar protusion not i ncluded
(2): molding protusion included

OUTLINE AND

MECHANICAL DATA

Flexiwatt25

L2

H

V3

OL3 L4

V

C

H3

G

H1

G1

R3

H2

F

A

R4

N

V2

R2

R

L

L1

V1

R2

B

V

FLEX25ME

L5

R1

R1 R1

V1

D

E

M1

M

12/13

TDA7454

Information furnishe d is beli eved to be accu rate and reliable. However, STMicroelec tronics assumes no res ponsibility for the consequences
of use of such i nformation nor for any i nfringement of patents or ot her rights of third par ties which may result from its use. No license i s
granted by impli cation or otherwis e under any patent or patent righ ts of STMicroelect ronics. Specifica tion mentioned in this publication are
subject to change without notic e. This public ation supers edes and replaces all information prev iously supplied. STMic roelec tronic s products
are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.

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13/13