Datasheet TDA1908 Datasheet (SGS Thomson Microelectronics)

DESCRIPTION

The TDA1908 is a monolithic integrated circuit in
12 lead quad in-line plastic package intended for
lowfrequencypowerapplications.Themountingis
compatiblewith the old types TBA800, TBA810S,
TCA830Sand TCA940N. Its main featuresare:

– flexibility in use with a max output curent of 3A

and an operating supply voltage range of 4V to

30V;
– protectionagainst chip overtemperature;
– soft limiting in saturationconditions;
– low ”switch-on”noise;
– low numberof externalcomponents;
– high supplyvoltagerejection;
– very low noise.

ABSOLUTE MAXIMUM RATINGS

TDA1908

8W AUDIOAMPLIFIER

Findip

ORDERING NUMBER : TDA1908

Symbol Parameter Value Unit

V

s

I

o

I

o

P

tot

T

stg,Tj

Supply voltage 30 V
Output peak current(non repetitive) 3.5 A
Output peak current(repetitive) 3 A

Power dissipation: at T

Storage and junctiontemperature -40 to 150

=80°C

amb

at T

=90°C5W

amb

1W

APPLICATION CIRCUIT

°C

March 1993

1/12

TDA1908

PIN CONNECTION(top view)

SCHEMATIC DIAGRAM

2/12

TDA1908

TEST CIRCUIT

* See fig. 12

THERMALDATA

Symbol Parameter Value Unit

R

th j-tab

R

th j-amb

(°) Obtained withtabs solteredto printed circuit board withmin copper area.

ELECTRICAL CHARACTERISTICS (Refertothetest circuit, T

Thermal resistancejunction-tab max 12
Thermal resistancejunction-ambient max (°)70

=25°C, Rth(heatsink)=8 °C/W, unless

amb

°C/W
°C/W

otherwisespecified)

Symbol Parameter Testconditions Min. Typ. Max. Unit

Supply voltage 4 30 V

V

s

2.5

10.2

16.8

V

Quiescent output voltage Vs=4V

V

o

I

Quiescent drain current Vs=4V

d

Output stage saturation voltage

CEsat

(each output transistor)

Output power

P

o

V

= 18V

s

V

= 30V

s

V

= 18V

s

V

= 30V

s

IC=1A

= 2.5A

I

C

d = 10% f = 1KHz

V

=9V RL=4Ω

s

V

= 14V RL=4Ω

s

V

= 18V RL=4Ω

s

V

= 22V RL=8Ω

s

V

= 24V RL=16Ω

s

1.6

8.2

14.4

7

6.5

4.5

2.1

9.2

15.5
15

17.5
21 35

0.5

1.3

2.5

5.5
9
8

5.3

V

mA

V

W

3/12

TDA1908

ELECTRICAL CHARACTERISTICS (continued)

Symbol Parameter Testconditions Min. Typ. Max. Unit

d Harmonic distorsion

Input sensivity Vs=9V

V

i

V

Input saturation voltage (rms) Vs=9V

i

R

Input resistence (pin 8) f = 1 KHz 60 100

i

I

Drain current f = 1 KHz

s

Efficiency

η

BW Small signal bandwitdth (-3 dB) V

f = 1KHz
V

=9V RL=4Ω

s

P

= 50 mW to 1.5 W

V
V

V
V
V
V

V
V
V

V
V
V
V

V

o

= 18V RL=4Ω

s

= 24V RL=16Ω

s

= 14V

s

= 18V

s

= 22V

s

= 24V

s

= 14V

s

= 18V

s

= 24V

s

= 14V

s

= 18V

s

= 22V

s

= 24V

s

= 18V f = 1 KHz

s

= 18V

s

=50mWto4W

P

o

P

=50mWto3W

o

=4Ω

R

L

R

=4Ω

L

R

=4Ω

L

R

=8Ω

L

R

=16Ω

L

R

=4Ω

L

R

=4Ω

L

R

=8Ω

L

R

=16Ω

L

R

=4Ω Po=9W

L

=4Ω

R

L

0.1

0.1

0.1

P
P
P
P
P

o
o
o
o
o

= 2.5W
= 5.5W
=9W
=8W
= 5.3W

37
52
64
90

110

0.8

1.3

1.8

2.4

P
P
P
P

o
o
o
o

= 5.5W
=9W
=8W
= 5.3W

570
730
500
310

72

P

= 1W 40 to 40 000 Hz

o

%

mV

V

KΩ

mA

%

G

Voltagegain (open loop) f = 1 KHz 75 dB

v

Voltagegain (closed loop)

G

v

Totalinput noise

e

N

S/N Signal to noise ratio

SVR Supply voltage rejection V

T

Termalshut-down junction

sd

temperature

Note :

(°) Weighting filter = curveA.
(° °) Filter with noisebandwidth: 22 Hz to22 KHz.

(*)

= 18V

V

s

f = 1 KHz

(°)

(°°)

= 18V

V

s

P

=9W

o

R

=4Ω

L

= 18V RL=4Ω

s

f

ripple

R

=4Ω

L

=1W

P

o

R

=50Ω

g

R

=1KΩ

g

R

= 10KΩ

g

=50Ω

R

g

R

=1KΩ

g

R

= 10KΩ

g

R

= 10KΩ

g

R

=0

g

R

= 10KΩ

g

R

=0

g

= 100 Hz Rg= 10KΩ

39.5 40 40.5 dB

1.2

1.3

1.5 4.0

2.0

2.0

2.2 6.0

(°)

(°°)

92
94

88
90

40 50 dB

145 ÉC

µV

µV

dB

dB

4/12

TDA1908

Figure 1. Quiescent output
voltage vs.supply voltage

Figur e 4. Dis tortion v s.
output power (R

=16Ω)

L

Figure 2. Quiescent drain
currentvs. supply voltage

Figur e 5. Distor tion vs .
output power (R

=8Ω)

L

Figure 3. Output power vs.
supply voltage

Figur e 6. Distor tion vs .
outputpower (R

=4Ω)

L

Fig ure 7. Dis tort ion v s.
frequency (R

=16Ω)

L

Figur e 8. Distor tion vs .
frequency(R

=8Ω)

L

Figur e 9. Distor tion vs .
frequency(RL=4Ω)

5/12

TDA1908

Figure 10. Open loop
frequency response

Figure 13. Supply voltage
rejectionvs. voltagegain

Figure 11. Output power vs.
input voltage

Figure 14. Supply voltage
rejection vs. source
resistance

Figure 12. Values of capa­citorC

versusgain and B

X

W

Figure 15. Max power
dissipation vs. supply
voltage

Figure 16. Power dissipa­tionand efficiencyvs.output
power (V

6/12

= 14V)

s

Figure 17. Power dissipa­tionand efficiencyvs. output
power(Vs= 18V)

Figure 18. Power dissipa­tionand efficiencyvs. output
power(Vs= 24V)

APPLICATION INFORMATION
Figure19. Applicationcircuit with bootstrap

* R4 is necessary when Vsis less than 10V.

TDA1908

Figure 20. P.C. board and component lay-out of the circuit of fig. 19 (1 : 1 scale)

7/12

TDA1908

APPLICATION INFORMATION (continued)

Figure 21. Application circuit without bootstrap

Figure22.Outputpowervs.
supply voltage (circuit of
fig. 21)

Figure 23. Position control for car headlights

8/12

TDA1908

APPLICATION SUGGESTION

The recommendedvaluesof theexternal componentsarethoseshown on the applicationcircuit offig. 19.
Whenthe supplyvoltageVs is lessthan 10V, a 100Ω resistor mustbe connectedbetween pin1 andpin4
in order to obtain the maximum outputpower.
Different values can be used. The followingtable can help the designer.

Component

R

1

R

2

R

3

R

4

C

1

C

2

C

3

C

4

Raccom.

value

Purpose

10 KΩ Close loop gain

Larger than

raccomanded value

Increase of gain. Decrease of gain.

setting

100 Ω

Close loop gain

Decrease ofgain. Increase ofgain. R

setting.

1 Ω Frequency stability Danger of oscillation at

hight frequencies with
inductiveloads.

100 Ω

Increaseing of output
swing with low Vs.

2.2 µF

Input DC

Lower noise. Higher low

decoupling.

0,1 µF Supply voltage

bypass.

2.2 µF

10 µF

Inverting input DC
decoupling.

Ripple Rejection. Increase of SVR.

Increase of the
switch-on noise

Increase of the
switch-on time.

Smaller than

raccomanded value

Increase quiescent
current.

frequency cutoff.
Higher noise.

Danger of
oscillations.

Higher low
frequency cutoff.

Degradation of
SVR.

Allowed range

Min. Max.

9R

2

/9

1

47Ω 330 Ω

0.1 µF

0.1µF

2.2 µF 100 µF

C

5

47 µF Bootstrap Increase ofthe

10 mF 100 µF
distorsion at low
frequency

C

6

C

7

0.22 µF

1000 µF

Frequency stability. Danger of oscillation.
Output DC

decoupling.

Higher low
frequency cutoff.

9/12

TDA1908

THERMALSHUT-DOWN

The presenceof a thermal limiting circuit offers the
followingadvantages:

1) An overload on the output (even if it is perma­nent),oranabovelimitambienttemperaturecan
be easily supported since the T

cannot be

j

higherthan 150°C.

2) The heatsinkcan have asmaller factor ofsafety
compared with that of a conventional circuit.
Thereis no possibilityof devicedamage dueto
high junction temperature.

Figure 24. Output power
and drain current vs.
case temperature

Figure 25. Output power
and d rain current vs.
case temperature

If, for any reason, the junction temperature in­creaseupto150°C, the thermal shut-downsim­ply reduces the power dissipation and the
currentconsumption.

The maximum allowable power dissipation de­pends uponthesizeof the externalheatsink(i.e. its
thermal resistance); fig. 25 shows the dissipable
power as a function of ambient temperature for
differentthermal resistance.

Fig ure 2 6. Max i mum
power dis sipat ion vs.
ambienttemperature

MOUNTINGINSTRUCTIONS

The thermalpower dissipatedin the circuitmay be
removedby solderingthe tabs to a copper area on
the PC board (see Fig. 27).

During soldering,tab temperaturemustnotexceed
260°C and the soldering time must not be longer
than 12 seconds.

Figure 27. Mounding example Figure 28. Maximum

power dissipation and
thermal resistance vs.
side””

10/12

FINDIP PACKAGE MEHANICAL DATA

DIM.

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

A 3.8 4.05 0.150 0.159

a1 1.5 1.75 0.059 0.069

b 0.55 0.6 0.022 0.024

b1 0.3 0.35 0.012 0.014

c 1.32 0.052

c1 0.94 0.037

D 19.2 19.9 0.756 0.783

E 16.8 17.2 17.6 0.661 0.677 0.693
E1 4.86 5.56 0.191 0.219
E2 10.11 10.81 0.398 0.426

e 2.29 2.54 2.79 0.090 0.100 0.110
e3 17.43 17.78 18.13 0.686 0.700 0.714
e4 7.62 0.300
e5 7.27 7.62 7.97 0.286 0.300 0.314
e6 12.35 12.7 13.05 0.486 0.500 0.514

F 6.3 7.1 0.248 0.280
F1 6.1 6.7 0.240 0.264

G 9.8 0.386

I 7.8 8.6 0.307 0.339
K 6.1 6.5 0.240 0.256
L 2.5 2.9 0.098 0.114

M 2.5 3.1 0.098 0.122

mm inch

TDA1908

K

b

c1

ce5

e6
e3

D

D1

12 7

G

e4

Aa1L

I

M

e

F

F1

61

E1
E2

E

FINDIP

b1

11/12

TDA1908

Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No
licenseis granted byimplication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied.
SGS-THOMSON Microelectronics products are not authorized for use as critical componentsin life supportdevices or systems without express
written approval of SGS-THOMSON Microelectronics.

 1994 SGS-THOMSON Microelectronics - All Rights Reserved

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